Idle Speed Stepper (ISS) Motor
- Set parking brake and block drive wheels. Route all tester cables away from cooling fans, drive belts, pulleys and exhaust system. Always allow engine speed to return to normal before disconnecting testing tools.
- With ignition off, disconnect ISS motor connector at throttle body. Connect Exerciser Tool (Part No. 8980 002 646) into ISS motor. See Fig 1 .
- Connect Red clip to battery positive cable. Connect Black clip to battery negative cable. Red light on exerciser tool will illuminate when properly connected. Start engine.NOTE: When switch on exerciser tool is in "High" or "Low" position, light on exerciser tool will flash indicating voltage pulses are being sent to ISS motor.
- Move exerciser tool switch to "High" position. Engine speed should increase. Move switch to "Low" position. Engine speed should decrease. If engine speed increases or decreases while using exerciser tool, ISS motor is functioning properly.
- Disconnect exerciser tool and reconnect ISS motor connector. If engine speed does not change, turn ignition off and remove ISS motor from throttle body.
- With ignition off, switch exerciser tool between "High" and "Low" positions. Check movement of ISS motor pintle. Pintle should move in and out. If pintle does not move, replace ISS motor.
- Start engine and test new ISS motor for proper operation. If pintle operates properly, check ISS motor bore in throttle body for blockage and clean as necessary. Reinstall ISS motor into throttle body.