Idle Speed Stepper (ISS) Motor Test
- Set parking brake and block drive wheels. Route all tester cables away from cooling fans, drive belts, pulleys and exhaust system when connecting. Always allow engine speed to return to normal before disconnecting testing tools.
- With ignition off, disconnect ISS motor connector at throttle body. Install Idle Speed Stepper Motor Exerciser (Ele. CT01 ) into idle speed stepper 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 the "High" or "Low" positions, 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, as described 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. Leave exerciser connected to ISS motor.
- 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.