SEAT Workshop Service and Repair Manuals

    1)    Up-to-date specifications:

=> Exhaust emissions test binder

Notes on display zone 2:

• ◆ When driving at full load the following minimum values must be obtained:
  At 4000 rpm approx. 6.5 ms
  At 6000 rpm approx. 6.0 ms
• ◆ Above 3000 m above sea level and at very high ambient temperatures the maximum engine load drops dramatically.

Evaluating display group 1, display zone 1 - Engine speed (idling speed)

Evaluating display group 1, display zone 2 - Engine load

Evaluating display group 1, display zone 3 - Throttle valve angle

Note:

Display values must be approx. 80...90 <°when accelerator pedal is depressed fully. The reduced output is perceptible when the display does not reach 80 <°.

Evaluating display group 2, display zone 3 - Injection period

Evaluating display group 2, display zone 4 - Air mass drawn in

Note on display zone 4:

• ◆ Displayed is the air mass measured by the air mass meter.
• ◆ In emergency running caused by a fault on the throttle valve control part the engine runs without idling stabilisation at an increased idling speed (approx. 1000...1300 rpm) via the emergency running gap. In this case the air throughput is approx. 4.5...5.5 g/s.
• ◆ The replacement value in g/s from throttle valve potentiometer will be displayed if the engine control unit detects a fault on the air mass meter.

Note on display zone 3:

The engine control unit will use the intake air temperature as a replacement value for an engine start (start temperature - replacement value) as soon as there is a fault stored in the fault memory, which affects the coolant temperature sender (G62). The temperature then rises according to a model stored in the control unit. When the engine has reached normal working temperature a fixed replacement value will be displayed after a certain period. This fixed value is also dependent upon the intake air temperature.

Note on display zone 4:

The total temperature range is given as the specification. The displayed value must be above ambient temperature.

Evaluating display group 3, display zone 2 - Control unit voltage supply

Evaluating display group 3, display zone 3 - Coolant temperature

Evaluating display group 3, display zone 4 - Intake air temperature

Note on display zone 1:

With the accelerator pedal floored the display value is approx. 80...90 <°.

Notes on display zones 2 and 3:

• ◆ Displayed is how far the idling stabilisation has "learnt" and moved away from the predetermined design average. If the engine is new the value will be in the positive range due to the high engine friction, and when run-in in the negative range. Values at the lower tolerance limit in conjunction with a value which is too low in display group 5, display zone 3 indicates unmetered air.

• ◆ The value displayed is not measured by the air mass meter, but calculated from the throttle valve potentiometer information.
• ◆ Display zone 3 will always show 0.00 g/s on vehicles with a manual gearbox.

Note on display zone 4:

The following operating conditions are displayed:

• ◆ Idling speed
• ◆ Part throttle
• ◆ Overrun
• ◆ Enrichment (full throttle enrichment)

Evaluating display group 4, display zone 2 - idling air mass learning value

Note on display zone 1:

The actual engine speed in steps of 10 is displayed (max. 2550 rpm).

Note on display zone 2:

The specified engine speed from engine control unit (calculated in control unit ) is displayed. In exceptional cases the idling speed can be matched => Page 24-85. The idling speed figures with gear selected are then automatically modified.

Notes continued:

Notes on display zone 3:

• ◆ The required idling air mass at a constant speed changes due to the changes in the load ratios at idling.
• ◆ Displayed is the change in the idling air mass in %. As soon as the idling stabilisation learning process has compensated for this change, the average value is set again. The amount of deviation from the average value depends upon the level of the load change (e.g. caused by switching electric consumers on or off).
• ◆ After each time the idling switch closes the learning process is performed in small steps. More steps are required for large deviations. Therefore the accelerator pedal must be depressed briefly (throttle burst) at intervals of approx. 20 seconds. Using this method a further step of the learning process is performed each time.
• ◆ The "learnt" deviation then appears in display group 4, display zone 2. If the learnt values in display group 4, display zone 2 have moved to the limit the value for the idling regulator remains outside the tolerance.
• ◆ Stop values: -1.10 or +1.10 g/s

Notes on display zone 3:

• ◆ The display must fluctuate around 0. If constant 0 is displayed, the Lambda regulation has switched from regulation to control, because there is a fault in the Lambda regulation. Interrogate fault memory => Page 01-10.
• ◆ Operating condition Lambda regulation: Display group 21, checking display zone 4 => Page 01-112.

Evaluating display group 6, display zone 3 - Lambda regulator

Note on display zone 2:

• ◆ The voltage signal "rich mixture (low level of residual oxygen)" is approx. 0.7...1.0 V.
• ◆ The voltage signal "lean mixture (high level of residual oxygen)" is approx. 0.0...0.3 V.
• ◆ When changing from "rich" to "lean" and back again (λ = 1.0) the voltage jump will change from 0.7...1.0 V to 0.0...0.3 V or back again.
• ◆ Due to the steep voltage jumps the Lambda control cannot keep the ideal mixture composition λ = 1.0 constant. The control fluctuates constantly between conditions "slightly too lean" and "slightly too rich".
• ◆ The displayed value must temporarily drop below 0.3 V and exceed 0.6 V. Displayed values below 0.45 V signifies lean, above 0.45 V rich.

→ Lambda probe voltage Uλ in mV

A: High Lambda probe voltage

• ◆ Rich mixture (excess of fuel or shortage of air)
• ◆ Higher CO value

B: Low Lambda probe voltage

• ◆ Lean mixture (shortage of fuel or excess air)
• ◆ Lower CO value

Noes on display zones 2 and 3:

Low values indicate that the engine is running too rich and therefore the Lambda regulation is leaning the mixture.

• ◆ High values indicate that the engine is running too lean and therefore the Lambda regulation enriches the mixture.
• ◆ If there is no voltage supply to the control unit all the values learnt will be cancelled.
• ◆ add = additive - The effects of the fault (e.g. unmetered air) will reduce as the engine speed increases. The injection period will be modified by a fixed amount for additive learnt values. This amount is not dependent upon the basic injection period.
• ◆ mul = multiplicative - The effects of the fault (e.g. faulty injector) will increase as the engine speed increases. A multiplicative learnt value is a proportional change to the injection period. This change is dependent on the basic injection period.

Evaluating display zone 8, display zones 2 and 3 - Lambda learnt values

Note on display zone 3:

• ◆ The voltage signal "rich mixture (low level of residual oxygen)" is approx. 0.7...1.0 V.
• ◆ The voltage signal "lean mixture (high level of residual oxygen)" is approx. 0.0...0.3 V.
• ◆ When changing from "rich" to "lean" and back again (λ = 1.0) the voltage jump will change from 0.7...1.0 V to 0.0...0.3 V or back again.
• ◆ Due to the steep voltage jumps the Lambda control cannot keep the ideal mixture composition λ = 1.0 constant. The control fluctuates constantly between conditions "slightly too lean" and "slightly too rich".
• ◆ The displayed value must temporarily drop below 0.3 V and exceed 0.6 V. Displayed values below 0.45 V signifies lean, above 0.45 V rich.

Note on display zone 4:

Low values indicate that the engine is running too rich and therefore the Lambda regulation is leaning the mixture.

• ◆ High values indicate that the engine is running too lean and therefore the Lambda regulation enriches the mixture.
• ◆ If there is no voltage supply to the control unit all the values learnt will be cancelled.

Evaluating display group 9, display zone 3 - Lambda probe voltage

Notes on display group 10:

• ◆ The engine control unit specifies the amount of fuel vapours which are fed into the engine, via the activated charcoal filter solenoid valve 1 (N80). If the activated charcoal filter has a high charge level and the solenoid valve 1 must remain close to maintain prescribed purge rate (low duty cycle), the reaction of the Lambda regulation will be seen by a change in the Lambda correction factor. If this reaction is lower than expected, because in the meantime the charge level has been increased due to the fuel vapours from the fuel tank, the control unit will from this calculate a higher charge level.
• ◆ Check fuel tank breather:

=> Repair group 20; Activated charcoal filter system; Checking fuel tank breather

Notes on display zone 1:

• ◆ When the Lambda regulation commences the activated charcoal filter solenoid valve 1 (N80) is pulsed at intervals of approx. 220...900 seconds (tank venting is performed) and switched off for approx. 70 seconds (no tank venting).
  During the 70 seconds the Lambda regulation learns the operating conditions without the deviation from fuel vapours from the activated charcoal filter.
• ◆ Duty cycle 0 % indicates that the activated charcoal filter solenoid valve 1 is closed. For a duty cycle of 99 % the solenoid valve 1 is fully open.
• ◆ At idling the engine can only accept a certain maximum amount of fuel vapours from the activated charcoal filter system. Therefore the activated charcoal filter solenoid valve 1 opening is limited at idling. The duty cycle can rise to 99 % at part throttle and full throttle.
• ◆ The influence of the activated charcoal filter system can be assessed by comparing the displayed values during the "Basic setting" (solenoid valve 1 closed) and during "Read measured value block" (solenoid valve 1 approx. 220...900 seconds open/approx. 70 seconds closed).
• ◆ It is possible to switch between function 04 "Basic setting" and function 08 "Read measured value block" by pressing keys 4 and 8 on V.A.G 1551/1552.

Notes on display zone 2:

• ◆ If a very rich mixture is being given off by the activated charcoal filter system, it must be leaned by the Lambda regulation. This leaning can be up to 0.6. This means in this case that the Lambda regulation must reduce the injection rate by 40 %.

Notes continued:

• ◆ If the displayed value is 1.0 (Lambda regulation in neutral range, which means no correction factor) either an ideal mixture is coming from the activated charcoal filter system (it is not necessary to alter the mixture) or the solenoid valve 1 is closed =>display zone 1.
• ◆ If the displayed value is between 1.01...1.25 the mixture coming from the activated charcoal filter system is too lean. Therefore the Lambda regulation must enrich the mixture.

Notes on display zone 3:

• ◆ -3 indicates that there are no fuel vapours in activated charcoal filter.
• ◆ 32 indicates that the activated charcoal filter is filled completely with fuel vapours.

Notes on display zone 4:

• ◆ Indicated is the portion by volume of the activated charcoal filter system in relation to the complete volume drawn in.
• ◆ 0.00 indicates nothing has been fed in from the activated charcoal filter system (solenoid valve 1 closed).
• ◆ 0.30 indicates that 30 % of the intake air mass comes from the activated charcoal filter system.

Note on display zone 3:

Checking speed signal => Page 24-117

Notes on display zone 4:

• ◆ The specification is only valid for an idling speed which is not loaded due to ancillaries (e.g. automatic gearbox, air conditioning/heating, alternator, P.A.S. pump).
• ◆ ltr./100 km not suitable for fuel consumption measurement.