ABS (4WAL) - Code 65 Misdiagnosis
89Chevy28Number: 90-64-5
Section: 5
Date: September 1989 965012 Corporate Bulletin No.:
Subject: FOUR WHEEL ANTI LOCK (4WAL) CODE 65 MISDIAGNOSIS
Model and Year: 1990 M VAN
TO: ALL CHEVROLET DEALERS
The instrument panel (I.P.) anti-lock warning light will only come on when an abnormal condition exists within the 4WAL system. It should be noted that if the I.P. anti-lock warning light is not on, it can accidentally be turned on and remain on by grounding diagnostic terminal "H" to "A" twice within ten seconds. If this occurs, and Code 65 is read out using the diagnostic procedure, then this code was probably set by the technician. This is a peculiarity within the 4WAL system, and should not be interpreted as a faulty condition. Technicians who have accidentally induced a Code 65 in this manner should simply clear the code prior to returning the vehicle to the customer.