Engine Control Module

Engine Control Module

Special tools, testers and auxiliary items required

• Heat Gun 220 V/50 Hz (VAS 1978/14) with Wiring Harness Repair kit (VAS 1978A)

• The engine control module (ECM) - 1 - is bolted to a protective housing - 5 -. To make removal of shear bolts - 4 - for 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 ECM was replaced, select the diagnostic object "Replacing engine control module (ECM)" in Guided Fault-Finding.

- Turn the ignition off and remove the ignition key.

- Pull off rubber seal of plenum chamber cover in direction of - arrow -.





- Remove plenum chamber cover - 1 - toward front.

- Pry off both covers - 3 - using a screwdriver.





- Loosen hex-nuts - 4 - by several turns.

- Loosen wiper arms - 2 - from the wiper axle by tilting slightly.

- Remove nuts completely and remove wiper arms.

• If wiper arm cannot be removed in this way, use a standard puller.

- Disconnect securing clips - 1 - and remove cowl grille - 5 -.

- Remove cover for E-Box in plenum chamber - arrows -.





- Using a screwdriver, carefully pry off mounting bracket - arrows - and remove ECM from E-Box.





• ECM remains connected at wiring harness.

CAUTION!
To avoid damage (burning) of wire connections and harness connectors, insulation and control modules, the following work steps must be adhered to 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 air flow switch - 3 - set to level " 3".





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

CAUTION!
By heating the shear bolts, parts of the protective housing will become extremely hot. Do not burn yourself on this! As far as possible, ensure only the shear bolts are heated and not any of the surrounding parts. Possibly cover these parts.

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





- Direct the heat gun nozzle at the protective housing shear bolts.





- 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 installed in 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.

• Adaptation values are erased when connectors are disconnected from the ECM, DTC memory content remains intact.

Installing

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

- The ECM must be equipped with the protective housing again.

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

- Use new shear bolts.

After installing a new ECM, the following work steps must be performed:

- Activate the ECM in Guided Fault-Finding under "Replacing engine control module (ECM)".