SERVICE MANUAL UPDATE SEC. 6E3 REVISED PCM TROUBLE CODE 47

SUBJECT: SERVICE MANUAL UPDATE - SECTION 6E3 - REVISED PCM TROUBLE CODE 47

MODELS AFFECTED: 1992 RIVIERA

The 1992 Riviera Service Manuals do not include PCM Code 47. This bulletin provides diagnostics for PCM Code 47, BCM - PCM data circuit problem. When diagnosing a Code 47, refer to this bulletin and "Computer System Diagnosis" (SECTION 8D) in the service manual. This bulletin also revises the PCM diagnostic Codes table on Page 6E3-A-17.

CODE47

PCM-BCM DATA 3800 (VIN L) (TPI)

CHECK FOR MOMENTARY LOSS OF BCM POWER (CKT 640) OR GROUND (CKT 803), IGNITION "OFF" INPUT (CKT 343), IPC WAKE-UP (CKT 555) OR GROUND (CKT 803). REFERENCE "SELF-DIAGNOSTIC SYSTEM CHECK- CHARTS IN COMPUTER SYSTEM DIAGNOSIS (SECTION 8D). ALSO, ENSURE THAT MEM-CAL IS PROPERLY INSTALLED AND FULLY SEATED, ALDL COVER JUMPER PINS ARE INTACT, AND ALDL COVER IS PROPERLY INSTALLED.

IF CODE IS SET ALONG WITH ANY OF THE FOLLOWING HISTORY CODES: B332, B333, B334, B335, B336, B337, AND B552, SEE BCM TROUBLE CODE DIAGNOSIS (SECTION 8D2).

PCM DIAGNOSTIC CODES

CODE DESCRIPTION ILLUMINATE SES ---- ------------------------------------ -------------- 13 Oxygen Sensor - open circuit YES 14 Coolant Temperature Sensor - high temp. indicated YES 15 Coolant Temperature Sensor - low temp. indicated YES 16 System Voltage high or low YES 17 Spark Reference Circuit NO 21 Throttle Position Sensor voltage high YES 22 Throttle Position Sensor voltage low YES 23 Intake Air Temperature Sensor - low temp. indicated NO 24 Vehicle Speed Sensor Circuit YES 25 Intake Air Temperature Sensor - high temp. indicated NO 26 QDM Circuit YES 31 PRNDL Switch Circuit NO 34 MAF Sensor - low gm/sec indicated YES 36 Transaxle Shift Problem NO 38 Brake Input Circuit NO 41 Cam Sensor Circuit YES 42 Electronic Spark Timing (EST) Circuit YES 43 Electronic Spark Control (ESC) Circuit YES 44 Oxygen Sensor - lean exhaust indicated YES 45 Oxygen Sensor - rich exhaust indicated YES 47 PCM - BCM Data Circuit NO 51 MEM-CAL Error YES 58 PASS-Key Fuel Enable Circuit NO 61 Cruise Vent Solenoid Circuit NO 62 Cruise Vac Solenoid Circuit NO 65 Cruise Servo Position Circuit NO 67 Cruise Switches Circuit NO 68 Cruise System Problem (SPS Indicates high) NO

If a Code not listed above appears on Tech 1, ground ALDL diagnostic request CKT 451 and observe flashed codes. If Code does not reappear, Tech 1 data may be faulty. If Code does reappear, check for incorrect or faulty MEM-CAL.

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.