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.
2002 Toyota Corolla LE, StandardFACTORY OEM SERVICE PROCEDURE
Engine Control System Self-Diagnostics
- Introduction
- Self-Diagnostic System
- Scan Tool Problems
- Summary
- Diagnostic Trouble Code Definitions
- Diagnostic Tests
- Notes
- DTC P0100: Mass Airflow Meter Circuit
- DTC P0101: Mass Airflow Meter Circuit Range/Performance
- DTC P0110: Intake Air Temperature Sensor Circuit
- DTC P0115: Engine Coolant Temperature Sensor Circuit
- DTC P0116: Engine Coolant Temperature Sensor Circuit Range/Performance
- DTC P0120: Throttle Position Sensor Circuit
- DTC P0121: Throttle Position Sensor Circuit Range/Performance
- DTC P0125: Insufficient Coolant Temperature For Closed Loop Fuel Control
- DTC P0128: Thermostat Malfunction
- DTC P0130: Heated Oxygen Sensor No. 1 Circuit
- DTC P0133: Heated Oxygen Sensor No. 1 Circuit Slow Response
- DTC P0135: Heated Oxygen Sensor No. 1 Heater Circuit
- DTC P0136: Heated Oxygen Sensor No. 2 Circuit
- DTC P0141: Heated Oxygen Sensor No. 2 Heater Circuit
- DTC P0171 Or DTC P0172: System Too Lean/Rich
- DTC P0300: Random Misfire Detected
- DTC P0301: Cylinder No. 1 Misfire Detected, DTC P0302: Cylinder No. 2 Misfire Detected, DTC P0303: Cylinder No. 3 Misfire Detected &/Or DTC P0304: Cylinder No. 4 Misfire Detected
- DTC P0325: Knock Sensor Circuit
- DTC P0335 Or DTC P1335: Crankshaft Position Sensor Circuit
- DTC P0340: Camshaft Position Sensor Circuit
- DTC P0420: Catalyst System Efficiency Below Threshold
- DTC P0440: Evaporative Emission Control System Or DTC P0442: Evaporative Emission Control System Leak Detected
- DTC P0441: Incorrect EVAP Purge Flow Or DTC P0446: EVAP Vent Control Circuit
- DTC P0450: EVAP Pressure Sensor Circuit Or DTC P0451: EVAP Pressure Sensor Range/Performance
- DTC P0500: Vehicle Speed Sensor Circuit
- DTC P0505: Idle Air Control System Circuit
- DTC P1300: IGNITOR No. 1 Circuit
- DTC P1305: IGNITOR No. 2 Circuit
- DTC P1310: IGNITOR No. 3 Circuit
- DTC P1315: IGNITOR No. 4 Circuit
- DTC P1335: Crankshaft Position Sensor Circuit
- DTC P1346: Variable Valve Timing Circuit Range/Performance
- DTC P1349: Variable Valve Timing System Malfunction
- DTC P1520: Stoplight Switch Signal Circuit (A/T Only)
- DTC P1600: ECM Batt Circuit
- DTC P1656: Oil Control Valve Malfunction
- DTC P1780: Park/Neutral Position Switch Circuit (A/T Only)
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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