Engine Controls - Additional Diagnostics Code 32, EGR
89chevy11GMC NUMBER: 89-T-79
GROUP: 6E - Engine Emission
DATE: July, 1989
CORPORATE
NUMBER: 936512
SUBJECT: "SERVICE ENGINE SOON" LIGHT - CODE 32 STORED (SERVICE PROCEDURE)
MODELS: 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 driveabihty 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 32 test.
^ Road Load at normal operating temperature
^ Constant Throttle Position - TPS voltage = 1.3 V (minimum- = 1.1 V, maximum = 1.5 V)
^ Vehicle Speed = 45 mph (minimum = 35 mph, maximum = 55 mph)
^ Length of test drive - at least 2 to 3 miles
Use applicable labor operation and time per the Labor Time Guide.