Engine Controls - ECM Installation Cautions

Classification: EF&EC94-011
Section: Engine Control System
Reference: TECHNICAL BULLETIN NTB94-065
Models: All Models
Date: June 21, 1994

ECM INSTALLATION

APPLIED MODELS:
All 1991 and later models

SERVICE INFORMATION

If a vehicle exhibits symptoms such as poor driveability, Check Engine light on, hard/no start condition, or no CONSULT interface, especially after a replacement ECCS control module (new ECM) has been installed, it is critical to ensure that the ECM connector and the center retaining bolt are fully seated.

This bulletin details the procedure for properly seating the harness connector when installing a replacement ECM.

CAUTION:

^ Before connecting or disconnecting the ECM harness, be sure to turn the ignition switch "OFF" and disconnect the battery negative cable.

^ Do not remove the clear plastic wire protector from the back of the ECM connector -- it's very difficult to reinstall without damaging the wires.

SERVICE PROCEDURE -- ECM HARNESS CONNECTOR INSTALLATION ONTO NEW REPLACEMENT ECM





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 occasionally pushing the connector at both ends. (See illustration.)

2. When the bolt is finger tight and the harness connector seated evenly, use a 10 mm open end/box wrench or 10 mm socket/ratchet to start tightening the bolt. Count the half turns. Total 1/2 turns after finger tightening is 10 half turns. (See illustration) The 10 half turn method does not apply when installing bolt into a used ECM -- finger tighten bolt, then torque as specified below.





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 45 in.lbs. (4.9 N-m or .5Kgm or 3.6 ft.lbs.). When the connector is torqued and fully seated, the orange pin on the harness connector will come out as shown above.

Caution:
Do not exceed 40-50 in.lbs. of torque on this bolt. If the head breaks off, the connector cannot be removed from the ECM.