Exhaust Gas Recirculation: Testing and Inspection

CHECKING THE EGR SYSTEM





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






1. EGR VALVE





NOTE: The engine temperature must be above 160°F for this test to be valid.

NOTE: Engine must be idling in park between 600 to 650 rpm.

1. With the scan tool, actuate the EGR Solenoid at 0%.
2. Select Data Display and read and note the MAF Per Cyl mg/hu reading.

NOTE: The EGR actuation will only occur for 30 seconds then actuation will stop automatically. Any readings or measurements must be taken within 30 seconds of beginning of actuation.

3. Repeat the above steps actuating the EGR Valve at 0%, 40%, 60%, and 100% noting the MAF readings during each actuation.
4. Refer to the chart and compare each of the EGR actuations and the expected MAF readings for each actuation.

Are the MAF Per Cyl mg/hu within the chart specifications for each percentage of EGR actuation?

Yes

- EGR system operating correctly. Test Complete.
- Perform the INTERMITTENT DTC diagnostic procedure. Checking for an Intermittent DTC.

No

- Go To 2

2. CHECK OPERATION OF EGR AIRFLOW CONTROL VALVE
1. Perform the CHECKING THE EGR AIRFLOW CONTROL VALVE procedure. Checking the EGR Airflow Control Valve.

Did the EGR Airflow Control Valve pass?

Yes

- Go To 3

No

- Repair as necessary.
- Perform the ECM VERIFICATION TEST. ECM Verification Test.

3. CHECK FOR INTAKE AND EXHAUST SYSTEM RESTRICTIONS
1. Turn the ignition off.
2. Inspect the exhaust system for damaged components that could cause exhaust flow blockage.
3. Inspect the EGR Valve and system for blockage or leaks, paying special attention to the EGR tube.
4. Inspect all air intake, crankcase vent, charge air cooler and turbocharger related hoses/tubes and connections for damage, air leaks or blockage.
5. Inspect the air filter for excessive dirt, soiling or other problems that may cause restricted air flow.

Were any problems found?

Yes

- Repair or replace as necessary.
- Perform the ECM VERIFICATION TEST. ECM Verification Test.

No

- Go To 4

4. FUSED ASD RELAY OUTPUT CIRCUIT OPEN
1. Turn the ignition off.
2. Disconnect the EGR Solenoid harness connector.
3. Turn the ignition on.
4. Using a 12-volt test light connected to ground, check the Fused ASD Relay Output circuit at the EGR Solenoid harness connector.

Is the test light on?

Yes

- Go To 5

No

- Repair the Fused ASD Relay Output circuit for an open.
- Perform the ECM VERIFICATION TEST. ECM Verification Test.

5. EGR SOLENOID GROUND CIRCUIT OPEN
1. Turn the ignition off.
2. Using a 12-volt test light connected to 12-volts, check the EGR Solenoid Ground circuit at the EGR Solenoid harness connector.

Does the test light illuminate brightly?

Yes

- Replace the EGR Solenoid/Valve.
- Perform the ECM VERIFICATION TEST. ECM Verification Test.

No

- Repair the EGR Solenoid Ground circuit for an open.
- Perform the ECM VERIFICATION TEST. ECM Verification Test.