volkswagen Workshop Repair Guides

Volkswagen Workshop Service and Repair Manuals

Checking additional signals > < Coding engine control unit
Motronic injection and ignition system (4-cyl. engine)
Engine control unit
Adapting engine control unit to throttle valve control part

Adapting teaches the engine control unit (with ignition switched on and engine not running) the throttle valve control part stop positions and a comparison graph between throttle valve potentiometer and throttle valve angle sender.

Adapting sequence must be performed if:

  • ◆ The throttle valve control unit is removed and installed
  • ◆ The throttle valve control unit is renewed
  • ◆ If when installing another engine another throttle valve control unit is installed

Special tools, workshop equipment, testers, measuring instruments and auxiliary items required

  • ◆ Fault reader V.A.G 1551 or vehicle system tester V.A.G 1552 with cable V.A.G 1551/3

Test conditions

  • ● No faults must be stored in fault memory
    , interrogating fault memory
  • ● The battery voltage must be at least 11.5 V.
  • ● All electrical consumers, e.g. lights and rear window heating must be switched off
  • ● The throttle valve must be at idling speed position.
  • ● The cruise control system must be functioning correctly if installed.

Work sequence

  • ‒ Connect the fault reader V.A.G 1551 (V.A.G 1552). Then switch ignition on and select engine control unit with the "Address word" 01.
    (Connecting fault reader and selecting engine control unit => Page 01-8 .)
 
→ Indicated on display:
Rapid data transfer     HELP
Select function XX
  • ‒ Press keys 0 and 4 for the function "Introduction of basic setting" and confirm entry with Q key.
 
→ Indicated on display:
Basic setting     HELP
Input display group number XXX
  • ‒ Press keys 0, 6 and 0 for the "Display group number 60" and confirm entry with Q key.
 
→ Indicated on display:
System in basic setting     60     ⇒
     xx -5     xx.x %     Idling ADP. runs

After pressing the Q-key the throttle valve positioner is driven to Min., Max. and some intermediate positions and the relevant throttle valve angles are stored in non-volatile memory. This procedure takes max. 10 seconds. The throttle valve then remains in the start position for a brief period then closes.

 
→ Indicated on display:
System in basic setting     60     ⇒
     xx -5     xx.x %     Idling ADP. OK

Adapting has been performed successfully.

To store the values:

  • ‒ Switch off ignition for at least 15 seconds (control unit run-on).

Note:

If the basic setting of the control unit is interrupted, the cause could be one of the following:

  • ◆ Throttle valve cannot reach the mechanical stop because of contamination e.g. oil deposits or an incorrectly adjusted throttle cable.
  • ◆ Battery voltage too low.
  • ◆ Throttle valve control unit or wiring is defective. Check => Page 24-40 .

After an interruption a fault is stored in fault memory.

  • ‒ End the engine basic setting by pressing the⇒ key.
  • ‒ Press keys 0 and 6 for the function "End output" and confirm entry with the Q key.

Checking additional signals > < Coding engine control unit