Diagnostic Trouble Codes - 1986
Cadillac
| 12 | No Reference Pulse |
| 13 | Oxygen Sensor Circuit Not Ready |
| 14 | Coolant Sensor Circuit Shorted |
| 15 | Coolant Sensor Circuit Open |
| 16 | Generator Output Circuit |
| 18 | Open Crank Signal Circuit |
| 19 | Shorted Fuel Pump Circuit |
| 20 | Low Voltage In Fuel Pump Relays Circuit |
| 21 | Shorted Throttle Position Sensor Circuit |
| 22 | Open Throttle Position Sensor Circuit |
| 23 | EST Circuit Problem |
| 24 | Vehicle Speed Sensor (VSS) Circuit |
| 26 | Shorted Throttle Switch |
| 27 | Throttle Switch Circuit |
| 28 | Open Fourth Gear Circuit |
| 29 | Shorted Fourth Gear Circuit |
| 30 | Idle Speed Control Circuit |
| 31 | Shorted Manifold Absolute Pressure Sensor Circuit |
| 32 | Open Manifold Absolute Pressure Sensor Circuit |
| 33 | MAP or BARO Sensor Circuit |
| 34 | MAP Sensor Signal Too High |
| 35 | Shorted BARO Sensor Circuit |
| 36 | Open BARO Sensor Circuit |
| 37 | Shorted Manifold Air Temperature Sensor Circuit |
| 38 | Open Manifold Air Temperature Sensor Circuit |
| 39 | TCC Engagement Problem |
| 44 | Oxygen Sensor Circuit (Lean Exhaust Indicated) |
| 45 | Oxygen Sensor Circuit (Rich Exhaust Indicated) |
| 51 | PROM Problem |
| 52 | ECM Memory Reset Indicator |
| 53 | Distributor Signal Interrupt |
| 60 | Cruise Control - Transmission Not In Drive |
| 63 | Cruise Control - Vehicle & Set Speed Exceeded |
| 64 | Cruise Control - Vehicle Accel Exceeds Max Limit |
| 65 | Cruise Control - Coolant Temp Exceeds Max Limit |
| 66 | Cruise Control - Engine RPM Exceeds Limit |
| 67 | Cruise Control - Set & Resume Switch Circuit |
To extract a trouble 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 12, three consecutive times, by flashing the "CHECK ENGINE", "SERVICE ENGINE SOON" or "MALFUNCTION INDICATOR LAMP" or light. A 12 consists of one flash, a short pause, then two flashes in rapid succession.
After 12 is displayed, any stored trouble s will be displayed by flashing the "CHECK ENGINE", "SERVICE ENGINE SOON" or "MALFUNCTION INDICATOR LAMP" light. All s are displayed 3 times each then a 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.