REAR WHEEL ANTI-LOCK CODE 9 MISDIAGNOSIS. GMC Truck S15 Pickup - 4WD 1988

For 1990-2009 cars

# REAR WHEEL ANTI-LOCK CODE 9 MISDIAGNOSIS

THE INSTRUMENT PANEL BRAKE WARNING LIGHT (I.P.) WILL ONLY COME ON WHEN AN ABNORMAL CONDITION EXISTS WITHIN THE RWAL SYSTEM. THE ECU MODULE WILL ONLY STORE ONE CONDITION (OR CODE) AT A TIME. THE VEHICLE SHOULD BE TEST DRIVEN AFTER THE INITIAL CONDITION HAS BEEN RESOLVED TO DETERMINE IF ANY OTHER CONDITIONS (CODES) EXIST.

IT SHOULD BE NOTED THAT IF THE I.P. BRAKE WARNING LIGHT IS NOT ON, IT CAN BE INDUCED TO COME ON BY GROUNDING DIAGNOSTIC TERMINAL "H" TO "A" FOR MORE THAN 20 SECONDS. WHEN THIS OCCURS, A CODE 9 WILL BE SET. THIS IS A PECULIARITY WITH THE RWAL SYSTEM, AND SHOULD NOT BE INTERPRETED AS A FAULTY CONDITION. TECHNICIANS WHO HAVE ACCIDENTALLY INDUCED A CODE 9 IN THIS MANNER SHOULD SIMPLY CLEAR THE CODE PRIOR TO RETURNING THE VEHICLE TO THE CUSTOMER.

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.

COPYRIGHT 1989 GMC TRUCK DIVISION, GENERAL MOTORS CORPORATION. ALL RIGHTS RESERVED.