DAMAGE TO ECM/PCM CIRCUIT BOARD WHEN INSTALLING MEM-CAL

SUBJECT: DAMAGE TO ECM/PCM CIRCUIT BOARD WHEN INSTALLING A MEM-CAL (NEW MEM-CAL INSTALL PROCEDURE)

VEHICLES AFFECTED: ALL 1986-91 MODELS W/MEM-CAL

CONDITION:

--------- When installing a service replacement ECM/PCM, the use of, incorrect MEM-CAL installation procedures may cause the ECM/PCM to fail before it can be installed in the vehicle. This condition may appear as if the ECM/PCM were defective when it was shipped to the dealership, when in fact it was damaged while being installed. In addition this condition may also occur when installing an "updated" service MEM-CAL into the vehicles original equipment ECM/PCM.

CAUSE:

----- Excessive vertical force may be applied to the MEM-CAL resulting in flexing of the circuit board and damage to the connections between the circuit board and attached components. Excessive verticle force may be generated in two ways.

1. Incorrect MEM-CAL installation procedure.

2. Interference between MEM-CAL and cover.

CORRECTION: Use the following procedure.

Service Procedure:

Important: This procedure supersedes any instructions regarding MEM-CAL installation dated prior to September 1990.

1. Inspect the MEM-CAL to determine if a cork spacer is glued to the top side of the MEM-CAL assembly. If so, remove it prior to installation.

2. Align small notches with matching notches in the ECM/PCM MEM-CAL socket.

3. VERY GENTLY press down on the ends of the MEM-CAL until the locking levers are rotated toward the sides of the MEM-CAL.

Notice: To avoid ECM/PCM damage, do not press on the ends of the MEM-CAL until the levers snap into place.

Do not use any vertical force beyond the minimum required to engage the MEM-CAL into its socket.

4. While continuing light pressure on the ends of MEM-CAL, use your index fingers to press the locking levers inward until they are snapped into place. Listen for click.

5. Install MEM-CAL cover and install ECM/PCM in vehicle.

General Motors bulletins are intended for use by professional technicians, not a "do-it-yourselfer". They are written to inform those technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions and know-how to do a job properly and safely. If a condition is described, do not assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See a General Motors dealer servicing your brand of General Motors vehicle for information on whether your vehicle may benefit from the information.