Engine Control Module: Service and Repair

Engine Control Module

=> [ Without Anti-Theft Protection ]

=> [ With Anti-Theft Protection ]


This vehicle is equipped with two Engine Control Modules (ECMs) which cannot be visually distinguished from each other. If the ECMs are installed interchanged, the Diagnostic Trouble Code (DTC) memories are not detected. Therefore it is recommended to mark the ECMs, as well as their corresponding harness connectors, before removing in order to prevent interchanging the ECMs.

• The ECMs for the diesel direct fuel injection system are equipped with a DTC memory. Before and after repairs or adjustment work, The DTC memory must be checked. Refer to => [ Engine Control Module DTC Memory, Checking and Erasing ] Scan Tool Testing and Procedures.

- Before removing the ECM, the control module identification and with it also the coding of the previous control module must be checked. Refer to => [ Engine Control Module DTC Memory, Checking and Erasing ] Scan Tool Testing and Procedures.

Without Anti-Theft Protection

• If replacing one or more Engine Control Modules (ECMs), connect the vehicle diagnosis, testing and information system (VAS 5051B) and perform "Replace Engine Control Module" in Guided Functions.

- Turn off the ignition.

- Remove the right plenum chamber cover - D -.






- Release and disconnect the connector from the ECM - 1 - and/or - 2 -.






- Remove the old ECM and install the new ECM.

- Verify the old coding and code the new ECM. Refer to => [ Functions and Components, Adapting ] Programming and Relearning.

- Check the DTC memory of new the ECM and erase if necessary. Refer to => [ Engine Control Module DTC Memory, Checking and Erasing ] Scan Tool Testing and Procedures.

- Perform a test drive.

- Again, check the ECM DTC memory.

With Anti-Theft Protection

• If replacing one or more Engine Control Modules (ECMs), connect the vehicle diagnosis, testing and information system (VAS 5051B) and perform "Replace Engine Control Module" in Guided Functions.

Special tools, testers and auxiliary items required

• Hot Air Gun from Wiring Harness Repair Set (VAS 1978)

• Attachment Nozzle from Wiring Harness Repair Set (VAS 1978)

Removing

- Turn off the ignition.

- Remove the windshield wiper arms.

- Remove the plenum chamber cover. Refer to "Underbody Impact Guard".

• The threads of the shear bolts are equipped with locking compound. By heating the shear bolts using a hot air gun, inhibition effect of the locking compound is lowered.


Cover wires, harness connectors and control modules in the close vicinity of the ECM to prevent damage from burning.

Perform the adjustments on the hot air gun - 4 - as shown:

- Turn the potentiometer for temperature adjustment - 2 - to maximum heat output (600 °C (1112 °F)).






- Move the two stage switch for air quantity - 3 - to position 3.


By heating the shear bolts, parts of the protective housing are heated intensely. Wear protective gloves to prevent injuries.

- Guide the nozzle of the hot air gun onto the shear bolt - arrows -.

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

- Remove the shear bolt - arrows - by the bolt head using pliers.

The procedure for the second shear bolt is exactly the same.






- Remove the cover - 1 - from the control module.






- Slide the connector release catches - 1 - on the ECM outward and disconnect both harness connectors.






- Remove the ECM from the frame in the plenum chamber.

- Do the same to the second ECM.

Installing

- Install the ECM into the frame.

- Connect the harness connectors to the ECM and slide the release catches - 1 - inward.






- Place the cover - 1 - over the ECM and position the new shear bolts - arrows - by hand.

- Tighten new shear bolts uniformly until the bolt heads shear off.






- Install the plenum chamber cover. Refer to "Underbody Impact Guard".

- Install the windshield wiper arm.