Diagnostic Aids
- If the ignition has been OFF for 8 hours or more, the IAT Sensor 1 parameter, the IAT Sensor 2 parameter and the ECT Sensor parameter should be within 15°C (27°F) of each other and also the ambient temperature. Turn ON the ignition, and immediately observe the parameters. Compare those sensor parameters to each other and also to the ambient temperature, to determine if the IAT Sensor 1 parameter is skewed.
- If the engine is cold, then at ignition ON, a properly functioning IAT sensor 1 will gradually increase the scan tool IAT Sensor 1 parameter. This is due to the heat that is generated by the MAF sensor heating elements.
- With the engine running, and depending on the ambient temperature, an IAT sensor 1 signal circuit that is shorted to the MAF sensor signal circuit can cause a rapid fluctuation in the IAT Sensor 1 parameter and can cause DTC P0111 to set.
IMPORTANT:
Determine the ambient temperature by using an accurate thermometer.
DTC P0111
| Step | Action | Values | Yes | No |
|---|---|---|---|---|
| Schematic Reference: Engine Controls Schematics Connector End View Reference: Powertrain Control Module Connector End Views or Engine Controls Connector End Views |
||||
| 1 | Did you perform the Diagnostic System Check - Vehicle? | - | Go to Step 2 | Go to Diagnostic System Check - Vehicle |
| 2 |
|
- | Go to Step 3 | Go to Testing for Intermittent Conditions and Poor Connections |
| 3 |
|
- | Go to Step 12 | Go to Step 4 |
| 4 |
|
- | Go to Step 12 | Go to Step 5 |
| 5 | Measure the resistance of the IAT sensor 1 signal circuit between the sensor and the PCM with a DMM. Refer to Circuit Testing
. Is the resistance within the specified range? |
0-10 Ω | Go to Step 6 | Go to Step 8 |
| 6 | Measure the resistance of the IAT sensor 1 low reference circuit between the sensor and the PCM with a DMM. Refer to Circuit Testing
. Is the resistance within the specified range? |
0-10 Ω | Go to Step 7 | Go to Step 9 |
| 7 |
|
- | Go to Step 11 | Go to Step 10 |
| 8 | Repair the high resistance in the IAT sensor 1 signal circuit. Refer to Wiring Repairs
. Did you complete the repair? |
- | Go to Step 12 | - |
| 9 | Repair the high resistance in the IAT sensor 1 low reference circuit. Refer to Wiring Repairs
. Did you complete the repair? |
- | Go to Step 12 | - |
| 10 | Replace the MAF/IAT sensor 1. Refer to Mass Airflow Sensor Replacement
. Did you complete the replacement? |
- | Go to Step 12 | - |
| 11 | Replace the PCM. Refer to Control Module References
for replacement, setup, and programming. Did you complete the replacement? |
- | Go to Step 12 | - |
| 12 |
|
- | Go to Step 2 | Go to Step 13 |
| 13 | Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed? |
- | Go to Diagnostic Trouble Code (DTC) List - Vehicle | System OK |