DTC Troubleshooting

Control System DTCs

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 How to Troubleshoot the Fuel And Emissions Systems.


1. Problem verification:

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

-2. Check the parameter(s) below with the HDS.





Do the current condition(s) match the threshold?
-YES- The failure is duplicated. Go to step 2.
-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 PCM.

2. Determine possible failure area (IAT sensor, others):

-1. Turn the ignition switch to LOCK (0).

-2. Disconnect the following connector.





-3. Turn the ignition switch to ON (II).

-4. Check the parameter(s) below with the HDS.





Do the current condition(s) match the threshold?
-YES- Go to step 3.
-NO- Replace the MAF sensor/IAT sensor Service and Repair, then do the repair verification.

3. Shorted wire check (TA line):

-1. Turn the ignition switch to LOCK (0).

-2. Jump the SCS line with the HDS.

-3. Disconnect the following connector.





-4. Check for continuity between test points 1 and 2.









Is there continuity?
-YES- Repair a short in the TA wire between the PCM (B42) and the MAF sensor/IAT sensor, then do the repair verification.
-NO- The TA wire is OK. Update the PCM PCM Update if it does not have the latest software, or substitute a known-good PCM Service and Repair, then do the repair verification.

Repair verification:

-1. Turn the ignition switch to LOCK (0).

-2. Reconnect all connectors.

-3. Turn the ignition switch to ON (II).

-4. Reset the PCM with the HDS How to Troubleshoot the Fuel And Emissions Systems.

-5. Do the PCM idle learn procedure PCM Idle Learn Procedure.

-6. Check for Pending or Confirmed DTCs with the HDS.


Is DTC P0112 indicated?
-YES- Check for poor connections or loose terminals at the MAF sensor/IAT sensor and the PCM. If the PCM was updated, substitute a known-good PCM Service and Repair, then recheck. If the PCM was substituted, go to step 1.
-NO- Troubleshooting is complete. If the PCM was substituted, replace the original PCM Service and Repair. If any other Pending or Confirmed DTCs are indicated, go to the indicated DTC's troubleshooting.