P0403

P0403-EGR CONTROL CIRCUIT/OPEN





For a complete wiring diagram Consult Diagrams/Electrical

- When Monitored:
With the engine run time above 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.Initial Inspection and Diagnostic Overview

Diagnostic Test

1. DTC IS ACTIVE
Turn the ignition on.
With the scan tool, Clear DTCs in the Powertrain Control Module (PCM).
With the scan tool, actuate the EGR Valve Solenoid Duty Cycle.
With the scan tool, select View DTCs.
Is the DTC Active at this time?

Yes

- Go to 2

No

- Refer to the *CHECKING FOR AN INTERMITTENT DTC Diagnostic Procedure. Checking For An Intermittent DTC

2. (K35) EGR CONTROL CIRCUIT SHORTED TO VOLTAGE




Turn the ignition off.
Disconnect the EGR Valve Assembly connector.
Disconnect the C2 Powertrain Control Module (PCM) connector.
Turn the ignition on.
Measure the voltage of the (K35) EGR Control circuit in the EGR Valve Assembly harness connector.
Is there any voltage present?

Yes

- Repair the short to voltage in the (K35) EGR Control circuit.
- Perform the PCM Verification Test. Powertrain Verification Test

No

- Go to 3

3. (K35) EGR CONTROL CIRCUIT SHORTED TO GROUND




Turn the ignition off.
Measure the resistance between ground and the (K35) EGR Control circuit in the EGR Valve Assembly harness connector.
Is the resistance above 100 ohms?

Yes

- Go to 4

No

- Repair the short to ground in the (K35) EGR Control circuit.
- Perform the PCM Verification Test. Powertrain Verification Test

4. (K35) EGR CONTROL CIRCUIT OPEN OR HIGH RESISTANCE




CAUTION: 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 (K35) EGR Control circuit between the EGR Valve Assembly harness connector and the appropriate terminal of special tool #8815.
Is the resistance below 5.0 ohms?

Yes

- Go to 5

No

- Repair the open or high resistance in the (K35) EGR Control circuit.
- Perform the PCM Verification Test. Powertrain Verification Test

5. (Z902) GROUND CIRCUIT OPEN OR HIGH RESISTANCE




Using a 12 volt test light connected to 12 volts, check the (Z902) Ground circuit in the EGR Valve Assembly harness connector.

NOTE: The test light should be illuminated and bright. Compare the brightness to that of a direct connection to the battery.

Is the test light illuminated and bright?

Yes

- Go to 6

No

- Repair the open or high resistance in the (Z902) Ground circuit.
- Perform the PCM Verification Test. Powertrain Verification Test

6. EGR VALVE ASSEMBLY
Connect the C2 Powertrain Control Module (PCM) connector.
Turn the ignition on.
With the scan tool, actuate the EGR Valve Solenoid Duty Cycle.
Select the Duty Cycle reading of 79.9%
Using a 12 volt test light connected to ground, check the (K35) EGR Control circuit in the EGR Valve Assembly harness connector.

NOTE: 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.

NOTE: The voltage supplied to the solenoid circuit during the actuation may be less than battery voltage. The test light should be illuminated, but may not be as bright as a direct connection to the battery.

Is the test light illuminated during the actuation?

Yes

- Verify that there is good pin to terminal contact in the Solenoid and the Powertrain Control Module connectors. If OK, replace the EGR Valve Assembly.
- Perform the PCM Verification Test. Powertrain Verification Test

No

- Go to 7

7. POWERTRAIN CONTROL MODULE (PCM)
Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the EGR Valve Assembly and the Powertrain Control Module (PCM).
Look for any chafed, pierced, pinched, or partially broken wires.
Look for broken, bent, pushed out or corroded terminals.
Verify that there is good pin to terminal contact in the Solenoid and the Powertrain Control Module connectors.
Search for any Technical Service Bulletins that may apply.
Were any problems found?

Yes

- Repair as necessary.
- Perform the PCM Verification Test. Powertrain Verification Test

No

- Replace and program the Powertrain Control Module (PCM).
- Perform the PCM Verification Test. Powertrain Verification Test