Circuit/System Testing
- Ignition OFF, disconnect the harness connector at the IAT sensor.
- Ignition OFF, test for less than 5 ohm of resistance between the low reference circuit terminal E and ground.
- If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the engine control module (ECM).
- Ignition ON, verify the scan tool IAT parameter is less than -39°C (-38°F).
- If greater than the specified range, test the signal circuit terminal D for a short to ground. If the circuit tests normal, replace the ECM.
- Install a 3A fused jumper wire between the signal circuit terminal D and a good ground. Verify the scan tool IAT parameter is greater than 149°C (300°F).
- If less than the specified range, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the ECM.
- If all circuits test normal, test or replace the IAT sensor.