Engine Control Module (ECM), Replacing

The Engine Control Module (ECM) is in the engine compartment on the left side near the vehicle battery mounting.

The ECM regulates the injection, throttle valve control module, oxygen control, ignition, knock control, EVAP purge regulator solenoid valve 1, the Leak Detection Pump, the engine speed governor via the injectors or fuel pump relay, the charge pressure control and On Board Diagnostic (OBD).

Special tools and equipment
- VAG 1551/1552 Scan Tool using VAG 1551/3 adapter cable

Work sequence
- Connect VAG 1551 (VAG 1552) Scan Tool.
- With ignition switched on but engine not running, press buttons -0- and -1- to select "Engine electronics" address word 01.

The VAG 1551 scan tool display will show the control module identification


021 906 259B MOTRONIC M5.9 AT V01 ->
Coding 0000 wsc xxxxx


- Press PRINT button on VAG 1551 and print out control module identification.
- Press -> button.
- Press buttons -0- and -6- to select "End output" and confirm input with -Q- button.

Display will appear as shown


Rapid data transfer HELP
Select function XX


- Switch ignition off..
- Remove cover for control module connector in upward direction.







- Disconnect control module connector -1- and connect to replacement control module -2-.
- Check previous coding and coding of new control module.
- Adapt new Engine Control Module (ECM) to immobilizer.
- Match new control module to throttle valve control module (basic setting).
- Check Diagnostic Trouble Code (DTC) memory of new engine control module and erase DTC memory if necessary.