DTC Troubleshooting

DTC Troubleshooting: P0112

DTC P0112: IAT Sensor Circuit Low Voltage

NOTE: Before you troubleshoot, record all freeze data and any on-board snapshot, and review the general troubleshooting information. Initial Inspection and Diagnostic Overview

1. Turn the ignition switch to ON (II).

2. Check the IAT SENSOR in the DATA LIST with the HDS.

Is about 356 °F (180 °C) or more, or 0.08 V or less indicated?
YES - Go to step 3.

NO - Intermittent failure, the system is OK at this time. Check for poor connections or loose terminals at the MAF sensor/IAT sensor and the ECM.


3. Turn the ignition switch to LOCK (0).

4. Disconnect the MAF sensor/IAT sensor 5P connector.

5. Turn the ignition switch to ON (II).

6. Check the IAT SENSOR in the DATA LIST with the HDS.

Is about 356 °F (180 °C) or more, or 0.08 V or less indicated?
YES - Go to step 7.

NO - Go to step 11.


7. Turn the ignition switch to LOCK (0).

8. Jump the SCS line with the HDS.

9. Disconnect ECM connector B (44P).

10. Check for continuity between MAF sensor/IAT sensor 5P connector terminal No. 5 and body ground.

Is there continuity?
YES - Repair short in the wire between the MAF sensor/IAT sensor and the ECM (B31), then go to step 13.

NO - Go to step 18.






11. Turn the ignition switch to LOCK (0).

12. Replace the MAF sensor/IAT sensor. Service and Repair

13. Reconnect all connectors.

14. Turn the ignition switch to ON (II).

15. Reset the ECM with the HDS.

16. Do the ECM idle learn procedure. ECM Idle Learn Procedure

17. Check for Temporary DTCs or DTCs with the HDS.

Is DTC P0112 indicated?
YES - Check for poor connections or loose terminals at the MAF sensor/IAT sensor and the ECM, then go to step 1.

NO - Troubleshooting is complete. If any other Temporary DTCs or DTCs are indicated, go to the indicated DTC's troubleshooting.


18. Reconnect all connectors.

19. Update the ECM if it does not have the latest software, ECM Update or substitute a known-good ECM. Initial Inspection and Diagnostic Overview

20. Check for Temporary DTCs or DTCs with the HDS.

Is DTC P0112 indicated?
YES - Check for poor connections or loose terminals at the MAF sensor/IAT sensor and the ECM. If the ECM was updated, substitute a known-good ECM, Initial Inspection and Diagnostic Overview then recheck. If the ECM was substituted, go to step 1.

NO - If the ECM was updated, troubleshooting is complete. If the ECM was substituted, replace the original ECM. Service and Repair If any other Temporary DTCs or DTCs are indicated, go to the indicated DTC's troubleshooting.