SERVICE MANUAL UPDATE ELECT. ANTILOCK BRAKE SYSTEM

SUBJECT: ELECTRICAL SYSTEMS MANUAL UPDATE - ANTILOCK BRAKE SYSTEM (REVISED VALVE CONTROL TEST)

MODELS AFFECTED: 1991 PARK AVENUE/PARK AVENUE ULTRA

The 1991 Electrical Systems Manual, Antilock Brake System, Page 99, C: VALVE CONTROL TEST was printed with an incorrect terminal number.

The following updated illustration C: VALVE CONTROL TEST, should be used for correct diagnostic procedures:

C: VALVE CONTROL TEST ---------------------- o Electronic Brake Control Module (ECBM): disconnected o Ignition Switch: OFF o Main Relay: disconnected o Connect J 38716

[1] Less than 10 ohms between terminal 3 and suspect valve control terminal. If not, check wiring.

[2] Open circuit between suspect valve control terminal and ground. If not, check wiring.

o If all measurements are correct, replace ECBM, see (4)

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.