Engine Control Module, Slave

Engine Control Module, Slave

Engine management on the V10 is controlled by two engine control modules.

Both engine control modules communicate via private CAN-Bus.

Engine Control Module (ECM) (J623) (master) communicates which functions need to performed to Engine Control Module (ECM) 2 (J624) (slave).

• Both engine control modules are identical. If both engine control modules are removed, they must be marked before removal to prevent them from being interchanged when re-installing.

• Engine Control Module (ECM) (J623) (master): e.g. with an "M"

• Engine Control Module (ECM) 2 (J624) (slave): e.g. with an "S"





• Item - 3 - faces Engine Control Module (ECM) (J623) (master).

• Item - 1 - faces Engine Control Module (ECM) 2 (J624) (slave).

- If ECM was replaced, select diagnostic object "Replacing ECM" in "Guided Functions".

Special tools, testers and auxiliary items required

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

• Small, commercially available locking pliers - 3 - (vise grips)

• The 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 (e.g. to connect the test box or to replace the ECM), the protective housing must be removed.

Removing

- Turn ignition and remove the ignition key.

- Remove right cover from plenum chamber.

- Carefully pull cowl grill - 1 - as far as necessary out of retainer on windshield.

- Remove cover - 3 - over Engine Control Module (ECM) (J624).





- Remove Engine Control Module (ECM) 2 (J624) - 1 -. To do this, open retaining clip - 1 - and remove Engine Control Module (ECM) 2 (J624) from guide - 2 -.





To increase the difficulty with which the ECM connectors can be accessed, the ECM is secured in a metal housing with retaining tabs and shear bolts.

Remove Engine Control Module (ECM) 2 (J624).





The threads of the shear bolts - 4 - (that are not installed in ECM) are coated with a locking compound. For this reason, the threads must be heated with the heat gun to remove both bolts.





The threads of both shear bolts - 3 - (that are installed in 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).





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.





CAUTION!
By heating the threads, the retaining tabs, shear bolts and parts of the metal housing become very hot. Do not burn yourself on this! Make sure that only the threads are heated as much as possible, and not any of the surrounding parts. Possibly cover these parts.

Warm threads on connector side of shear bolts as shown in illustration.

Switch on heat gun and heat the bolt for approximately 20 to 30 seconds.





- Remove shear bolts with locking pliers (see direction of - arrow -).





- Both shear bolts that are screwed into the ECM do not require heating to be removed. They can be removed without heat.

- Disconnect metal retainers from connectors.

- Remove both retainer bolts from Engine Control Module (ECM) 2 (J624).

- Disengage connector from Engine Control Module (ECM) 2 (J624) and remove connector.

- Remove old Engine Control Module (ECM) 2 (J624) and connect new one.

Installing

Install in reverse order of removal.

- After that, the Engine Control Module (ECM) 2 (J624) 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).

- Always use new shear bolts.

- Carefully clip cowl grille back into retainer on windshield.

The procedures to follow after connecting the new ECM are described in Guided Fault-Finding and Guided Functions.