Engine Control Module

Engine Control Module

Special tools, testers and auxiliary items required

• Puller (T10369)

• Heat Gun 220 V/50 Hz (VAS 1978/14A) with nozzle attachment from the Wiring Harness Repair Kit (VAS 1978 B)

• Small commercially available Locking Pliers

• Some engine control modules are not equipped with a protective housing. The removal and installation of the protective housing depends on the engine and transmission combination.

• The Engine Control Module (ECM) - 1 - is bolted to a protective housing - 5 -. To make removing the shear bolts - 4 - for the retaining tabs - 2 - more difficult, the threads are coated with locking compound.






• To disconnect the connectors from the ECM (for example to connect the test box or to replace the ECM), the protective housing must be removed.

Removing

- If the engine control module was replaced, select "Replacing engine control module (ECM)" in "Guided Fault-Finding". Use a vehicle diagnosis tester.

- Switch off ignition and remove ignition key.

- Remove the seal - 1 - and remove the plenum chamber cover - 2 -.






- Pry off the caps on the wiper arms with a screwdriver.






- Loosen nuts - arrows - a few turns.

- Mount the puller for removing wiper arms (T10369/1) onto the wiper arm - 1 - as illustrated.






- Mount the pressure piece - 2 - on the wiper axle.

- Turn the screw - 3 - clockwise until the wiper arm is pulled off the wiper axle.

- Remove the nuts and remove the wiper arms.


Danger of causing damage to the wind cowl.

• To prevent the cowl grille - 1 - from tearing when removing, coat transition between windshield and cowl grille with a soapy solution and pull grille up vertically out of fastening strip beginning at edge of window.








- Remove the screws - arrows - and remove the cowl panel trim from the windshield.

- Remove bolts - arrows - and remove cover for E-box at right in engine compartment.







Risk of burning on heater pump valve unit (at left in front of E box).

• Wear protective gloves when working near heater pump valve unit.

- Carefully pry off the retaining clip with a screwdriver - arrows 1 and 2 - and remove the ECM from the E-box.







Risk of damage (burning) from wiring and connectors, insulation and control modules.

• Follow the next steps exactly! Observe hot air gun operating instructions.

- Set the adjustment on the heat gun as shown in the illustration, with the temperature potentiometer - 2 - set to maximum heat and the two-stage airflow switch - 3 - set to level "3".






• Next, the thread of protective housing in which the shear bolts is threaded in is heated using the heat gun. This step decreases the locking effect of the locking compound on the thread of the shear bolts, thus allowing the shear bolts to be removed more easily.


There is a risk of burns.

• By heating the shear bolts, parts of the protective housing are heated intensely. Ensure as much as possible that only the shear bolt is heated and not the adjacent parts. Possibly cover these parts.

- Perform the following work steps in order on both shear bolts - 4 -.






- Guide nozzle of hot air gun on to shear bolt of protective housing.






- Switch the heat gun on and heat the bolt for approximately 20 to 25 seconds.

- Remove shear bolts with locking pliers - arrow -.






• The threads of both shear bolts - 3 -, that are screwed into the ECM, are not coated with a locking compound. The threads in the ECM housing must not be heated and do not require to be heated (unintentional heating of the ECM).






- Remove both shear bolts - 3 -.

- Separate the retaining tab - 2 - of the control module connector.

- Release and pull off connectors from ECM.

• When the connector is disconnected from the ECM, adaptation values are erased but the content of the DTC memory remains intact.

Installing

Installation is performed in the reverse order of removal, noting the following:

- After that, the engine control module (J623) must be equipped with the metal retainer.

- Clean threaded holes for shear bolts of locking compound residue. Cleaning can be performed with a thread cutter (tap).

- Use new shear bolts.

Perform the following step after installing a new ECM:

- Activate the engine control module in "Guided Functions" under "replace engine control module". Use a vehicle diagnosis tester for this.