P007C

P007C-CHARGE AIR COOLER TEMPERATURE SENSOR CIRCUIT LOW




For a complete wiring diagram, refer to the Wiring Information Electrical Diagrams.
Theory of Operation

The Air Cooler Temperature Sensor (CAC) and the Boost Pressure Sensor are combined in one sensor and are located near the EGR Airflow Throttle Control Valve. The Engine Control Module (ECM) provides a 5-volt reference voltage to the sensor. The ECM monitors the temperature of the air entering the intake using the CAC. At key on after an 8 hour cold soak, the CAC Temperature Sensor is compared to the Battery Temperature Sensor, Intake Temperature Sensor, and Coolant Temperature Sensor readings. If the temperatures differ more than a calibrated amount, a DTC is recorded. In the case that all four sensor values are distributed over a range of temperatures this diagnostic will not run. A block heater is one possible cause of such a condition. The key on monitor is disabled for ambient temperatures below 20°F. The rationality check looks at the temperature reading from the CAC Temperature Sensor over time and ensures that it changes. This monitor is used to verify the sensor is responding with temperature change. Both the key-on and rationality error require that the diagnostic fails in two consecutive drive cycles before the MIL lamp is lit. The ECM turns off the MIL lamp when the diagnostic runs and passes in 4 consecutive drive cycles.

- When Monitored:
With ignition on and battery voltage greater than 10.4 volts.

- Set Condition:
The CAC signal voltage is below 0.25 of a volt for five seconds.





Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. Pre-Diagnostic Troubleshooting Procedure.

1. ACTIVE DTC

NOTE: If there are any 5-volt supply DTCs present, repair those DTCs before proceeding with this test.

1. Turn the ignition on.
2. With the scan tool, record all Freeze frame data.
3. With the scan tool, erase DTCs.
4. Turn the ignition off for 30 seconds.
5. Turn the ignition on.
6. With the scan tool, read DTCs.

Did the DTC reset?

Yes

- Go To 2

No

- Perform the INTERMITTENT CONDITION diagnostic procedure.Intermittent Condition Test.

2. (K21) CAC TEMPERATURE SENSOR SIGNAL CIRCUIT SHORTED TO GROUND




1. Turn the ignition off.
2. Disconnect the CAC Temperature Sensor harness connector.
3. Disconnect the ECM C1 harness connector.

NOTE: Check connectors - Clean/repair as necessary.

4. Measure the resistance between ground and the (K735) CAC Temperature Sensor signal circuit at the CAC Temperature Sensor harness connector.

Is the resistance below 10k Ohms?

Yes

- Repair the short to ground in the (K735) CAC Temperature Sensor signal circuit.
- Perform the POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test.

No

- Go To 3

3. ENGINE CONTROL MODULE (ECM)
1. Reconnect the ECM C1 harness connector.
2. Reconnect the CAC Temperature Sensor harness connector.
3. Turn the ignition on.
4. With the scan tool, erase DTCs.
5. While monitoring with scan tool, disconnect the CAC Temperature Sensor harness connector.

Did the DTC P007D set?

Yes

- Replace the CAC/Boost Pressure Sensor.
- Perform the POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test.

No

- Replace the Engine Control Module (ECM).
- Perform the POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test.