Skoda Workshop Service and Repair Manuals

Display groups 000 to 026 Display group 000 in idle (engine warm, coolant temperature not below +80°C)

Display field	Displayed specified value	Corresponds to measured value	Denomination
1	170 to 204	80 to 105°C	Coolant temperature (Precondition for basic setting)
2	20 to 50	1.0 to 2.5 ms	Engine load (without consumers)
3	76 to 841) 76 to 882)	760 to 840 rpm1) 760 to 880 rpm2)	Engine speed (without consumers)
4	146 to 212	10 to 14.5 V	Battery voltage
5	0 to 12	0 to 5°	Throttle valve angle
6	118 to 138	-2.5 through +2.5 kg/h	Control value of idling air mass (idling regulator)
7	112 to 144	-4 through +4 kg/h	Initialisation value idling air mass
8	78 to 178	-10 to +10%	Control value of the fuel preparation (lambda control value) additive (if outside tolerance, perform test drive)
9	243 to 255 or 0 to +131) 0 to +122)	-0.64 to +0.64 ms	Initialisation value of the fuel preparation (lambda initialisation value) (if outside tolerance, perform test drive)
10	118 to 138	-8 to +8%	Initialisation value of the fuel preparation (lambda initialisation value) multiplicative (if outside tolerance, perform test drive)

1) ? 07.97 2) 08.97 ?   Note t  Re display fields 9 and 10: t  In the case of an additive initialisation value the injection period is changed by a fixed rate, which is independent of the basic injection period. t  The multiplicative learned value is a percentage change in the injection period, which is dependent on the basic injection period. Test table - Display group 000

Display field	Display -V.A.G 1552 -	Fault cause	Rectifying fault
1	greater than 204	t  Coolant temperature sender -G62-	–  Test coolant temperature sender -G62- → Chapter
		t  Cable connection to engine control unit
	less than 170	t  Coolant temperature sender -G62-	–  Test coolant temperature sender -G62- → Chapter
		t  Cable connection to engine control unit
		t  Coolant regulator (thermostat) remains open	–  Testing coolant thermostat
2	greater than 50	t  Air conditioning switched on	–  Air conditioning switched off.
		t  Electrical consumers on	–  Switch off el. consumers.
		t  Lambda control on rich or lean load	–  Checking lambda control → Chapter
		t  AC compressor continues operating even though the air conditioning system is switched off	–  Inspecting AC compressor disconnection → Chapter
	less than 20	t  Unmetered air downstream of air-mass meter	–  Eliminate unmetered air.
		t  Unmetered air to throttle valve
		t  Vacuum hose released
		t  Fuel pressure regulator
3	less than 76	t  Driving position engaged (automatic gearbox)	–  Put selector lever in P or N.
		t  Engine loaded by auxiliary equipment	–  Eliminate load (AC, power steering etc.).
		t  Throttle valve control unit -J338- blocks or is defective	–  Inspecting throttle valve control unit -J338- → Chapter
	greater than 841) greater than 882)	t  Idling switch -F60- not closed or defective	–  Interrogate fault memory, checking/adjusting the idling switch -F60-.
		t  large unmetered air volume (cannot be compensated by idle stabilizer)	–  Eliminate unmetered air.
		t  Throttle valve control unit -J338- blocks or is defective	–  Inspecting throttle valve control unit -J338- → Chapter.

1) ? 07.97 2)08.97 ?

Display field	Display -V.A.G 1552 -	Fault cause	Rectifying fault
4	less than 146	t  Generator defective, battery heavily discharged	–  Test voltage, recharge battery
		t  Vehicle voltage heavily loaded just after start by a high charge current or by auxiliary equipment	–  Increase engine speed slightly for a few minutes and switch off additional consumers
		t  Transition resistance in the positive power supply or earth connection for engine control unit	–  Check the supply voltage of the engine control unit → Chapter
		t  Current consumption with ignition off	. –  Eliminate current consumption
	greater than 212	t  Voltage regulator on AC generator defective	–  Test voltage, replace regulator if necessary
		t  Overvoltage due to starting aid or quick charger	–  Interrogating fault memory → Chapter
5	less than 0	t  not possible
	greater than 12	t  Basic setting of the throttle valve control unit not carried out	–  Perform basic setting of the throttle valve control unit → Chapter. –  Interrogating fault memory → Chapter
		t  Throttle cable setting not o.k. t  Throttle valve potentiometer in throttle valve control unit faulty	–  Adjusting throttle control cable → 1.8 l/92 kW Engine, Mechanical Components; Rep. Gr.20
		t  Throttle valve mechanism jams	–  Eliminate cause, if necessary replace
6	less than 118	t  Unmetered air to throttle valve	–  Eliminate unmetered air
	greater than 138	t  increased engine load due to auxiliary equipment	–  eliminate load, switch off additional consumers
7	less than 112	t  Unmetered air to throttle valve	–  Eliminate unmetered air
	greater than 144	t  increased engine load due to auxiliary equipment	–  eliminate load, switch off additional consumers
8	less than 78	t  Mixture too rich, lambda control leans off	–  Press accelerator at 20 second intervals, until learning process is performed.
		t  a lot of fuel from the activated charcoal filter (not in basic setting)
		t  Vacuum hose for fuel pressure regulator leaks	–  Replace vacuum hose.
		t  Lambda learned values on limit	–  Test lambda learned values; display group 008 → Chapter
	greater than 178	t  Mixture too lean, lambda control enriches	–  Testing injection rate → Chapter
		t  Unmetered air	–  Eliminate unmetered air.
		t  Injection nozzles defective
		t  Lambda learned values on limit	–  Test lambda learned values; display group 008 → Chapter
	Display switches or remains contact at 128	t  Fuel level too low t  Lambda control is in operation	–  At least 10 litres of fuel in the tank.
9	less than 243 or greater than 131) greater than 122)		–  Display group 008; display field 2 and 3 → Chapter
10	less than 118 or greater than 138		–  Display group 008; display field 2 and 3 → Chapter

1) ? 07.97 2)08.97 ? Display group 001 - Basic functions

Read measured value block 1 →				← Readout on display
xxx rpm	1.0...2.5 ms	0...5∠°	XX.X° BTDC
1	2	3	4	← Display field
				Ignition angle	? 07.97 : 3 to 12° b. TDC (b. TDC) 08.97 ? : 6 to 12° b. TDC (b. TDC)
			Throttle valve angle Readout when accelerator pedal fully depressed is 80 to 90 ∠° as soon as a fault is detected at the throttle valve potentiometer, a fixed replacement value of 35 ∠° is displayed
		Engine load (injection time per crankshaft rotation)
	Idling speed		? 07.97 : 760 to 840 rpm 08.97 ? : 760 to 880 rpm

Test table - Display group 001

Display field	Display -V.A.G 1552 -	Fault cause	Rectifying fault
1	less than 760 rpm	t  Gear engaged (automatic gearbox)	–  Put selector lever in P or N.
		t  Engine loaded by auxiliary equipment	–  Eliminate load (AC, power steering = wheel in straightahead position etc.).
		t  Throttle valve control unit -J338- blocks or is defective	–  Inspecting throttle valve control unit -J338- → Chapter.
	greater than 840 rpm 1) greater than 880 rpm 2)	t  Idling switch -F60- not closed or defective	–  Interrogate the fault memory → Chapter.
		t  large unmetered air volume (cannot be compensated by idle stabilizer)	–  Eliminate unmetered air.
		t  Throttle valve control unit -J338- blocks or is defective	–  Inspecting throttle valve control unit - J338- → Chapter.
		t  Air conditioning switched off	–  Air conditioning switched off.
2	less than 1.0	t  lower value can only occur during trailing throttle driving
	greater than 2.5	t  poor idling (not running on all cylinders)	–  Injector or spark plugs faulty - replace.
		t  Air mass meter faulty -G70-	–  Interrogate the fault memory → Chapter.
		t  Throttle valve control unit -J338- defective	–  Inspecting throttle valve control unit -J338- → Chapter.
		t  Electrical consumers on	–  Switch off el. consumers.
		t  Steering wheel at limit stop	–  Turn steering wheel into middle position.
		t  Gear engaged (automatic gearbox)	–  Put selector lever in P or N.
3	greater than 5 ∠°	t  Basic setting of the throttle valve control unit not carried out -J338-	–  Perform basic setting of the throttle valve control unit -J338-.
		t  Throttle valve potentiometer in throttle valve control unit -J338- faulty.	–  Inspecting throttle valve control unit - J338- → Chapter.
		t  Throttle cable setting	–  Adjusting throttle control cable → 1.8 l/92 kW Engine, Mechanical Components; Rep. Gr.20
		t  Throttle valve jams	–  Eliminate cause.
4	less than 3° b. TDC 1) less than 6° b. TDC 2)	t  Electrical consumers on	–  Switch off consumers.
		t  Steering wheel at limit stop	–  Turn steering wheel into middle position.
		t  Gear engaged (automatic gearbox)	–  Put selector lever in P or N.
	greater than 12° b. TDC	t  Unmetered air	–  Eliminate unmetered air.

1) ? 07.97 2) 08.97 ?   Note t  Re display field 3: t  When accelerator fully depressed, the read off value is between 75 to 95 ∠°. Display group 002, Basic functions:

Read measured value block 2 →				← Readout on display
xxx rpm	1.0...2.5 ms	2.0...5.0 ms	2.0...4.0 g/s
1	2	3	4	← Display field
				Drawn in air mass
			corrected injection time per working cycle
		Engine load (injection time per crankshaft rotation)
	Idling speed		? 07.97 : 760 to 840 rpm 08.97 ? : 760 to 880 rpm

Test table - Display group 002

Display field	Display -V.A.G 1552 -	Fault cause	Rectifying fault
1		t  see test table - display group 001, display field 1 → Chapter
2		t  see test table - display group 001, display field 2 → Chapter
3	less than 2.0	t  high fuel volume from the activated charcoal filter system (ACF)	–  Testing solenoid valve for activated charcoal filter → Chapter.
		t  incorrect injection valves with too great flow rate fitted	–  Testing injection rate → Chapter.
	greater than 5.0	t  Increased engine load due to electric consumers, air conditioning system, engaged driving position or power steering to the limit	–  Eliminate load by switching off the el. consumers.
4	less than 2.0	t  Large quantity of unmetered air between intake manifold and air mass meter	–  Eliminate unmetered air.
	greater than 4.0	t  Driving position engaged	–  Put selector lever in P or N.
		t  Engine loaded by auxiliary equipment	–  Eliminate load (air conditioning, power steering etc.)

Note t  to display group 002: t  The injection time is displayed in the display field 2, which corresponds to the inducted air mass and the engine load in idle. This relates to a calculated, theoretical value, which is only specific to the crankshaft rotation. The engine load in idle refers to the self-friction of the engine that has to be overcome and the drive of the auxiliary units. The drawn in air mass is displayed in the display field 4. t  In the display field 3 is specified the injection time which is obtained at a full working cycle i.e. two crankshaft rotations. t  In the display field 3 is indicated the corrected, actual injection time and not the dual value of the display field 2. Corrected from influence factors such as: Lambda control; fuel feed of activated charcoal filter system, airtight, air temperature, onboard voltage (fast or slow opening of the injectors) t  If the engine suctions e.g. unmetered air, only the calculated value in the display field 2 must be changed (injection time per crankshaft rotation). The actual injection time per working cycle is maintained by the lambda control to the nominal value. Display group 003, Basic function:

Read measured value block 3 →				← Readout on display
xxx rpm	10.0...14.5 V	80...105 °C	... °C
1	2	3	4	← Display field
				Intake manifold temperature
			Coolant temperature
		Battery voltage
	Idling speed		? 07.97 : 760 to 840 rpm 08.97 ? : 760 to 880 rpm

Note t  Re display field 4: t  A value of the nominal values is not possible, as the display depends mainly on the ambient temperature. Test table - Display group 003

Display field	Display -V.A.G 1552 -	Fault cause	Rectifying fault
1		t  see test table - display group 001, display field 1 → Chapter
2	below 10 V	t  Generator defective, battery heavily discharged	–  Test voltage, recharge battery.
		t  Vehicle voltage heavily loaded just after start by a high charge current or by auxiliary equipment	–  Increase engine speed slightly for a few minutes and switch off additional consumers.
		t  Transition resistance in the power supply or earth connection for engine control unit	–  Test voltage supply of engine control unit → Chapter.
		t  Current consumption with ignition off	–  Rectify any current drain.
	greater than 14.5 V	t  Voltage regulator on AC generator defective	–  Test voltage, replace regulator if necessary.
		t  Overvoltage due to starting aid or quick charger	–  Interrogate the fault memory → Chapter.
3	below 80°C	t  Engine too cold	–  Conduct road test if necessary.
		t  Coolant temperature sender or cable connection to engine control unit	–  Test coolant temperature sender -G62- → Chapter.
	above 105°C	t  Radiator dirty	–  Clean radiator.
		t  Radiator fan not operational	–  Inspecting proper operation.
		t  Coolant regulator (thermostat) defective	–  Testing coolant regulator.
		t  Coolant temperature sender or wiring	–  Test coolant temperature sender -G62- → Chapter.
4	constant 19.5°C	t  Fault at intake air temperature sender -G42- detected	–  Interrogate the fault memory → Chapter.
		t  Intake air temperature sender -G42-	–  Test sender -G42- → Chapter.

Note t  Re display field 3: t  As soon as the fault 16500 (coolant temperature sender -G62-) is stored in the fault memory, the engine control unit uses the intake air temperature as a replacement value to start the engine. The temperature sequence in the range 20°C to 60°C is compared to a model sequence stored in the display field 3. The rise in the model sequence is slower than the real value. If the real values become too slow as a result of a fault they will eventually coincide with the model values. The engine control unit recognises such fault as implausible. Display group 004, basic function:

Read measured value block 4 →				← Readout on display
0....5 ∠°	-1.7..+1.7 g/s	-1.7..+1.7 g/s	Idling
1	2	3	4	← Display field
				Operating state (idling, part load, full load, enrichment, overrun)
			Idling air mass initialised with engaged driving position (for vehicles with an automatic gearbox) on vehicles with manual gearbox 0 is always displayed
		Idling air mass initialised (without driving position for vehicles with an automatic gearbox)
	Throttle valve angle

Test table - Display group 004

Display field	Display -V.A.G 1552 -	Fault cause	Rectifying fault
1		see test table - display group 001, display field 3 → Chapter
2	lower than -1.7 g/s	t  Unmetered air to throttle valve	–  Eliminate unmetered air.
	higher than +1.7 g/s	t  high load due to auxiliary equipment	–  Switch off air conditioning system and electrical components.
		t  Restriction or foreign bodies in the suction range	–  Eliminate restriction or foreign bodies.

Note t  Re display fields 2 and 3: t  The display shows to what extent the idling stabilizer has disinitialised from the constructively given mean value. On a new engine the value is in the positive region because of the higher friction. On a run-in engine it is in the negative region. The values of - 1.7 g/s in combination with a too low value in the display group 005, display field 3 are subject to unmetered air. t  The displayed value is not measured by the air mass meter but calculated from the information of the throttle valve potentiometer. Display group 005, idle stabilizer: (idle)

Read measured value block 5 →				← Readout on display
XXX rpm	800/860 rpm	-10,0...10,0 %	2.0...4.0 g/s
1	2	3	4	← Display field
				Air mass
			Idling regulator
		Engine speed (nominal) is displayed in ten steps manual gearbox: 800 rpm (AC system off) manual gearbox: 860 rpm (AC system on) automatic gearbox: 800 rpm (AC system off) automatic gearbox: 860 rpm (AC system on)
	Idling speed		? 07.97 : 760 to 840 rpm 08.97 ? : 760 to 880 rpm
	Maximum value: 2550 rpm

Note t  Re display field 3: t  The required idling air mass changes at constant speed due to the change of the load ratio in idle. t  The change of the idling air mass is displayed in %. As soon as this change is compensated for through the learning process of the idle stabilizer, the average value is set. The size of the variation of the average value depends on the size of the load change (e.g. by switching on or off the electrical components). t  The learning process is carried out in small steps according to each closing of the idling switch. Several steps are required in case of larger variations. To do so, the accelerator pedal must be briefly tipped in intervals of approx 20 seconds (blip throttle). Thereby, a further step of the learning process is carried out each time. t  The “non initialised” variation then appears in the display group 004, display field 2. The values of the idling regulator are not within the tolerance, if the initialisation values in the display group 004, display field 2 have reached the limit values. t  Limit values: - 1.7 or + 1.7 g/s   Note t  Re display field 4: t  In case of fault (00670) throttle valve positioner: constant speed 840 rpm and air flow rate 2.8 g/s. t  In case of fault (00670 / 16505 / 16506 / 16507) throttle valve positioner and throttle valve potentiometer, the digital idle stabilizer (DLS) is switched off and a constant speed of approx 1000 rpm and an air mass of 2.8 g/s is applied. Display group 006, idle stabilizer:

Read measured value block 6 →				← Readout on display
XXX rpm	-10,0...10,0 %	-10,0...10,0 %	XX.X° BTDC
1	2	3	4	← Display field
				Ignition angle	? 07.97 : 3 to 12° b. TDC (b. TDC) 08.97 ? : 6 to 12° b. TDC (b. TDC)
			Lambda regulator
		Idling regulator
	Idling speed		? 07.97 : 760 to 840 rpm 08.97 ? : 760 to 880 rpm

Test table - Display group 006

Display field	Display -V.A.G 1552 -	Fault cause	Rectifying fault
1		see test table - display group 001, display field 1 → Chapter
2		see test table - display group 005, display field 3 → Anchor
3	not within tolerance	t  Negative display, Engine too rich, Effect: lambda control leans off t  Positive display (+ is not displayed), engine too lean, Effect: Lambda control produces a richer mixture
		t  Unmetered air	–  Eliminate unmetered air.
		t  Injection valve defective	–  Testing injection rate → Chapter.
		t  Lambda learned value on limit	–  Test lambda learned value; display group 008 → Chapter
4		see test table - display group 001, display field 4 → Chapter

Note t  Re display field 3: t  Readout must fluctuate around zero. If 0 is constantly displayed, the lambda control has switched from closed-loop to open-loop control because of a fault in the lambda control. Interrogate the fault memory → Chapter. t  Operating state of lambda control: Display group 021, test display field 4. Display group 007, lambda control and activated charcoal filter system:

Read measured value block 7 →				← Readout on display
-10,0...10,0 %	0.0...1.0 V	0...99%	0,3 ...1,25
1	2	3	4	← Display field
				Lambda correction factor for active fuel tank ventilation
			On/Off ratio of solenoid valve 1 for activated charcoal filter -N80- On/Off ratio 0% means -N80- closed On/Off ratio 99% means -N80- fully open
		Lambda probe voltage
	Lambda regulator

Test table - Display group 007

Display field	Display -V.A.G 1552 -	Fault cause	Rectifying fault
2	If the display does not fluctuate (constant 0.00 to 0.30 V or constant 0.70 to 1.00 V)	t  large unmetered air volume	–  Inspect intake system for leaks → Chapter.
		t  Spark plug defective	–  Inspect spark plugs
		t  Fuel pressure too low or too high	–  Testing fuel pressure regulator and holding pressure → Chapter.
		t  Injection valve defective	–  Testing injection valves → Chapter.
		t  Coolant temperature sender -G62- faulty	–  Test coolant temperature sender → Chapter.
		t  Solenoid valve 1 for activated charcoal filter	–  Inspect tank ventilation → Chapter.
		t  Lambda probe heater does not operate	–  Check lambda probe heater → Chapter.
		t  Lambda probe defective or dirty	–  Checking lambda probe → Chapter.
	constant 1.00 V	t  Short-circuit to positive terminal in: Lambda probe, lambda probe cable, earth lead, engine control unit	–  Check lambda probe heater → Chapter.
	constant between 0.40 to 0.50 V	t  Short-circuit to positive terminal in: Lambda probe, lambda probe cable, earth lead, engine control unit	–  Test lambda probe signal line and control → Chapter.
	constant 0.00 V	t  Short-circuit to positive terminal in: Lambda probe, lambda probe cable, earth lead, engine control unit

Note t  Re display field 2: t  The voltage signal “mixture rich (little residual oxygen)” is at approx. 0.7..1.0 V (related to reference mass). t  The voltage signal “mixture lean (little residual oxygen)” is at approx. 0.0...0.3 V (related to reference mass). t  During the transition from “rich” to “lean” and vice versa (lambda = 1.0) there is a voltage jump from 0.7 to 1.0 V to 0.0 to 0.3 V or vice versa. t  In view of the steep voltage jump the lambda control is not able to maintain constant the ideal mixture composition which corresponds to the lambda = 1.0. The control constantly fluctuates back and forward between the “slightly too lean” and “slightly too rich” states.   Note t  Note on display field 4: t  For a display value of 0.3, the engine obtains a very rich mixture from the ACF system. The lambda control must reduce the injection rate to 30%. t  For a display value of 1.0, an ideal mixture is supplied by the ACF system (there is no lean or enrichment necessary) or the ACF valve is closed (adaptation: display group 008, display field 4). t  For a display value of 1.01 to 1.2, the mixture from the ACF system is too lean. The lambda control must enrich.

Voltage of the lambda probe Uλ in mV A: Lambda probe voltage high t  rich mixture (fuel surplus or air shortage) t  high CO value B: Lambda probe voltage low t  lean mixture (fuel shortage or air surplus) t  low CO value Display group 008, Lambda learned values:

Read measured value block 8 →				← Readout on display
2.0...5.0 ms	-10,0...10,0 %	-8,0...8,0 %	TV active or TV not active or λ adaptation
1	2	3	4	← Display field
				“TV active” means, that the activated charcoal filter system solenoid valve 1 is pulsed (6 to 16 min) “TV not active” means, that the activated charcoal filter system solenoid valve 1 is closed constantly (1 min) “λ adaptation” means the correction of the voltage curve displacement resulting from the lambda probe ageing.
			Lambda learned value at partial load (multiplicative)
		Lambda learned value at idling speed (additive)
	Injection period

Test table - Display group 008

Display field	Display -V.A.G 1552 -	Fault cause	Rectifying fault
1		see test table - display group 002, display field 3 → Chapter
2 and 3	low lambda learned values	t  low lambda idle learned values at normal lambda partial load learned values: Oil dilution (higher fuel content in the oil) possible	–  Disappears after driving on motorway or changing oil. –  Display group 007, display field 2.
		t  Injection valve leaks	–  Test injectors for vehicles ? 07.97 → Chapter or for vehicles 08.97? → Chapter.
		t  Fuel pressure too high	–  Check fuel pressure → Chapter.
		t  Solenoid valve for activated charcoal filter constantly open	–  Check -N80 - → Chapter.
		t  Air mass meter faulty -G70-	–  Check -G70 - → Chapter.
		t  Lambda probe heating defective or lambda probe dirty	–  Check lambda probe heater → Chapter.
	high lambda initialisation values	t  high lambda idling learned values at less high lambda partial load learned values: Unmetered air in intake manifold region possible	–  Inspect intake system for leaks → Chapter.
		t  Injection valve blocked	–  Testing injection valves → Chapter, → Chapter.
		t  Air mass meter faulty -G70-	–  Test air mass meter -G70- for vehicles ? 07.97 → Chapter or for vehicles 08.97? → Chapter.
		t  Fuel pressure too low	–  Testing fuel pressure regulator and holding pressure → Chapter.
		t  Unmetered air between air mass meter -G70- and throttle valve	–  Eliminate cause.
		t  Unmetered air at the manifold gasket
		t  Lambda probe heating defective or lambda probe dirty	–  Check lambda probe heater → Chapter.

Note t  Re display field 2 and 3: t  Low readouts indicate that the engine is running too rich and the lambda control therefore produces a leaner mixture. t  add = additive - The effect of the fault (e.g. unmetered air) becomes increasingly less as engine speed rises. In the case of an additive initialisation value the injection period is changed by a fixed rate. This rate is independent of the basic injection period. t  mul = multiplicative - The effect of the fault (e.g. faulty injector) becomes greater as engine speed rises. The multiplicative learned value is a percentage change in the injection period. This change is dependent on the basic injection period. t  High readouts mean that the engine is running too lean and the lambda control therefore produces a richer mixture. t  If the engine control unit is dead all initialisation values are reset. Display group 009 - Lambda learned values:

Read measured value block 9 →				← Readout on display
XXX rpm	- 10... + 10 %	0...1.0 V	- 10... + 10 %
1	2	3	4	← Display field
				Lambda learned value at idling speed (additive)
			Lambda probe voltage
		Lambda regulator
	Idling speed		? 07.97 : 760 to 840 rpm 08.97 ? : 760 to 880 rpm

Display group 010 - Lambda learned values:

Read measured value block 10 →				← Readout on display
0....99 %	0,3...1,25	3...321) -5...452)	0,00...0,30
1	2	3	4	← Display field
				Activated charcoal filter - rinse rate (ACF): l  for value “0.00” nothing is supplied from the ACF system l  for value “0.30” 30% of the inducted air mass is from the ACF system
			Volumetric efficiency of activated charcoal filter system: l  for value -3 or -5, there are no petrol vapours in the activated charcoal filter system l  for value 32 or 45, the activated charcoal filter system is filled up with petrol vapours
		Lambda correction factor for active fuel tank ventilation
	On/Off ratio of solenoid valve 1 for activated charcoal filter (ACF)

1) ? 07.97 2) 08.97 ?   Note t  to display group 10: t  The engine control unit determines via the activated charcoal filter system solenoid valve 1 how much fuel is supplied to the engine from the activated charcoal filter system. If now the solenoid value continues to be closed (low space ratio) at a high volumetric efficiency of the activated charcoal filter system, in order to maintain the specified rinse rate, a change of the lambda correction factor shows itself as a reaction of the lambda control. If this reaction is lower than expected, because fuel vapours from the fuel tank have increased the volumetric efficiency in the meantime, thus the engine control unit calculates a higher volumetric efficiency. t  Checking the fuel tank venting → Chapter. t  In idle, the engine can only process a determined maximum fuel vapour amount from the activated charcoal filter system. Therefore in idle the opening of the activated charcoal filter system solenoid valve 1 is limited. At partial load, the space ratio can increase to 99%. t  The influence of the activated charcoal filter system can be analysed through the comparison of the display value during the “basic setting” (solenoid valve 1 closed) and during “Read measured valued block” (solenoid valve 1 approx. 220 to 900 seconds open/ approx. 70 seconds closed). t  It can be switched back and forward between the function 04 “Basic setting” and the function 08 “Read measured value block” by pressing the buttons 4 and 8 at -V.A.G 1552- or -V.A.G 1551-.   Note t  Re display field 1: t  The solenoid valve 1 for activated charcoal filter system (-N80-) is pulsed using the lambda control. It remains open at an interval of approx. 220 to 900 seconds (tank ventilation is carried out) and closed at approx 70 seconds (no tank ventilation). During the approximative 70 seconds, the lambda control initialises the operating ratios without the variation due to fuel vapours from the activated charcoal filter system. t  Space ratio 0% means, the activated charcoal filter system solenoid valve 1 is closed. The solenoid valve 1 is fully open for a 99% space ratio.   Note t  Re display field 2: t  If a very rich mixture comes from the activated charcoal filter system, the lambda control must be lean. This lean can be up to 0.6. This means that in this case the lambda control must reduce the injection rate to 40%. t  For a display value of 1.0 (lambda control in neutral range, also without correction factor) an ideal mixture comes from the activated charcoal filter system (no lean or enrichment is necessary) or the solenoid valve 1 is closed → display field 1. t  For a display value of 1.01 to 1.25, the mixture from the ACF system is too lean. The lambda control must enrich. Display group 011, fuel consumption:

Read measured value block 11 →				← Readout on display
XXX rpm	1.0...2.5 ms	0 km/h	0.5...1.5 l/h
1	2	3	4	← Display field
				Fuel consumption: the display specified value applies only for idle without load due to auxiliary equipment (automatic gearbox, air conditioning system, generator, gear pump).
			Driving speed
		Engine load
	Idling speed		? 07.97 : 760 to 840 rpm 08.97 ? : 760 to 880 rpm

Note t  Re display field 2: t  The maximum engine load decreases approximately 10% for each 1000 m above sea level. t  The maximum engine load decreases approximately 10% at very high outside temperatures. t  When driving at full load, the following values must be reached: - at 4000 rpm approx. 7.5 ms, at 6000 rpm approx. 6.5 ms. Display group 012, fuel consumption:

Read measured value block 12 →				← Readout on display
XXX rpm	10...14.5 V	0.5...1.5 l/h	XX.X° BTDC
1	2	3	4	← Display field
				Ignition angle	? 07.97 : 3 to 12° b. TDC (b. TDC) 08.97 ? : 6 to 12° b. TDC (b. TDC)
			Fuel consumption - see display group 011, display field 4
		Battery voltage - see display group 003, display field 2
	Idling speed		? 07.97 : 760 to 840 rpm 08.97 ? : 760 to 880 rpm

Display group 013, knock control:

Read measured value block 13 →				← Readout on display
0...15° KW	0...15° KW	0...15° KW	0...15° KW
1	2	3	4	← Display field
				Ignition angle relief cylinder 4 through knock control
			Ignition angle relief cylinder 3 through knock control
		Ignition angle relief cylinder 2 through knock control
	Ignition angle relief cylinder 1 through knock control

Note t  to display group 013: t  The knock control is active from an engine load of more than 40%. t  If an engine load of 40% is exceeded, the current retardation values of the ignition angle are displayed. If it is below, the last used values are constantly displayed. t  If knocking can be heard without any retardation of the ignition angle detectable, increase engine speed for 5 seconds to more than 3500 rpm in order to activate the knock sensor fault detection (diagnosis). t  If a retardation value of the ignition angle for a cylinder clearly differs from the others, the following faults are possible: -loose ancillaries--corrosion at the plug connection--engine damage (e. g. oil combustion in case of defective piston)- t  If there are larger retardation values of the ignition point for all cylinders, the following faults are possible: -corrosion at the plug connection--tightening torque for knock sensor (20 Nm) n.o.k--Line interruption--knock sensor defective--loose ancillaries- Display group 014, knock control:

Read measured value block 14 →				← Readout on display
0...6800 rpm	0...10.0 ms	0...15° KW	0...15° KW
1	2	3	4	← Display field
				Ignition angle relief cylinder 2 through knock control
			Ignition angle relief cylinder 1 through knock control
		Engine load (injection time per rotation)
	Engine speed

Note t  to display group 014: t  With this display group, the ignition angle relief for cylinder 1 and 2 can be checked for exact speed and load ratios. t  Causes for ignition angle relief: Display group 013. Display group 015, knock control:

Read measured value block 15 →				← Readout on display
0...6800 rpm	0...10.0 ms	0...15° KW	0...15° KW
1	2	3	4	← Display field
				Ignition angle relief cylinder 4 through knock control
			Ignition angle relief cylinder 3 through knock control
		Engine load (injection time per rotation)
	Engine speed

Note t  to display group 015: t  With this display group, the ignition angle relief for cylinder 3 and 4 can be checked for exact speed and load ratios. t  Causes for ignition angle relief: Display group 013. Display group 016, knock control: (idle)

Read measured value block 16 →				← Readout on display
0.4...2.0 V	0.4...2.0 V	0.4...2.0 V	0.4...2.0 V
1	2	3	4	← Display field
				Knock sensor of cylinder 4
			Knock sensor of cylinder 3
		Knock sensor of cylinder 2
	Knock sensor of cylinder 1

Note t  If a difference of more than 50% exists between the smallest and largest knock sensor signal, the cause may be corrosion at the plug connection. t  If no fault is found when electrically testing the knock sensor, the wiring and the plug connection, inspect the engine for loose ancillaries. Display group 013. t  The displayed signal voltage of the knock sensors can reach values up to 5.1 volt at high speeds and loads. Display group 017, CAT heating:

Read measured value block 17 →				← Readout on display
0...6800 rpm	1.0...2.5 ms	0...100 %	XX.X° BTDC
1	2	3	4	← Display field
				Ignition angle
			Overview of energy consumption for CAT heating
		Engine load (injection time per crankshaft rotation)
	Engine speed

Note t  to display group 017: t  In order to bring the catalytic converter after cold start as fast as possible to operating temperature, the speed is increased at idle and the ignition angle is adjusted to late. The ignition angle late adjustment is only effective in the partial load range. t  This function for fast heating up of the catalytic converter is effective at starting temperatures of - 9 to + 39°C. t  The function is aborted in case of one of the following conditions: -Engine speed above 4000 rpm--Engine load greater than 7.0 ms--Fault in the fault memory for air mass meter and coolant temperature sender --Energy consumption above 1.0--Speed above 55 km/h--Height correction factor less than -20% (display group 018)- t  As soon as the function is aborted, the display for the energy consumption remains stable and is reset during the next start. Display group 018, height adaptation:

Read measured value block 18 →				← Readout on display
XXX rpm	1.0...2.5 ms	0.5...3 ms	-50...+15 %
1	2	3	4	← Display field
				Level correction factor
			Engine load from throttle valve angle
		Engine load from air mass meter see display group 001, display field 2
	Idling speed		? 07.97 : 760 to 840 rpm 08.97 ? : 760 to 880 rpm

Note t  to display group 018: t  The engine control unit compares the load signal of the air mass meter with a load value, which is calculated from the throttle valve angle and the speed. The variation of both values results in the height correction factor. t  -30% corresponds to an air pressure of approx. 70 kPa (30% below 100 kPa). t  No height correction is required for an altitude of about 400 m above sea level and normal weather conditions. t  At sea level of 0 m, the height correction factor is about 0%. t  At sea level of approx. 2000 m, the height correction factor is about -20%. t  The following factors are influenced by the height adaptation: -Start quantity requirement--Intake manifold pulsation compensation-. Display group 019, torque reduction: (automatic gearbox) ? 07.97

Read measured value block 19 →				← Readout on display
0...6800 rpm	ms	X 1 X	°KW
1	2	3	4	← Display field
				Ignition angle
			Operating condition: X 1 X = no gearbox intervention signal X 0 X = gearbox intervention signal X = Display without meaning
		Engine load
	Engine speed

Note t  to display group 019: t  With this display group, it can be analysed if the gearbox intervention signal comes from the gearbox control unit in the engine control unit. t  Based on the short signal, the ignition angle relief cannot always be detected by -V.A.G 1552- and thus also not displayed. Display group 019, additional signals: Power steering pressure switch, ignition angle relief and clutch pedal switch 08.97 ?

Read measured value block 19 →				← Readout on display
0...6800 rpm	0...10.00 ms	xxxx_x	°KW
1	2	3	4	← Display field
				Ignition angle
			Additional signals 0xxx_x = Power steering pressure switch xx0x_x = Ignition angle relief active xxx0_x = Clutch pedal switch active
		Engine load
	Engine speed

Note t  to display group 019: t  With this display group, different additional signals can be analysed. t  PAS pressure switch t  Clutch pedal switch t  Ignition angle relief during gearshifts Display group 020, operating conditions:

Read measured value block 20 →				← Readout on display
XXX rpm	Neutral driving position ON	A/C High A/C Low	Compr. ON Compr. OFF
1	2	3	4	← Display field
				AC compressor ON/OFF vehicles not fitted with air conditioning system always indicate “Compr. OFF”
			Air conditioning system High = high heat or cooling power output Low = low heat or cooling power output vehicles not fitted with air conditioning system always indicate “A/C-Low”
		Selector lever position, neutral or driving position ON vehicles fitted with manual gearbox always indicate “Neutral”
	Idling speed		? 07.97 : 760 to 840 rpm 08.97 ? : 760 to 880 rpm

Display group 021, operating condition of the lambda control:

Read measured value block 21 →				← Readout on display
XXX rpm	1.0...2.5 ms	XXX °C	Reg. λ-off. Reg. λ-on.
1	2	3	4	← Display field
				Lambda control ON/OFF
			Coolant temperature
		Engine load - see display group 001, display field 2
	Idling speed		? 07.97 : 760 to 840 rpm 08.97 ? : 760 to 880 rpm

Note t  to display group 021: t  The lambda control is switched on by the engine control unit depending upon the engine temperature and the intake air temperature. t  At a start temperature below 5°C (intake air temperature), the lambda control is switched on by the engine control unit only as of a cooling temperature of 55°C. t  At a start temperature above 15°C (intake air temperature), the lambda control is on if the probe operation is detected. t  If the lambda control is switched off, the engine runs map-controlled. Display group 023, adaptation of throttle valve control unit: ? 07.97

Read measured value block 23 →				← Readout on display
01000000	73...97 %	54...85 %	6...43 %
1	2	3	4	← Display field
				max limit of throttle valve positioner -V60-
			Emergency limit of throttle valve positioner - V60-
		min. limit of throttle valve positioner - V60-
	Initialisation need display

Note t  Re display field 1: t  If the display nominal value is not achieved, adapt engine control unit to the throttle valve control unit -J338- → Chapter. t  regarding display fields 2, 3 and 4: t  The initialised limit values are displayed at the last basic setting. t  regarding display fields 1, 2, 3 and 4: t  If the display nominal value is not reached again after performing the basic setting, check the wiring for open circuit or short circuit as well as plug connections for soiling or corrosion before replacing the throttle valve control unit.

X	X	X	X	X	X	X	X	Meaning of 8-digit display
								1 =	no meaning
								2 =	Learning process min. limit of throttle valve positioner sender - G127- value “0” = learning process performed, learning process o.k. value “1” = learning process not performed, learning process n.o.k.
								3 =	Learning process max. limit of throttle valve positioner sender - G127- value “0” = learning process performed, learning process o.k. value “1” = learning process not performed, learning process n.o.k.
								4 =	Learning process min. limit of throttle valve potentiometer -G69- value “0” = learning process performed, learning process o.k. value “1” = learning process not performed, learning process n.o.k.
								5 =	Learning process max. limit of throttle valve potentiometer -G69- value “0” = learning process performed, learning process o.k. value “1” = learning process not performed, learning process n.o.k.
								6 =	no meaning
								7 =	Balance throttle valve potentiometer -G69- with throttle valve positioner sender -G127- value “0” = Balance must be performed value “1” = Balance performed, balance o.k.
								8 =	no meaning

Display group 023, adaptation of throttle valve control unit: 08.97 ?

Read measured value block 23 →				← Readout on display
100000	73...97 %	54...85 %	6...43 %
1	2	3	4	← Display field
				max limit of throttle valve positioner -V60-
			Emergency limit of throttle valve positioner - V60-
		min. limit of throttle valve positioner - V60-
	Initialisation need display

Note t  Re display field 1: t  If the display nominal value is not achieved, adapt engine control unit to the throttle valve control unit -J338- → Chapter. t  regarding display fields 2, 3 and 4: t  The initialised limit values are displayed at the last basic setting. t  regarding display fields 1, 2, 3 and 4: t  If the display nominal value is not reached again after performing the basic setting, check the wiring for open circuit or short circuit as well as plug connections for soiling or corrosion before replacing the throttle valve control unit.

X	X	X	X	X	X	Meaning of 6-digit display
						1 =	Learning process min. limit of throttle valve positioner sender -G127- value “0” = learning process performed, learning process o.k. value “1” = learning process not performed, learning process n.o.k.
						2 =	Learning process max. limit of throttle valve positioner sender -G127- value “0” = learning process performed, learning process o.k. value “1” = learning process not performed, learning process n.o.k.
						3 =	Learning process min. limit of throttle valve potentiometer -G69- value “0” = learning process performed, learning process o.k. value “1” = learning process not performed, learning process n.o.k.
						4 =	Learning process max. limit of throttle valve potentiometer -G69- value “0” = learning process performed, learning process o.k. value “1” = learning process not performed, learning process n.o.k.
						5 =	no meaning
						6 =	Balance throttle valve potentiometer -G69- with throttle valve positioner sender -G127- value “0” = Balance must be performed value “1” = Balance performed, balance o.k.

Display group 024, knock control:

Read measured value block 24 →				← Readout on display
0...6800 rpm	0...10.00 ms	20°a. TDC 42° b. TDC	0...36.0 °KW
1	2	3	4	← Display field
				Total of the ignition angle relief cylinder 1 to 4
			Ignition angle
		Engine load
	Engine speed

Note t  to display group 024: t  As soon as knocking effects are detected, the knock control of the ignition angle must be deactivated, in order to avoid engine damage. t  The exhaust temperature is increased by the ignition angle relief. There is a risk of overheating for the catalytic converter. t  An ignition angle relief of e.g. 3° KW for all cylinders has the same effect as an ignition angle relief of 12° KW for only one cylinder. t  In order to prevent this overheating, it is enriched at full load as of a total relief of approx. 10° KW, in order to decrease the exhaust temperature. Display group 025; control of the camshaft adjustment: ? 07.97

Read measured value block 25 →				← Readout on display
Idling	- 30...+ 30 ° KW	X XX	- 3....+ 22 ° KW
1	2	3	4	← Display field
				active camshaft adjustment angle camshaft in normal position = -3.0 to 3.0° KW camshaft in switched position = 15.0 to 22.0° KW
			Operating condition: Camshaft adjustment
		Setting tolerance of phase sender (Hall sender)
	Operating position

Meaning of the digits in the 3-digit display, display field 3 - operating condition

X					X	X	Meaning
								Value “0” = condition not fulfilled, actuation not active value “1” = condition fulfilled, actuation active
							Camshaft adjustment (1 = “early adjustment”, power output position)
							no meaning
							not assigned
							no meaning

Note t  Re display field 4: t  For the adjustable camshaft there are two positions - camshaft adjustment not active or camshaft adjustment active. In order to achieve the switched position of the camshaft, accelerate the vehicle in the 2nd gear with the accelerator pedal depressed when driving slowly (approx. 1000 rpm). In case the actuation of the camshaft adjustment is active -see display field 3-, it can be detected in the display field 4 if an adjustment of the camshaft has taken place (feedback). If the adjustment is not active, check whether full load is detected (the camshaft adjustment is only active at full load!). Display group 025; control of the camshaft adjustment, variable intake manifold changeover: 08.97 ?

Read measured value block 25 →				← Readout on display
Idling	- 30...+ 30 ° KW	X XX	- 3....+ 22 ° KW
1	2	3	4	← Display field
				active camshaft adjustment angle camshaft in normal position = -3.0 to 3.0° KW camshaft in switched position = 15.0 to 22.0° KW
			Operating condition: Variable intake manifold changeover Camshaft adjustment
		Setting tolerance of phase sender (Hall sender)
	Operating position

Note t  Re display fields 3 and 4: t  For the adjustable camshaft there are two positions - camshaft adjustment not active or camshaft adjustment active. In order to achieve the switched position, move the vehicle out of its stationary position to the 1st gear. The actual position of the adjustable camshaft is displayed in the display field 4. In case the actuation of the camshaft adjustment is active -see display field 3-, it can be detected in the display field 4 if an adjustment of the camshaft has taken place (feedback). -Camshaft in normal position = -3.0 to 3.0° KW--camshaft in switched position = 15.0 to 22.0° KW- t  If a value between 4.0° KW and 14.0° KW is displayed in the display field during a test drive, the camshaft adjustment magnetic valve switches the oil pressure to the mechanical camshaft adjuster, however this one cannot reach its final position (e.g. due to resistance). t  Test camshaft adjustment: → 1.8 l/92 kW Engine, Mechanical Components; Rep. Gr.15. Meaning of the digits in the 3-digit display, display field 3 - operating condition

X					X	X	Meaning
								Value “0” = condition not fulfilled, actuation not active value “1” = condition fulfilled, actuation active
							Camshaft adjustment (1 = “early adjustment”, power output position)
							Variable intake manifold changeover (1 = long suction path, torque position)
							not assigned
							no meaning

Display group 026; control of the camshaft adjustment: ? 07.97

Read measured value block 26 →				← Readout on display
0...4500 rpm	0...10.00 ms	X XX	- 3....+ 22 ° KW
1	2	3	4	← Display field
				active camshaft adjustment angle camshaft in normal position = -3.0 to 3.0° KW camshaft in switched position = 15.0 to 22.0° KW
			Operating condition: Camshaft adjustment
		Engine load - see display group 001, display field 2
	Engine speed

Note t  Re display field 4: t  For the adjustable camshaft there are two positions - camshaft adjustment not active or camshaft adjustment active. In order to achieve the switched position of the camshaft, accelerate the vehicle in the 2nd gear with the accelerator pedal depressed when driving slowly (approx. 1000 rpm). In case the actuation of the camshaft adjustment is active -see display field 3-, it can be detected in the display field 4 if an adjustment of the camshaft has taken place (feedback). If the adjustment is not active, check whether full load is detected (the camshaft adjustment is only active at full load!). Meaning of the digits in the 3-digit display, display field 3 - operating condition

X					X	X	Meaning
								Value “0” = condition not fulfilled, actuation not active value “1” = condition fulfilled, actuation active
							Camshaft adjustment (1 = “early adjustment”, power output position)
							no meaning
							not assigned
							no meaning

Display group 026; control of the camshaft adjustment, variable intake manifold changeover: 08.97 ?

Read measured value block 26 →				← Readout on display
0...4500 rpm	0...10.00 ms	X XX	- 3....+ 22 ° KW
1	2	3	4	← Display field
				active camshaft adjustment angle camshaft in normal position = -3.0 to 3.0° KW camshaft in switched position = 15.0 to 22.0° KW
			Operating condition: Variable intake manifold changeover Camshaft adjustment
		Engine load - see display group 001, display field 2
	Engine speed

Meaning of the digits in the 3-digit display, display field 3 - operating condition

X					X	X	Meaning
								Value “0” = condition not fulfilled, actuation not active value “1” = condition fulfilled, actuation active
							Camshaft adjustment (1 = “early adjustment”, power output position)
							Variable intake manifold changeover (1 = long suction path, torque position)
							not assigned
							no meaning

Note t  Re display field 4: t  For the adjustable camshaft there are two positions - camshaft adjustment not active or camshaft adjustment active. In case the camshaft adjustment is active -see display field 3-, it can be detected in the display field 4 if a camshaft adjustment has taken place (feedback).