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.
1991 Toyota Camry Base, AutomaticFACTORY OEM SERVICE PROCEDURE
Idle Speed Control System: 2.0L
- Warm engine to normal operating temperature. Ensure idle speed is correct. Apply parking brake, block drive wheels and place transaxle in Neutral.
- Install jumper wire between terminals "TE1" (or "T") and "E1" of check connector located near left shock tower. See Fig 1. Engine RPM should increase to 1000-1300 RPM for 5 seconds and then return to idle.
- If engine RPM was not within specification, check Idle Speed Control (ISC) valve, wiring to ECU, and ECU grounds. If engine RPM was within specification, remove jumper wire. Turn ignition off.
- Unplug ISC valve connector on bottom of throttle body. Using ohmmeter, measure resistance between terminals "B+" and "ISC1", and between "ISC2" and "B+". See Fig 2. Replace valve if resistance is not within 16-17 ohms.
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.