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 Subaru Legacy LSi, FWDFACTORY OEM SERVICE PROCEDURE
Trouble Code Identification
TROUBLE CODE IDENTIFICATION
| Code | Circuit Affected | Probable Cause | ||
|---|---|---|---|---|
| 11 | Crank Angle Sensor | No Reference Signal | ||
| 12 | Starter Switch | Open/Short Circuit | ||
| 13 | Cam Angle Sensor | No Position Pulse | ||
| 14 | Fuel Injector No. 1 | Inoperative Fuel Injector | ||
| 15 | Fuel Injector No. 2 | Inoperative Fuel Injector | ||
| 16 | Fuel Injector No. 3 | Inoperative Fuel Injector | ||
| 17 | Fuel Injector No. 4 | Inoperative Fuel Injector | ||
| 21 | Coolant Temperature Sensor | Open/Short Circuit | ||
| 22 | Knock Sensor | Open/Short Circuit | ||
| 23 | Airflow Meter Circuit | Open/Short Circuit | ||
| 24 | Air Control Valve | Inoperative Air Control Valve | ||
| 31 | Throttle Position Sensor | Open/Short Circuit | ||
| 32 | Oxygen (O2) Sensor | Abnormal Sensor Signal | ||
| 33 | Vehicle Speed Sensor | No Reference Signal | ||
| 35 | Purge Control Solenoid Valve | Open/Short Circuit | ||
| 41 | Air/Fuel Ratio Control System | Faulty Learning Control Function | ||
| 42 | Idle Switch | Abnormal Reference Signal | ||
| 44 | Wastegate Duty Solenoid (Turbo) | Open/Short Circuit | ||
| 45 | Atmospheric Pressure Sensor (1) | Faulty Sensor | ||
| 45 | Pressure Sensor Duty Solenoid | Valve Inoperative | ||
| 49 | Airflow Sensor | Use of Improper Airflow Sensor | ||
| 51 | Neutral Safety Switch (M/T) | Open/Short Circuit | ||
| 51 | Inhibitor Switch (A/T) | Open/Short Circuit | ||
| 52 | Parking Brake Switch (A/T) | Open/Short Circuit | ||
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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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