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.
1993 Toyota Corolla LEFACTORY OEM SERVICE PROCEDURE
Engine Controls - Tests W/Codes
- Introduction
- Summary
- Trouble Code Diagnostic Hints
- Trouble Code Identification
- Trouble Code Diagnostic Charts
- Notes
- Code 12 - Rpm Signal
- Code 13 - Rpm Signal
- Code 14 - Ignition Signal
- Code 16 - Electronically-Controlled A/T Signal (7A-FE)
- Code 21 - Oxygen Sensor Signal
- Code 22 - Coolant Temperature Sensor Signal
- Code 24 - Intake Air Temperature Sensor
- Code 25 Or 26 - Lean Or Rich Air/Fuel Mixture
- Code 27 - Sub-Oxygen Sensor Signal
- Code 31 - Map Sensor Signal
- Code 41 - Throttle Position Sensor (TPS) Signal
- Code 42 - Vehicle Speed Sensor Signal
- Code 43 - Starter Signal
- Code 51 - Switch Condition Signal
- Code 52 - Knock Sensor Signal (7A-FE)
- Code 71 - EGR System Malfunction
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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