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P0405






P0405-EGR POSITION SENSOR CIRCUIT LOW





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

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 PCM. The EGR Valve motor contains three position sensors that detect to location of the EGR Valve. These sensors report the position of the valve back to the PCM over the EGR position signal wires. This diagnostic monitors the EGR solenoid driver circuits. If there is a short of open circuit detected for more than a calibrated period of time then the diagnostic will fail. The PCM lights the MIL lamp immediately after this diagnostic runs and fails. During this time the PCM will stop controlling the EGR valve. The default position for the valve is closed. The PCM will turn off the MIL lamp after the diagnostic runs and passes in four consecutive drive cycles.

- When Monitored:
Ignition on and battery voltage greater than 9 Volts.

- Set Condition:
All three EGR Valve position sensors are reading either High or Low for five seconds.





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.

NOTE: If there are any 5-Volt supply DTCs present, repair those DTCs before proceeding.

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 75 seconds.
5. Start the vehicle. It may be necessary to drive vehicle to reset DTC.
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. CHECK THE (F857) 5-VOLT SUPPLY FOR AN OPEN/HIGH RESISTANCE




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 (F857) 5-Volt Supply circuit at the EGR Valve harness connector.

Is the voltage reading 5.0 Volts?

Yes

- Go To 3

No

- Repair the (F857) 5-Volt Supply circuit.
- Perform the POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test.

3. CHECK THE EGR POSITION SIGNAL CIRCUITS FOR A SHORT TO VOLTAGE




1. Measure the voltage of the (K683) EGR Position Sensor Signal 1 circuit at the EGR Valve harness connector.
2. Measure the voltage of the (K685) EGR Position Sensor Signal 2 circuit at the EGR Valve harness connector.
3. Measure the voltage of the (K687) EGR Position Sensor Signal 3 circuit at the EGR Valve harness connector.

Is the voltage above 2.0 Volts?

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. CHECK THE (K916) SENSOR GROUND FOR AN OPEN/HIGH RESISTANCE
1. Turn the ignition off.
2. Disconnect the PCM C1 harness connector.
3. Measure the resistance of the (K916) Sensor Ground circuit between the EGR Valve harness connector and the PCM C1 harness connector.

Is the resistance below 5.0 Ohms?

Yes

- Go To 5

No

- Repair the (K916) Sensor Ground circuit for an open or high resistance.
- Perform the POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test.

5. CHECK THE EGR POSITION SIGNAL CIRCUITS FOR AN OPEN/HIGH RESISTANCE
1. Measure the resistance of the (K683) EGR Position Sensor Signal 1 circuit between the EGR Valve harness connector and the PCM harness connector.
2. Measure the resistance of the (K685) EGR Position Sensor Signal 2 circuit between the EGR Valve harness connector and the PCM harness connector.
3. Measure the resistance of the (K687) EGR Position Sensor Signal 3 circuit between the EGR Valve harness connector and the PCM harness connector.

Is the resistance less than 5.0 Ohms?

Yes

- Go To 6

No

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

6. CHECK THE EGR POSITION SIGNAL CIRCUITS FOR A SHORT TO GROUND




1. Measure the resistance between ground and the (K683) EGR Position Sensor Signal 1 circuit at the PCM harness connector.
2. Measure the resistance between ground and the (K685) EGR Position Sensor Signal 2 circuit at the PCM harness connector.
3. Measure the resistance between ground and the (K687) EGR Position Sensor Signal 3 circuit at the PCM harness connector.

Is the resistance less than 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 7

7. CHECK THE EGR VALVE
1. Reconnect the PCM C1 harness connector.
2. Replace the EGR Valve.
3. With the scan tool, erase DTCs.
4. Turn the ignition off for 75 seconds.
5. Start the vehicle. It may be necessary to drive vehicle to reset DTC.
6. With the scan tool, read DTCs.

Did the DTC reset?

Yes

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

No

- Repair complete.
- Perform the POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test.

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