SERVICE MANUAL UPDATE SEC. 6E3 (CODE 12 FLASHING EXPLANATION)

SUBJECT: SERVICE MANUAL UPDATE - SECTION 6E3 - DRIVEABILITY AND EMISSIONS EXPLANATION OF CODE 12 FLASHING

VEHICLES AFFECTED: 1990-1992 "A" 3300 (VIN N) ------------------------------------------------------------------------------

This bulletin is to make the service community aware of a system anomaly on "A" cars equipped with a 3300 (VIN N) engine.

When there are no trouble codes stored in the ECM's memory and the system is requested to flash out codes, Code 12 will flash three times then there will be a pause of approximately 30 seconds, then Code 12 will flash again.

It is suggested that a scan tool be used to check for trouble codes to avoid confusion. DO NOT replace ECM's or MEM-CALs to try to correct this anomaly, it is normal operation for this system.

If a trouble code is stored in memory, Code 12 will flash three times, then the trouble code(s) will flash three times, then back to Code 12, which is normal operation.

If trouble codes are cleared or the ECM is disconnected, and then flashing of codes is requested before the engine has been started, Code 12 will flash continuously.

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.