P0405

P0405 - EGR Position Sensor Circuit Low

For wiring diagrams, refer to.

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

• Set Condition: The PCM detects that the EGR valve assembly input voltage is less than the minimum acceptable value.

• Always perform the pre-diagnostic troubleshooting procedure before proceeding. Refer to => Non-DTC Based Diagnostics. Pre-Diagnostic Troubleshooting Procedure

Test Step 1 - DTC is Active

• Start the engine and allow it to reach normal operating temperature.

When the engine is operating, do not stand in direct line with the fan. Do not put your hands near the pulleys, belts, or fan. Do not wear loose clothing. Failure to follow these instructions can result in personal injury or death.

• Diagnose and repair any system voltage or sensor supply voltage DTCs before continuing with this test.

• With the scan tool, select view DTCs.

Is the status active for this DTC?

Yes

• Go to Test Step 2 => [ Test
Step 2 - 5 Volt Supply Circuit Voltage ]

No

• Refer to the checking for an intermittent DTC diagnostic procedure. Refer to => Non-DTC Based Diagnostics. Checking for an Intermittent DTC

Test Step 2 - 5 Volt Supply Circuit Voltage

• Turn the ignition OFF.

• Disconnect the EGR valve assembly connector.

• Turn the ignition ON.

• Measure the voltage of the 5 volt supply circuit in the EGR valve assembly harness connector.

Is the voltage more than 4.5 volts?

Yes

• Go to Test Step 6 => [ Test
Step 6 - EGR Signal Circuit Shorted to Ground ]

No

• Go to Test Step 3 => [ Test
Step 3 - 5 Volt Supply Circuit Shorted to Ground ]

Test Step 3 - 5 Volt Supply Circuit Shorted to Ground

• Turn the ignition ON.

• Disconnect the PCM connector.

• Measure the resistance between ground and the 5 volt supply circuit in the EGR valve assembly harness connector.

Is the resistance more than 100 ohms?

Yes

• Go to Test Step 4 => [ Test
Step 4 - 5 Volt Supply Circuit Shorted to Sensor Ground Circuit ]

No

• Repair the 5 volt supply circuit for a short to ground.

• Perform the PCM Verification Test. Refer to => Non-DTC
Based Diagnostics. PCM Verification Test

Test Step 4 - 5 Volt Supply Circuit Shorted to Sensor Ground Circuit

• Measure the resistance between the 5 volt supply circuit and the sensor ground circuit in the EGR valve assembly harness connector.

Is the resistance more than 100 ohms?

Yes

• Go to Test Step 5 => [ Test
Step 5 - 5 Volt Supply Circuit Open or High Resistance ]

No

• Repair the 5 volt supply circuit for a short to the sensor ground circuit.

• Perform the PCM Verification Test. Refer to => Non-DTC
Based Diagnostics. PCM Verification Test

Test Step 5 - 5 Volt Supply Circuit Open or High Resistance

• Turn the ignition OFF.

• Disconnect the PCM connector.

• Measure the resistance between ground and the EGR signal circuit in the EGR valve assembly harness connector.

Is the resistance more than 100 ohms?

Yes

• Go to Test Step 7 => [ Test
Step 7 - EGR Signal Circuit Shorted to Sensor Ground Circuit ]

No

• Repair the EGR signal circuit for a short to ground.

• Perform the PCM Verification Test. Refer to => Non-DTC
Based Diagnostics. PCM Verification Test

Test Step 7 - EGR Signal Circuit Shorted to Sensor Ground Circuit

• Measure the resistance between the EGR signal circuit and the sensor ground circuit in the EGR valve assembly harness connector.

Is the resistance more than 100 ohms?

Yes

• Go to Test Step 8 => [ Test
Step 8 - EGR Signal Circuit Open or High Resistance ]

No

• Repair the EGR signal circuit for a short to the sensor ground circuit.

• Perform the PCM Verification Test. Refer to => Non-DTC
Based Diagnostics. PCM Verification Test

Test Step 8 - EGR Signal Circuit Open or High Resistance

Do not probe the PCM harness connectors. Probing the PCM harness connectors will damage the PCM terminals, resulting in poor terminal to pin connection. Install Miller Special Tool #8815 to perform diagnosis.

• Measure the resistance of the EGR signal circuit between the EGR valve assembly harness connector and the appropriate terminal of special tool #8815.

Is the resistance less than 5.0 ohms?

Yes

• Go to Test Step 9 => [ Test
Step 9 - EGR Valve Assembly ]

No

• Repair the EGR signal circuit for an open or high resistance.

• Perform the PCM Verification Test. Refer to => Non-DTC
Based Diagnostics. PCM Verification Test

Test Step 9 - EGR Valve Assembly

• Turn the ignition OFF.

• Connect the PCM connector.

• Turn the ignition ON.

• With the scan tool, read the EGR valve assembly signal voltage.

• The sensor voltage should be approximately 5.0 volts (plus or minus.1 volt) with the connector disconnected.

Does the scan tool display the voltage as described more than?

Yes

• Replace the EGR valve assembly.

• Perform the PCM Verification Test. Refer to => Non-DTC
Based Diagnostics. PCM Verification Test

No

• Go to Test Step 10 => [ Test
Step 10 - PCM ]

Test Step 10 - PCM

• Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the EGR valve assembly and the PCM.

• Look for any chafed, pierced, pinched, or partially broken wires.

• Look for broken, bent, pushed out or corroded terminals.

• Monitor the scan tool data relative to this circuit and wiggle test the wiring and connectors.

• Look for the data to change or for the DTC to reset during the wiggle test.

• Refer to any technical service bulletins that may apply.

Were any problems found?

Yes

• Repair as necessary.

• Perform the PCM Verification Test. Refer to => Non-DTC
Based Diagnostics. PCM Verification Test

No

• Replace and program the PCM.

• Perform the PCM Verification Test. Refer to => Non-DTC
Based Diagnostics. PCM Verification Test