Engine Control Module: Service and Repair
Engine Control Module
Special tools, testers and auxiliary items required
• Hot air gun from the Wiring Harness Repair Kit (VAS 1978A))
• Nozzle attachment also from the Wiring Harness Repair Kit (VAS 1978A)
• Commercially available locking pliers (vise grips)
• Vehicle Diagnostic, Testing, and Information System (VAS 5051B)
The engine control module - 1 - is connected with a metal retainer - 2 and 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 engine control module (ECM) (for example to connect the test box or to replace the ECM), the protective housing must be removed.
The threads of the shear bolts have been coated with a locking compound, to further increase the difficulty of removing the shear bolts.
Removing
- If the engine control module is replaced, in guided fault finding select replace engine control module to (VAS 5051B).
- Turn the ignition and remove the ignition key.
- Pry off the caps on the wiper arms using a screwdriver.
- Loosen the nuts - arrows - by several turns.
- Loosen wiper arms from the wiper axle by tilting slightly.
- Then, remove nuts completely and remove wiper arms from the wiper axles.
• If wiper arm cannot be removed in this way, use a standard puller.
- Unclip the spray nozzles - arrow -.
- Push the spray nozzles, with water lines still attached, back through the opening and into the plenum chamber.
- Remove the rubber seal - 1 - from the plenum chamber cover - 2 -.
- Remove plenum chamber cover - 2 -.
The following steps are necessary through MY 2006
Move wiper arms to service position.
- To do this, close the hood.
- Turn the ignition on and then off again immediately. Within 10 seconds, press the windshield wiper lever downward once (mist wipe).
• The wiper arms now go into the service position.
- Then open the hood again.
All
- Remove ignition key.
Procedure:
To prevent damages (burning) of wire and harness connections, insulation and control modules, perform the following work procedures exactly! Observe operating instructions for heat gun.
- 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.
• Then, the shear bolts are heated with the heat gun. During this step, the holding effect that the locking compound has on the shear bolt threads is reduced, thereby allowing the shear bolts to be removed easier.
• Cover all painted components to prevent damage that may be caused by the heat gun or the locking pliers.
By heating the shear bolts, parts of the protective housing are heated intensely. Do not burn yourself on this! Make sure that only the shear bolts are heated as much as possible, and not any of the surrounding parts. Possibly cover these parts.
- Direct the heat gun nozzle at the shear bolt of the retaining tab.
- Switch on heat gun and heat bolt for approximately 20 to 25 seconds.
- Then grab the bolt head with the locking pliers and remove the shear bolt.
The procedure for the second shear bolt is exactly the same.
Then, the engine control module (ECM) can be separated from the protective housing.
Engine Control Module Bracket: Version 1
- Open clips - arrows - and remove the engine control module.
Engine Control Module Bracket: Version 2
- Unlock the front connector from the engine control module and disconnect it.
- Pull the engine control module (ECM) out from the retainer - arrow - (wiper arms in service position).
- Release and pull off the rear connector from ECM.
Installing Engine Control Module
Install in reverse order of removal.
- 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.
The following steps are necessary through MY 2006
- Move wiper arms to park position again.
- Close the hood to do this.
- Switch ignition on and press the windshield wiper lever downward once (mist wipe), the wiper arms will now move back to the park position,
- Activate the engine control module in the guided functions operating mode under replace engine control module on the (VAS 5051B).