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Encoding control unit > < Actuator diagnosis

A4 Mk1

Motronic fuel injection and ignition system (4-cyl.turbo) > 07.96
Self-diagnosis
Basic setting

With the engine stopped, the following operation can be performed with the basic setting:

  • ◆ Adaptation of the throttle valve control unit to the engine control unit => Display Group 98

With the engine running, the following operations can be performed with the basic setting:

  • ◆ Learning process for lambda control
    => each display group
  • ◆ Fault finding by selective actuation and deactuation of the lambda control => Display Group 99
  • ◆ Testing the ignition timing
    => Display Group 95

Test conditions for operations with engine running

  • ● Coolant temperature at least 80°C.
  • ● Electrical consumption units switched off (radiator fan must not run during the check)
  • ● Air conditioning system switched off
  • ● Gear selector lever in P or N position
  • ● No fault stored in fault memory
  • ‒ Connect the V.A.G 1551 fault reader (V.A.G 1552) and select the engine electronics control unit with the "Address word" 01. The ignition must be switched on during this procedure.
    (Connect the fault reader and select the control unit for the engine electronics ).
 
→ Indicated on display:
Rapid data transfer        HELP
Select function XX
  • ‒ Press keys 0 and 4 for function "Basic Setting" and confirm entry by pressing the Q key.
 
→ Indicated on display:
Basic setting    HELP
Enter display group number XX
  • ‒ Enter the desired display group number and confirm entry with the Q key.
 
→ Indicated on display (for example):
System in basic setting 98    ⇒
    1    2    3    4

Display group 08 on idling (warm engine, coolant temperature not less than +85°C)

To carry out the learning process of the lambda control, the solenoid valve for the active carbon canister is closed and the air conditioning compressor is switched off when a display group is selected.

System in basic setting 8

⇒

◂ Indicated on display

2.37 ms

0.4 %

0.1 %

λ-Adaptation

Tank venting
▪ λ-Adaptation: instantaneous mixture formation learning process (solenoid valve 1 for active carbon canister closed)
▪ Ten active: conditions for learning mixture formation not met (solenoid valve 1 for active carbon canister closed)

Learned value for mixture formation at part load (multiplicative)
▪ - 12...+ 12 %: OK
▪ Outside tolerance: Check lambda control => Page 24-39

Learned value for mixture formation at idling speed (additive)
▪ - 12...+ 12 %: OK.
▪ Outside tolerance: Check lambda control => Page 24-39

Injection period (per working stroke)
▪ 1.50...3.00 ms: OK
▪ < 1.50 ms: High proportion from tank breather system => Page 24-53
▪ > 3.00 ms: Engine loaded => Switch off consumption units

Display group 95 on idling (warm engine, coolant temperature not less than +85 °C)

With this display group, the idling stabilization is blocked and a fixed ignition angle of 12°before TDC is output.

System in basic setting 95

⇒

◂ Indicated on display

860 rpm

1.15 ms

12.0°before TDC

93.5 °C

Coolant temperature

Ignition timing
▪ Specified as fixed value by engine control unit

Engine load (injection period per crankshaft revolution)

Engine speed

Display group 98 with ignition on

The learning process (adaptation) of the throttle valve to the engine control unit is carried out and checked with this display group.

System in basic setting 98

⇒

◂ Indicated on display

4.420 V

3.880 V

Idling

ADP. OK

Adaptation status
▪ ADP. OK
▪ ADP. running. Adaptation is currently being carried out => wait
▪ ADP. ERROR Fault occurred during adaptation =>Check throttle valve control unit - Page 24-57

Operating status
▪ Idling: OK
▪ Other display: Idling switch open => check - Page 24-59

Voltage from throttle valve actuator -G127
▪ No specified result

Voltage from throttle valve potentiometer -G69
▪ No specified result

Display group 99 on idling (warm engine, coolant temperature not less than +85°C)

For fault finding, it is possible to jump between "basic setting" and "read measured values block" by pressing the keys 4 and 8. This switches the lambda control off and on.

System in basic setting 99

⇒

◂ Indicated on display

860 rpm

93.5°C

0.0 %

λ-Control off

Lambda control switched off

Control value for mixture formation (lambda control)

Coolant temperature

Engine speed

Read measured value block 99

⇒

◂ Indicated on display

860 rpm

93.5 °C

- 0.7 %

λ-Control on

Lambda control switched on

Control value for mixture formation (lambda control)

Coolant temperature

Engine speed

Encoding control unit > < Actuator diagnosis