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P0403






P0403-EGR CONTROL CIRCUIT/OPEN





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

Theory of Operation

The Exhaust Gas Recirculation (EGR) Valve is opened by a motor located on top of the EGR Valve. The EGR Valve is spring loaded closed. The motor electronically opens the valve and is controlled by the Engine Control Module (ECM). The EGR Valve motor contains three position sensors that detect the location of the EGR Valve. These sensors report the position of the valve back to the ECM over the EGR position signal wires. This diagnostic monitors the EGR solenoid driver circuits. If there is a shorted or open circuit detected for more than a calibrated period of time then the diagnostic will fail. The ECM lights the MIL lamp immediately after this diagnostic runs and fails. During this time the ECM will stop controlling the EGR valve. The default position for the valve is closed. The ECM will turn off the MIL lamp after the diagnostic runs and passes in four consecutive drive cycles.

- When Monitored:
Engine running.

- Set Condition:
Short or open circuit detected for more than calibrated amount of time.





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

1. ACTIVE DTC

NOTE: The EGR Valve harness connector is difficult to lock on to the valve. A connector not locked on completely will cause this DTC to set.

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.

NOTE: If DTC P0489 is present with this DTC, perform the P0489 diagnostic test procedure before continuing with this test. P0489

Did the DTC reset?

Yes

- Go To 2

No

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

2. (F855) 5-VOLT SUPPLY OPEN




1. Turn the ignition off.
2. Disconnect the EGR Valve harness connector.

NOTE: Check connectors - Clean/repair as necessary.

3. Turn the ignition on, engine not running.
4. Measure the voltage of the (F855) 5-volt Supply circuit at the EGR Valve harness connector.

Is the voltage reading 5.0 volts?

Yes

- Go To 3

No

- Repair the (F855) 5-volt Supply circuit.
- Perform the POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test.

3. EGR MOTOR CONTROL CIRCUITS SHORTED TO VOLTAGE




1. Measure the voltage on the (K682) EGR Motor Control 1 circuit at the EGR Valve harness connector.
2. Measure the voltage on the (K684) EGR Motor Control 2 circuit at the EGR Valve harness connector.
3. Measure the voltage on the (K686) EGR Motor Control 3 circuit at the EGR Valve harness connector.

Is there any voltage present?

Yes

- Repair the short to voltage in the appropriate circuit.
- Perform the POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test.

No

- Go To 4

4. EGR MOTOR CONTROL CIRCUITS OPEN




1. Turn the ignition off.
2. Disconnect the ECM C1 harness connector.

NOTE: Check connectors - Clean/repair as necessary.

3. Measure the resistance of the (K682) EGR Motor Control 1 circuit between the EGR Valve harness connector and the ECM C1 harness connector.
4. Measure the resistance of the (K684) EGR Motor Control 2 circuit between the EGR Valve harness connector and the ECM C1 harness connector.
5. Measure the resistance of the (K686) EGR Motor Control 3 circuit between the EGR Valve harness connector and the ECM C1 harness connector.

Is the resistance below 10.0 Ohms?

Yes

- Go To 5

No

- Repair the open or high resistance in the appropriate circuit.
- Perform the POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test.

5. EGR MOTOR CONTROL CIRCUITS SHORTED TO GROUND




1. Measure the resistance between ground and the (K682) EGR Motor Control 1 circuit at the ECM harness connector.
2. Measure the resistance between ground and the (K684) EGR Motor Control 2 circuit at the ECM harness connector.
3. Measure the resistance between ground and the (K686) EGR Motor Control 3 circuit at the ECM harness connector.

Is the resistance below 10k Ohms?

Yes

- Repair the short to ground in the appropriate circuit.
- Perform the POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test.

No

- Go To 6

6. EGR VALVE

NOTE: Perform the following resistance checks on the EGR Valve.

1. Measure the resistance between (K682) EGR Motor Control 1 and (K684) EGR Motor Control 2 circuits of the EGR valve.
2. Measure the resistance between (K682) EGR Motor Control 1 and (K686) EGR Motor Control 3 circuits of the EGR valve.
3. Measure the resistance between (K684) EGR Motor Control 2 and (K686) EGR Motor Control 3 circuits of the EGR valve.

Is the resistance between 1.8 and 2.4 Ohms?

Yes

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

No

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

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