'SERVICE ENGINE SOON' LIGHT CODE 32 (SERVICE PROCEDURE)

1988-89 M-VAN W/4.3L (VIN CODE Z) ENGINE

Some 1988 and 1989 M vans equipped with the 4.3L engine (VIN Code Z) may experience a Code 32 - EGR System malfunction. The customer may not experience a change in performance or driveability with a Code 32 set.

If normal diagnostics do not reveal the cause for Code 32, the following steps should be taken to correct the condition:

1. Check the TCC (Torque Converter Clutch) engagement solenoid/wiring harness for a short-circuit, and if the condition is found replace the harness.

2. If the TCC circuit is operating properly, replace the exhaust oxygen sensor (P/N 25105901). The sensor is currently available from GMSPO.

3. Confirm closed-loop operation of the engine. It is recommended that the following conditions be satisfied during confirmation to determine if the repairs made were effective. These conditions establish the requirements for running a Code 32test.

Road Load at normal operating temperature

Constant Throttle Position - TPS vokage - 1.3 V (minimum = 1.1 V, maximum = 1.5 V)

Vehicle Speed = 45 mph (minimum = 35 mph, maidmum = 55 mph)

Length of test drive - at least 2 to 3 miles

Use applicable labor operation and time per the

Labor Time Guide.

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.