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.
Idle Speed Actuator (ISA) Motor
ISA motor acts as movable idle stop to change throttle stop angle. Both engine idle speed and deceleration throttle stop are set by ISA. ECU sends varying voltage outputs to control ISA motor, depending upon engine operating condition.
Throttle stop angle is determined by inputs from A/C system (on/off or clutch engaged), A/T selector position switch, power steering pressure switch, and closed throttle switch. Under normal engine operating conditions, engine idle is maintained at pre-programmed RPM which may vary slightly due to engine operating conditions. No idle speed adjustment is provided.
For cold engine starting, throttle is held open for longer period to provide adequate engine warm-up prior to normal operation. When starting hot engine, throttle open time is shorter. Under deceleration conditions, throttle is held slightly open.
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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.