Circuit/System Testing

Always perform the Diagnostic System Check - Vehicle .

1. Ignition OFF, disconnect the harness connector at the IAT sensor.
2. 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 control module.
3. Ignition ON, verify the scan tool IAT parameter is less than -36°C (-33°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 control module.
4. Install a 3A fused jumper wire between the signal circuit terminal D and the low reference circuit terminal E. Verify the scan tool IAT parameter is greater than 138°C (280°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 control module.
5. If all circuits test normal, test or replace the IAT sensor.