Circuit/System Testing
- Ignition OFF, disconnect the harness connector of the IAT sensor.
- Ignition ON, clear the DTC information with a scan tool.
- Ignition ON, verify that the IAT sensor parameter is at -40°C (-40°F).
- If greater than -40°C (-40°F), test the signal circuit of the IAT sensor for a short to ground. If the circuit/connections test normal, replace the ECM.
- Ignition OFF, test for less than 5 ohms of resistance between the low reference circuit and ground.
- If greater than 5 ohms, test the low reference circuit of the IAT sensor for an open/high resistance. If the circuit/connections test normal, replace the ECM.
- Ignition OFF, test for less than 5 ohms of resistance between the low reference circuit and ground.
- If greater than the specified value, test the low reference circuit for an open/high resistance. If the circuit/connections test normal, replace the ECM.
- Ignition ON, clear the DTC information with a scan tool.
- Connect a 1A fused jumper wire between the signal circuit and the low reference circuit. Verify the scan tool IAT sensor parameter is greater than 135°C (275°F).IMPORTANT: If the fuse in the jumper wire opens, the signal circuit is shorted to a voltage and the sensor may be damaged.
- If less than the specified value, test the signal circuit for an open/high resistance. If the circuit/connections test normal, replace the ECM.
- If all circuits/connections test normal, test or replace the IAT sensor.