P040D

P040D-EXHAUST GAS RECIRCULATION TEMPERATURE SENSOR 1 CIRCUIT HIGH





For a complete wiring diagram Refer to Diagrams/Electrical.

Theory of Operation


The exhaust gas recirculation temperature sensor is a variable resistor sensor and is used to measure the temperature of the EGR gas flow after it exits the EGR cooler. The ECM supplies 5-volts to the exhaust gas recirculation temperature signal circuit. The ECM monitors the change in voltage caused by changes in the resistance of the sensor to determine the coolant temperature. The exhaust gas recirculation temperature value is used by the ECM for the engine protection system, and engine emissions control. This fault code is set active if the sensor signal voltage is above or below the normal operating range for the sensor and the ECM has commanded the EGR valve open. This fault code will not be set active if the ECM has commanded the EGR valve closed. If this fault becomes active the ECM will light the MIL light immediately. During this time the EGR valve will be closed. The ECM turns off the MIL when the diagnostic runs and passes in 4 consecutive drive cycles.

- When Monitored:
When the key is on and battery voltage is above 10.4 volts.

- Set Condition:
The circuit voltage to the ECM is above a calibration threshold for a calibratable period of time.







Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. Initial Inspection and Diagnostic Overview


Diagnostic Test


1. P040D ACTIVE
With the scan tool, read DTC's.
Is DTC P040D Active?

Yes


- Go To 2


No


- Refer to the INTERMITTENT CONDITION - DIESEL Symptom. Intermittent Condition



2. (K935) OPEN SIGNAL CIRCUIT




Disconnect the ECM harness connector.

NOTE: Check connectors - Clean/repair as necessary.

Measure the resistance between the engine harness ECM connector and the engine harness EGR temperature sensor connector of the (K935) Signal circuit.
Is the measured resistance less than 10 ohms?

Yes


- Go to 3


No


- Repair the open (K935) Signal circuit.
- Perform POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test



3. (K914) OPEN RETURN CIRCUIT




Measure the resistance between the engine harness ECM connector and the engine harness EGR temperature sensor connector of the (K914) Return circuit.
Is the measured resistance less than 10 ohms?

Yes


- Go to 4


No


- Repair the open (K914) Return circuit.
- Perform POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test



4. EXHAUST GAS RECIRCULATION TEMPERATURE SENSOR




Turn the ignition off.
Disconnect the exhaust gas recirculation temperature sensor harness connector.

NOTE: Check connectors - Clean/repair as necessary.

Measure the resistance between the EGR temperature SIGNAL circuit and the EGR temperature RETURN circuit of the EGR temperature sensor.
Is the measured resistance between 200 ohms and 2.4M ohms?

Yes


- Go to 2


No


- Replace the EGR temperature sensor.
- Perform POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test



5. ECM
Reconnect the ECM harness connectors.
Turn the ignition on.
With the scan tool, erase DTC's.
While monitoring with the scan tool, use a jumper wire and connect the sensor signal circuit to the sensor return circuit at the sensor connector.
Did the DTC P040C set?

Yes


- Test complete.


No


- Replace the ECM.
- Perform POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test