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.
1990 Toyota Corolla Base, AutomaticFACTORY OEM SERVICE PROCEDURE
Notes On Trouble Codes
- No other code will appear with code 11.
- When the malfunction in the system is repaired, the "CHECK ENGINE" light will go off but, the trouble code will remain in memory until the code is cleared.
- If trouble code 51 is still displayed after clearing the ECU memory, check if A/C switch is "OFF" and throttle valve is fully closed. Place gearshift lever in "P" or "N". Clear trouble code again. If code will not clear, recheck switches and circuit.
- If a malfunction occurs in test mode, the "CHECK ENGINE" light will remain on (all except code 51). ECU will erase all trouble codes when the ignition switch is turned off in test mode.
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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