MALFUNCTION INDICATOR LAMP ON/ DIAG. TRBLE CODES 17,18 STORED

SUBJECT: MALFUNCTION INDICATOR LAMP ON/CODES 17 AND 18 STORED

MODELS AFFECTED: 1993 REGALS EQUIPPED WITH 3800 (VIN L) ENGINES

CONDITION:

Some 1993 Regals equipped with 3800 (VIN L) engines built prior to VIN P1415488 may set a Diagnostic Trouble Code (DTC) 17 and 18 and turn the Malfunction Indicator Lamp on. The car may also exhibit a rough running condition that clears up above 1200 RPM.

CAUSE:

When the PCM gets hot, around 160 degrees Fahrenheit, a transistor inside the PCM reacts slower than the software (PROM). This causes the diagnostic for DTC 17 and 18 to set.

CORRECTION:

If this condition exists, follow the diagnostic trouble code charts in the 1993 Regal Service Manual (pages 6E3-A-51 and 6E3-A-53) and repair as necessary. If the chart leads you to replace the PCM , it may be necessary to only replace the PROM.

To confirm that the PROM will correct this problem, the PCM needs to get warm. This should be accomplished by bringing the car inside the shop and letting the engine idle with the hood closed. It may take up to an hour for this problem to reoccur after the codes have been cleared. If the car has idled for an hour with the hood closed and a DTC 17 and/or 18 has not reappeared there is a problem with the PCM.

PARTS STATEMENT:

Parts are expected to be available on November 9, 1992. In case of limited inventory, parts will be placed on 400 control to waive VIP surcharges. Only verifiable emergency VIP orders will be accepted. SPO will make every effort to obtain parts. However, the part will be shipped premium transportation at dealer's expense and all other order types will be placed on backorder until the 400 control is removed.

PROM PROM PROM SERVICE SCANNER BROADCAST YEAR SERIES PART NUMBER I.D. NO. CODE ----- ------ ----------- -------- ---------

1993 Federal 16189642 9644 BDZW

1993 California 16189648 9654 BDZX

WARRANTY INFORMATION:

See applicable Labor Operation and Time.

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.