Circuit/System Testing

DTC P0112

1. With the ignition ON, the engine OFF, and the MAF/IAT sensor harness disconnected, observe the IAT sensor parameter with a scan tool for a value of less than -39°C (-38°F).
   • If the IAT sensor parameter is less than -39°C (-38°F), replace the IAT sensor.
   • If the IAT sensor parameter is more than 148°C (298°F), test the IAT sensor signal circuit for a short to ground or a faulty ECM.

DTC P0113

1. With the ignition ON, the engine OFF, and the IAT sensor harness disconnected, measure for a voltage range of 4.8-5.2 volts between the IAT signal circuit and a ground.
   • If the voltage is more than 5.2 volts, test the IAT sensor signal circuit for a short to voltage or a faulty ECM.
   • If the voltage is less than 4.8 volts, test the IAT sensor signal circuit for an open, high resistance, or a faulty ECM.
2. Measure the voltage between the IAT low reference circuit and the IAT signal circuit.
   • If the voltage is less than 4.8 volts, test the IAT low reference circuit for an open, high resistance, or a faulty ECM.
3. With the ignition ON, the engine OFF, and the IAT sensor harness disconnected, observe the scan tool IAT temperature parameter for a value of less than -39°C (-38°F). Connect a 3-amp fused jumper wire between the signal circuit and low reference circuit. Observe the scan tool IAT temperature parameter for a value of more than 148°C (298°F).
   • If the temperature is more than 148°C (298°F), test the IAT signal circuit for a short to a 5-volt reference circuit.
4. If the IAT sensor circuits test normal, replace the IAT sensor.