P0072-AMBIENT AIR TEMPERATURE SENSOR CIRCUIT LOW
P0072-AMBIENT AIR TEMPERATURE SENSOR CIRCUIT LOW
For a complete wiring diagram, refer to the Wiring Information.
Theory of Operation
The Ambient Air Temperature Sensor is a two wire sensor that is hard wired to the TIPM. The TIPM supplies a 5-Volt sensor signal and sensor ground to the Ambient Air Temperature Sensor. The sensor internal resistance changes in response to changes in ambient temperature. The TIPM provides the Powertrain Control Module (PCM) with ambient temperature over the CAN Bus network.
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When Monitored:
The ignition key on.
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Set Condition:
Ambient Temperature Sensor is less than the minimum acceptable value for 0.5 second. One Trip Fault. Three good trips to turn off the MIL.
Possible Causes |
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| (G31) AAT SIGNAL CIRCUIT SHORTED TO GROUND |
| (G31) AAT SIGNAL CIRCUIT SHORTED TO THE (G931) SENSOR GROUND CIRCUIT |
| AMBIENT AIR TEMPERATURE (AAT) SENSOR |
| TOTALLY INTEGRATED POWER MODULE (TIPM) |
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 28 - DTC-Based Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure).
| NOTE: | Diagnose any CAN C Bus Communication DTCs before continuing. |
| 1. | Turn the ignition one. |
| 2. | With the scan tool, select View DTCs. |
Is the DTC active?
Yes
- Go To 2
No
- Perform the INTERMITTENT DTC diagnostic procedure. (Refer to 28 - DTC-Based Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure).
| 1. | Turn the ignition off. |
| 2. | Disconnect the Ambient Air Temperature Sensor (AAT) harness connector. |
| 3. | Turn the ignition on, engine not running. |
| 4. | With a scan tool, select View DTCs. |
| NOTE: | The scan tool should display the P0073-AMBIENT AIR TEMPERATURE SENSOR CIRCUIT HIGH DTC with the connector disconnected. |
Does the scan tool display the DTC described above?
Yes
- Verify that there is good pin to terminal contact in the AAT Sensor and TIPM connectors. If ok, replace the Ambient Air Temperature Sensor.
- Perform the PCM VERIFICATION TEST. (Refer to 28 - DTC-Based Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure).
No
- Go To 3
3. CHECK THE (G31) AAT SIGNAL CIRCUIT FOR A SHORT TO GROUND
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| 1. | Turn the ignition off. |
| 2. | Disconnect the C4 TIPM harness connector. |
| 3. | Measure the resistance between ground and the (G31) AAT Signal circuit in the AAT Sensor harness connector. |
Is the resistance above 10k Ohms?
Yes
- Go To 4
No
- Repair the (G31) AAT Signal circuit for a short to ground.
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Perform the PCM VERIFICATION TEST. (Refer to 28 - DTC-Based Diagnostics/MODULE, Powertrain Control (PCM)
- Standard Procedure).
4. CHECK FOR THE (G31) AAT SIGNAL CIRCUIT SHORTED TO THE (G931) SENSOR GROUND CIRCUIT
 |
| 1. | Measure the resistance between the (G931) Sensor ground circuit and the (G31) AAT Signal circuit in the AAT Sensor harness connector. |
Is the resistance above 10k Ohms?
Yes
- Go To 5
No
- Repair the short between the (G931) Sensor ground circuit and the (G31) AAT Signal circuit.
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Perform the PCM VERIFICATION TEST. (Refer to 28 - DTC-Based Diagnostics/MODULE, Powertrain Control (PCM)
- Standard Procedure).
5. TOTALLY INTEGRATED POWER MODULE (TIPM)
| 1. | Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the AAT Sensor and the Totally Integrated Power Module (TIPM). |
| 2. | Look for any chafed, pierced, pinched or partially broken wires. |
| 3. | Look for broken, bent, pushed out or corroded terminals. Verify that there is good pin to terminal contact in the AAT Sensor and Totally Integrated Power Module connectors. |
| 4. | Perform any Technical Service Bulletins that may apply. |
Were there any problems found?
Yes
- Repair as necessary.
- Perform the BODY VERIFICATION TEST. (Refer to 28 - DTC-Based Diagnostics/MODULE, Totally Integrated Power (TIPM) - Standard Procedure).
No
- Replace and program the Totally Integrated Power Module (TIPM) in accordance with the service information.
- Perform the BODY VERIFICATION TEST. (Refer to 28 - DTC-Based Diagnostics/MODULE, Totally Integrated Power (TIPM) - Standard Procedure).