Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
1991 Nissan-Datsun Sentra SE-RFACTORY OEM SERVICE PROCEDURE
Trouble Code Definition
TROUBLE CODE IDENTIFICATION CHART
| Code (1) | System/Circuit Affected | Probable Cause | ||
|---|---|---|---|---|
| 11 | Crank Angle Sensor | Loss Of Signal | ||
| 12 | Mass Airflow Sensor | MAF Signal High Or Low | ||
| 13 | Coolant Temp. Sensor | Open/Shorted Circuit | ||
| 14 | Vehicle Speed Sensor (VSS) | No VSS Signal | ||
| 21 | No Ignition Reference Pulse | Loss Of Primary Signal | ||
| 31 | ECU | Signals Out Of Range | ||
| 32 | EGR Sensor (Calif.) | No EGR Action | ||
| 33 | O2 Sensor (Left Side) | Open Circuit Or High O2 Signal | ||
| 34 | Knock Sensor | Open/Shorted Circuit | ||
| 35 | EGR Temp. Sensor (Calif.) | Open/Shorted Circuit | ||
| 43 | Throttle Sensor | Open/Shorted Circuit | ||
| 45 | Injector Leak (Calif.) | Leak At Injector | ||
| 55 | No Malfunction Recorded are available on all models. | No Faults Detected | ||
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Factory Service Tools
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.
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