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.
1995 Subaru Legacy BaseFACTORY OEM SERVICE PROCEDURE
Engine Controls - Tests W/Codes
- Introduction
- Self-Diagnostic System
- Summary
- Diagnostic Code Testing
- Notes
- DTC P0100 (QA) - Mass Air Flow (MAF) Sensor Circuit Malfunction
- DTC P0101 (QA_R) - Mass Air Flow (MAF) Sensor Circuit Range/Performance Problem
- DTC P0105 (P_S) - Pressure Sensor Circuit Malfunction
- DTC P0106 (P_R) - Pressure Sensor Circuit Range/Performance Problem
- DTC P0115 (TW) - Engine Coolant Temperature (ECT) Sensor Circuit Malfunction
- DTC P0120 (THV) - Throttle Position (TP) Sensor Circuit Malfunction
- DTC P0121 (Th_R) - Throttle Position (TP) Sensor Circuit Range/Performance Problem
- DTC P0125 (TW_Cl) - Insufficient Coolant Temperature For Closed Loop Fuel Control
- DTC P0130 (FO2_V) - Front Oxygen Sensor (O2S) Circuit Malfunction
- DTC P0133 (FO2_R) - Front Oxygen Sensor (O2S) Circuit Slow Response
- DTC P0135 (FO2H) - Front Oxygen Sensor (O2S) Heater Circuit Malfunction
- DTC P0136 (RO2_V) - Rear Oxygen Sensor (O2S) Circuit Malfunction
- DTC P0139 (RO2_R) - Rear Oxygen Sensor (O2S) Circuit Slow Response
- DTC P0141 (RO2_H) - Rear Oxygen Sensor (O2S) Heater Circuit Malfunction
- DTC P0170 (Fuel) - Fuel Trim Malfunction
- DTC P0201 (INJ1), DTC P0202 (INJ2), DTC P0203 (INJ3), DTC P0204 (INJ4) - Fuel Injection Circuit Malfunction
- DTC P0301 (Mis_1), P0302 (Mis_2),P0303 (Mis_3), P0304 (Mis_4) - Cylinder (1, 2, 3 Or 4) Misfire Detected
- DTC P0325 (Knock) - Knock Sensor Circuit Malfunction
- DTC P0335 (Crank) - Crankshaft Position (CKP) Sensor Circuit Malfunction
- DTC P0340 (Cam) - Camshaft Position (CMP) Sensor Circuit Malfunction
- DTC P0400 (EGR) - Exhaust Gas RECIRCULATION (EGR) Flow Malfunction
- Confirmation Of Actual Driving Pattern
- DTC P0403 (ERGSOL) - Exhaust Gas RECIRCULATION (EGR) Circuit Malfunction
- DTC P0420 (Cat) - Catalyst System Efficiency Below Threshold
- DTC P0441 (CPC_F) - Evaporative Emission Control System Incorrect Purge Flow
- DTC P0443 (CPC) - Evaporative Emission Control System Purge Control Valve Circuit Malfunction
- DTC P0500 (VSP) - Vehicle Speed Sensor Malfunction
- DTC P0505 (ISC) - Idle Control System Malfunction
- DTC P0506 (ISC_L) - Idle Control System Rpm Lower Than Expected
- DTC 507 (ISC_H) - Idle Control System Rpm Higher Than Expected
- DTC P0600 - Serial Communication Link Malfunction
- DTC P0601 (Ram) - Internal Control Module Memory Check Sum Error
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.