Circuit/System Testing
IMPORTANT:
All electrical components and accessories must be turned OFF and allowed to power down.
- Ignition OFF, disconnect the harness connector at the MAF/IAT sensor.
- Ignition OFF and all vehicle systems OFF. It may take up to 2 minutes for all vehicle systems to power down. Test for less than 5 Ω 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 ECM.
- Ignition ON, verify the scan tool IAT Sensor parameter is colder than -39°C (-38°F).
- If warmer than the specified range, test the signal circuit terminal D for a short to ground. If the circuit tests normal, replace the ECM.
- Ignition ON, test for 4.8-5.2 V between the signal circuit terminal D and ground.
- If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the ECM.
- If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the ECM.
- Install a 3A fused jumper wire between the signal circuit terminal D and ground. Verify the scan tool IAT Sensor parameter is warmer than 149°C (300°F).
- If colder 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 MAF/IAT sensor.