Volkswagen Workshop Service and Repair Manuals

The engine control unit regulates the injection, throttle valve control part, Lambda control, ignition, knock control, activated charcoal filter solenoid valve 1, engine speed governor via injectors or fuel pump relay, intake manifold change-over as well as self-diagnosis.

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

• ◆ Fault reader V.A.G 1551 with cable V.A.G 1551/3

Work sequence

• ‒ First print out the control unit identification and thereby the previous control unit coding as follows:
• ‒ 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 .)

• ‒ Print out the control unit identification by pressing the fault reader print button.
• ‒ Press the ⇒key.
• ‒ Press keys 0 and 6 for the "End data transfer" function and confirm input with the Q key.

• ‒ Switch off ignition.
• ‒ Remove windscreen wiper arms and the cover for plenum chamber:

=> Repair group 92; Removing and installing windscreen washer system

• ‒ Release connector from control unit and pull off.

• ‒ → Press control unit to the right and pull out.
• ‒ Insert new control unit and press to the left.
• ‒ Check the previous coding and the coding of the new control unit => Page 24-106 .
• ‒ Match new control unit to throttle valve control part => Page 24-110
• ‒ Match new control unit to the electronic immobilizer => Page 24-115
• ‒ Then subsequently interrogate the fault memory of the new engine control unit and erase the fault memory if necessary.