Diagnostic Trouble Codes - 1985
Buick
| 13 | Open Oxygen Sensor Circuit |
| 14 | Coolant Sensor Circuit (Signal Voltage Low) |
| 15 | Coolant Sensor Circuit (Signal Voltage High) |
| 21 | Throttle Position Sensor (Signal Voltage High) |
| 22 | Throttle Position Sensor (Signal Voltage Low) |
| 24 | VSS Buffer Not Attach to I.P.Clstr. '85 VIN 3(3.8L)MPFI |
| 32 | EGR Vacuum Control |
| 33 | Mass Air Flow Sensor (Signal Frequency High) |
| 34 | Mass Air Flow Sensor (Signal Frequency Low) |
| 42 | Electronic Spark Timing, 1985 VIN 3 (3.8L) MPFI |
| 42 | HEI-W/EST (VIN 3) |
| 43 | Electronic Spark Control (ESC) Circuit |
| 44 | Oxygen Sensor Circuit (Lean Exhaust Indicated) |
| 45 | Oxygen Sensor Circuit (Rich Exhaust Indicated) |
| 51 | PROM |
| 52 | CALPAK |
| 55 | ECM |
To extract a trouble code from the computer for diagnostic purposes, the Assembly Line Communication Link (ALDL) connector is used.
Ground terminals A and B with the ignition "ON" and engine not running. The system will enter the diagnostic mode. In this mode, the computer will display a Code 12, three consecutive times, by flashing the "CHECK ENGINE", "SERVICE ENGINE SOON" or "MALFUNCTION INDICATOR LAMP" or light. A Code 12 consists of one flash, a short pause, then two flashes in rapid succession.
After Code 12 is displayed, any stored trouble codes will be displayed by flashing the "CHECK ENGINE", "SERVICE ENGINE SOON" or "MALFUNCTION INDICATOR LAMP" light. All codes are displayed 3 times each then a code 12 will repeat. In the diagnostic mode, the computer will also energize all computer controlled relays and solenoids.
ALDL Connector (Located Underdash)
The ALDL diagnostic connector is located in the passenger compartment.