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.
1992 Toyota Corolla LEFACTORY OEM SERVICE PROCEDURE
Engine Controls - Tests W/Codes
- Introduction
- Summary
- Trouble Code Identification Charts
- Code Charts
- Notes
- Ecu Terminal Identification
- Diagnostic Circuit Check
- Test No. 1 - Ecu Power Source
- Test No. 2 - Ecu (+B) Circuit
- Code 12, 13 - Rpm Signal
- Code 14/Test No. 3 - Rpm Signal
- Code 21/Test No. 4 - O2 Sensor Signal
- Code 22/Test No. 5 - Coolant Temperature Sensor Signal
- Code 24/Test No. 6 - Intake Air Temperature Sensor
- Code 25 - Lean Air/Fuel Mixture
- Code 26 - Rich Air/Fuel Mixture
- Code 31/Test No. 7 - Vacuum Sensor Signal
- Code 41/Test No. 8 - Throttle Position Sensor Signal
- Code 42 - Vehicle Speed Sensor Signal
- Code 43/Test No. 9 - Starter Signal
- Code 51/Test No. 10 - Switch Signal
- Code 71/Test No. 11 - EGR System Malfunction
- Test No. 12 - Injector Circuit
- Test No. 13 - Check Engine Circuit
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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