Diagnostic Trouble Codes - 1991
Isuzu
| 13 | Open Oxygen Sensor Circuit |
| 14 | Coolant Temperature Sensor (High Temp Indicated) |
| 15 | Coolant Temperature Sensor (Low Temp Indicated) |
| 21 | Throttle Position Sensor (Signal Voltage High) |
| 22 | Throttle Position Sensor (Signal Voltage Low) |
| 23 | Manifold Air Temperature (MAT) Low Temp Indicated |
| 24 | Vehicle Speed Sensor (VSS) Circuit |
| 25 | Manifold Air Temperature (MAT) High Temp Indicated |
| 32 | EGR system fault |
| 33 | MAP sensor circuit (signal voltage high, low vacuum) |
| 34 | MAP sensor circuit (signal voltage low, high vacuum) |
| 42 | Electronic spark timing (EST) circuit |
| 44 | Oxygen Sensor Circuit (Lean Exhaust Indicated) |
| 45 | Oxygen Sensor Circuit (Rich Exhaust Indicated) |
| 51 | PROM error (faulty or incorrect MEM-CAL). |
To extract a trouble from the computer for diagnostic purposes, the Assembly Line Communication Link (ALDL) connector is used.
To activate the Diagnostic mode, a special connector located in the center console is utilized. When the ALDL (assembly line diagnostic link) connector is jumpered between terminals "A" and "C" with the ignition "ON" and the engine not running, the light will flash any stored codes.
The ALDL diagnostic connector is located in the passenger compartment.