P0403
P0403 - EGR Control Circuit/Open
For wiring diagrams, refer to.
• When Monitored: With the engine run time more than a calibrated value, battery voltage greater than 10.4 volts, ECT within a specific range, and the EGR valve assembly control active.
• Set Condition: This PCM compares the circuit feedback to a calibrated closed range when the circuit is de-energized or to a calibrated open range when the circuit is energized. If the value is determined to be out of the calibrated range in either the de-energized or energized state for more than a calibrated amount of time, this DTC will set.
• 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
• Turn the ignition ON.
• With the scan tool, clear DTCs in the PCM.
• With the scan tool, actuate the EGR valve solenoid duty cycle.
• With the scan tool, select view DTCs.
Is the status active for this DTC?
Yes
• Go to Test Step 2 => [ Test
Step 2 - EGR Control Circuit Shorted to 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 - EGR Control Circuit Shorted to Voltage
• Turn the ignition OFF.
• Disconnect the EGR valve assembly connector.
• Disconnect the PCM connector.
• Turn the ignition ON.
• Measure the voltage of the EGR control circuit in the EGR valve assembly harness connector.
Is there any voltage present?
Yes
• Repair the EGR control circuit for a short to voltage.
• Perform the PCM Verification Test. Refer to => Non-DTC
Based Diagnostics. PCM Verification Test
No
• Go to Test Step 3 => [ Test
Step 3 - EGR Control Circuit Shorted to Ground ]
Test Step 3 - EGR Control Circuit Shorted to Ground
• Turn the ignition OFF.
• Measure the resistance between ground and the EGR control circuit in the EGR valve assembly harness connector.
Is the resistance more than 100 ohms?
Yes
• Go to Test Step 4 => [ Test
Step 4 - EGR Control Circuit Open or High Resistance ]
No
• Repair the EGR control circuit for a short to ground.
• Perform the PCM Verification Test. Refer to => Non-DTC
Based Diagnostics. PCM Verification Test
Test Step 4 - EGR Control 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 control 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 5 => [ Test
Step 5 - Ground Circuit Open or High Resistance ]
No
• Repair the EGR control circuit for an open or high resistance.
• Perform the PCM Verification Test. Refer to => Non-DTC
Based Diagnostics. PCM Verification Test
Test Step 5 - Ground Circuit Open or High Resistance
• Using a test lamp connected to 12 volts, check the ground circuit in the EGR valve assembly harness connector.
• The test lamp should be illuminated and bright. Compare the brightness to that of a direct connection to the battery.
Is the test lamp illuminated and bright?
Yes
• Go to Test Step 6 => [ Test
Step 6 - EGR Valve Assembly ]
No
• Repair the ground circuit for an open or high resistance.
• Perform the PCM Verification Test. Refer to => Non-DTC
Based Diagnostics. PCM Verification Test
Test Step 6 - EGR Valve Assembly
• Connect the PCM connector.
• Turn the ignition ON.
• With the scan tool, actuate the EGR valve solenoid duty cycle.
• Using a test lamp connected to ground, check the EGR control circuit in the EGR valve assembly harness connector.
• If the DTC is active, the actuation test may not be allowed by the PCM. If may be necessary to clear the DTCs before starting the actuation.
• The voltage supplied to the solenoid circuit during the actuation may be less than battery voltage. The test lamp should be illuminated, but may not be as bright as a direct connection to the battery.
Is the test lamp illuminated during the actuation?
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 7 => [ Test
Step 7 - PCM ]
Test Step 7 - 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.
• 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