Engine Control Module: Service and Repair

REMOVAL
1. Turn the ignition key OFF.
2. Disconnect the negative battery cable.
3. Wait approximately 5 minutes.

Caution: Do not remove the clear plastic wire protector from the back of the Engine Control Module (ECM) connector. It is very difficult to reinstall without damaging the wires.

4. Remove the front console finishers.
5. Remove the bracket securing the harness to the car body.
6. Remove the screws securing the ECM to the car body.
7. Remove the bolt securing the electrical connector to the ECM.
8. Remove the ECM.

Warped Connectors:

INSTALLATION
***UPDATED BY TSB #NTB94-065 DATED MAY June 21, 1994
Reinstall in reverse order noting the following conditions.
Some models may fail to start if the ECM connector is not fully seated. The connector may be cocked to one side or misaligned with the center bolt tightened due to the plastic encasement on the ECM or the electrical connector itself being warped.

1. Line up the ECM connector with the wire harness connector and finger tighten the center attaching bolt. Make sure the connector is going in straight by pushing the connector at both ends.
2. When the bolt is finger tight and the harness connector seated evenly, use a 10mm open end/box wrench or 10mm socket/ratchet to start tightening the bolt. Count the 1/2 turns. Total 1/2 turns after finger tightening is 10 half turns.

Note: The 10 half turn method does not apply when installing bolt into a used ECM.

Note: The first point of resistance is the bolt threads starting to cut into the plastic just past the metal insert inside the ECM. You must continue turning the bolt to completely seat the bolt and connector.

3. Torque the bolt to approximately 4.9N-m or 0.5Kgm (45 in. lbs). When the connector is torqued and fully seated, the red pin on the harness connector will come out.

Fig. 3 Red Button:

A red plastic button will show when the connector is properly installed. Refer to Fig. 3.