Audi Workshop Service and Repair Manuals

Display group 08, lambda learned values

1) Engine code ADP 2) Engine code ADR 3) Engine code AEB

Test table, Display group 08

Note on Display zones 2 and 3:

Low values mean that the engine is running too rich, and the lambda control is compensating by leaning out the mixture.

Note on Display zones 2 and 3:

• ◆ High learned values mean that the engine is running too lean, and therefore the lambda control is compensating by enriching the mixture.
• ◆ If there is no voltage in the control unit, all the learned values will be reset.
• ◆ `Additive' means that the impact of the fault decreases as the engine speed increases (e.g. unmetered air).
• ◆ `Multiplicative' means that the impact of the fault increases as the engine speed increases (e.g. injector fault).

Note on Display zone 4:

During the λ-adaptation the lambda control "learns" the operating conditions without the deviation due to the fuel vapours from the activated charcoal filter (ACF valve closed).

Display group 09, lambda learned values

1) Engine code ADP 2) Engine code ADR 3) Engine code AEB

Note on Display zone 1:

=>Display group 01, Display zone 1

Note on Display zone 2:

=>Display group 06, Display zone 3

Note on Display zone 3:

=>Display group 07, Display zone 2

Note on Display zone 4:

=>Display group 08, Display zone 2

Display group 10, tank breather

Note on Display zone 1:

=>Display group 07, Display zone 3

Note on Display zone 2:

=>Display group 07, Display zone 4

Note on Display zone 3:

At a value of -3 there are no fuel vapours in the ACF canister.

At a value of +30 the ACF canister is completely full of fuel vapours.

Note on Display zone 4:

The display shows the percentage by volume of the activated charcoal filter system referenced to the total intake volume.

At a value of 0.00 nothing is delivered by the ACF system (solenoid valve closed).

At a value of 0.30, 30 % of the intake air mass comes from the ACF system.

Display group 11, fuel consumption:

This display group can be used to assess the dependency of fuel consumption on engine speed, engine load and vehicle speed.

1) Engine code ADP 2) Engine code ADR 3) Engine code AEB

Notes on Display zone 2:

• ◆ The maximum engine load decreases by about 10 % for every 1000 m above sea level.
• ◆ The maximum engine load also falls by up to 10 % at very high ambient temperatures.

Note on Display zone 4:

The specified readout value only applies to idling without any ancillary loads (autom. gearbox, air conditioner/heater, alternator, power steering pump)

The values when driving at full throttle should not be less than the following:

at 4000 rpm at 6000 rpm

• ◆ Engine code ADP: 7.0 ms 6.1 ms
  ADR: 7.5 ms 6.5 ms
  AEB: 6.5 ms 6.0 ms

Display group 12, fuel consumption during idling

1) Engine code ADP 2) Engine code ADR 3) Engine code AEB

Note on Display zone 1:

=>Display group 01, Display zone 1

Note on Display zone 2:

=>Display group 03, Display zone 2

Note on Display zone 3:

=>Display group 11, Display zone 4

Note on Display zone 4:

=>Display group 01, Display zone 4

Display group 13, knock control

Notes:

• ◆ Knock control is active over the entire engine speed range from a 3 ms engine load upwards.
  When a 3 ms engine load is exceeded the current values for the ignition timing retardation are displayed. If the load is below this value then the ignition timing retardation is cancelled again.
• ◆ If there is audible knocking but no retardation of the ignition timing then increase the engine speed to above 3000 rpm for 5 seconds to initiate the knock sensor fault detection (diagnosis).
• ◆ If the ignition timing retardation value differs greatly from one cylinder to the others then the following faults are possible:
  - Loose ancillaries
  - Corrosion on the plug connector
  - Engine damage (e.g. oil combustion due to a defective piston)
• ◆ If the ignition timing retardation values for all the cylinders are high, the following faults are possible:
  - Corrosion at connector
  - Specified torque (20 Nm) not achieved
  - Open circuit
  - Knock sensor defective
  - Loose ancillaries
  - Poor fuel quality

Display group 14, knock control

Notes:

• ◆ With this display group it is possible to check the ignition timing retardation for cylinders 1 and 2 at specific engine speeds and under specific load conditions.
• ◆ Causes for ignition timing retardation =>Display group 13

Display group 15, knock control

Notes:

• ◆ With this display group it is possible to check the ignition timing retardation for cylinders 3 and 4 at specific engine speeds and under specific load conditions
• ◆ Causes for ignition timing retardation =>Display group 13

Display group 16, knock control

Notes:

• ◆ If the difference between the highest and lowest knock control signals is more than 50%, this may be due to corrosion on the connector.
• ◆ If no faults are detected during the electrical testing of the knock sensor, the wiring and the plug connection, then the engine should be checked for loose ancillaries or engine damage =>Display group 13.
• ◆ At higher engine speeds, the voltage signal displayed for the knock sensors may reach values of up to 5.1 V.

Display group 17, distributor basic setting (engine code ADP only)

Notes:

The position of the Hall sender is set by rotating the distributor. The Motronic control unit can process the signal in a range from -12...+12 oCS.

Keep to a range of-3...+3 oCS when adjusting.

Display group 17, CAT heating (engine code ADR1) only)

1)With engine code AEB this display group is irrelevant, as the catalytic converter is located so close to the engine.

Notes:

• ◆ In order to bring the catalytic converter up to operating temperature as quickly as possible after a cold start, the engine speed is raised to approx. 1200 rpm during idling and the ignition timing is retarded up to a maximum of 6 oATDC. In the part throttle range only the retardation of the ignition angle is effective.
• ◆ This function for rapid heating of the catalytic converter is effective at starting temperatures of -10 to +39 oC.
  The function is aborted under the following conditions:
  - Engine speed greater than 4000 rpm
  - Load above 7.4 ms
  - Energy balance above 1.0
  - Full throttle for longer than 2 sec.
  - Vehicle speed greater than 55 km/h
  - A/C on
  As soon as the function has been aborted the display for the energy balance stops and is reset during the next start.
• ◆ The function does not become effective again if the values are below the above criteria.
• ◆ As soon as the energy balance counter reaches the value 1 the catalytic converter is at operating temperature (at least 120 ml of fuel have been burned). The counter keeps going up to a value of 2. This display has no relevance.

Display group 18, altitude compensation

Notes:

The Motronic control unit compares the load signal from the air mass meter with a load value calculated from the throttle valve angle and the engine speed. The difference between the two values is the altitude correction factor. On AEB engines the altitude compensation is carried out via the altitude sensor. Display zone 4 therefore always shows 0 %.

The following factors are influenced by the altitude compensation:

• ◆ Determination of starting fuel delivery
• ◆ Acceleration enrichment
• ◆ Lean mixture during deceleration
• ◆ Intake manifold pulsation compensation

No altitude compensation is necessary at altitudes of approx. 400 m above sea level under standard weather conditions.

- at sea level the correction factor is up to + 5 %.

- at an altitude of 2000 m the correction factor is approx. +20 %.

- the correction factor can vary significantly depending on the weather conditions.

Display group 19, torque reduction (vehicles with automatic gearbox only)

Notes:

• ◆ This display group can be used to assess how the ignition timing retardation reduces the engine torque on changing gear and thus makes gear shifts smoother.
• ◆ Because of the brief signal, the V.A.G 1551 does not always recognise the ignition timing retardation.

Display group 20, operating states

Note on Display zone 2:

On vehicles with a manual gearbox the display always reads "Gear ENG".

Note on Display zone 3:

On vehicles without air conditioner the display shows "A/C high" when the rear window heating is switched on.

Note on Display zone 4:

Vehicles without air conditioner always show "Compr. OFF".

Display group 21, operating status of lambda control

Notes:

At starting temperatures below +5 oC the lambda control is not released by the Motronic control unit until a coolant temperature of +5 oC is reached.

At starting temperatures above +5 oC the lambda control does not start until a signal voltage is detected.

When the lambda control is switched off, the engine runs according to the map stored in the control unit.

Display group 22

This Display group is only intended for development and production.

The values shown have no relevance for fault finding in the workshop.

Display group 23, adaptation of throttle valve control part

Note:

6 digits appear in Display zone 1

Note on Display zone 1:

If the specified readout value is not achieved: Perform basic setting of throttle valve control part

Note on Display zones 2, 3 and 4:

Display shows stop values learnt during last basic setting..

Note on Display zones 1, 2, 3 and 4:

If specified display value is still not attained after performing basic setting, check wiring for open circuit/short circuit and connectors for dirt/corrosion before renewing throttle valve control part.

Display group 24, knock control

Notes:

The knock control must retard the ignition timing as soon as knocking is detected in order to prevent damage to the engine.

However, the ignition timing retardation increases the exhaust gas temperature. There is a risk of overheating for the catalytic converter and on the AEB engine, also for the turbocharger.

An ignition timing retardation of for example 3 oCS on all cylinders has exactly the same effect as an ignition timing retardation of 12oCS on a single cylinder.

To avoid overheating, a richer mixture is supplied when the total ignition timing retardation exceeds approx. 10 oCS at full throttle

From a total ignition timing retardation of approx. 24 oCS the boost pressure is also reduced on the AEB engine.

Display group 25, boost pressure control (engine code AEB only)

Notes:

• ◆ This display group should only be assessed at full throttle.
• ◆ The driver sets the specified load through the position of the accelerator pedal (display zone 1).
  The specified load is reduced by the following correction factors:
  - Total ignition timing retardation through knock control above 24 oCS
  - Altitude compensation (map-dependent)
  - Coolant temperature above 105oC
  The boost pressure control limits the load to the specified load after correction.
• ◆ If the actual load deviates from the specified load by more than 0.5 ms (Display zone 2 or 3) then there is a fault in the boost pressure control.
• ◆ As soon as the Motronic control unit detects a difference of more than 1 ms, a fault is stored in the boost pressure control and the boost control solenoid valve is actuated with a fixed duty cycle of 5 %.

Display group 26, idling air demand (engine code AEB only)

Note on Display zone 1:

=>Display group 05, Display zone 3

Note on Display zone 2:

=>Display group 04, Display zone 2

Note on Display zone 3:

=>Display group 03, Display zone 3

Note on Display zone 4:

=>Display group 01, Display zone 1

Display group 27, load reduction through knock control (engine code AEB only)

Notes:

The boost pressure is reduced in order to limit the engine load.

The load is determined from the air mass meter signal.

If the sum of engine load plus load reduction reaches or exceeds a value of 8, this indicates a fault in the area of the air mass meter.

Display group 98, throttle valve control part

Note on Display zone 4:

ADP = Adaptation =>check throttle valve control part.