Exhaust Gas Recirculation: Testing and Inspection

Removing EGR Vacuum Modulator Filter:

Installing Vacuum Gage:

Applying Vacuum to EGR Valve:

EXHAUST GAS RECIRCULATION SYSTEM CHECK
1. Remove EGR vacuum modulator cap and filter.
Inspect
^ Filter for contamination or damage.
Clean
^ Using compressed air, clean the filter.

2. Reinstall the filter and cap onto the EGR vacuum modulator.

IMPORTANT: Reinstall the filter with the coarser side facing outward.

3. Using a three-way connector, connect a vacuum gage to the hose between the EGR valve and the EGR vacuum modulator.
4. Check the seating of the EGR valve by starting the engine and making sure that it idles normally. If idle is rough and no other problems exist, replace EGR valve as necessary.
5. Connect a jumper between Data Link Connector (DLC) terminals "TE1" and "E1."
6. Make sure that the Engine Coolant Temperature (ECT) is below 47°C (117°F). Accelerate engine to 2,500 RPM and make sure that vacuum gage reads zero vacuum. If vacuum is present, refer to Exhaust Gas Recirculation Solenoid Vacuum Valve Check. Testing and Inspection
7. Run engine until ECT exceeds 53°C (127°F) and accelerate engine to 2,500 RPM and make sure that the vacuum gage reads low vacuum. If no, or high vacuum is indicated, refer to either:
Exhaust Gas Recirculation Solenoid Vacuum Valve Check Testing and Inspection

Exhaust Gas Recirculation Vacuum Modulator Check. Testing and Inspection

8. Remove vacuum gage and return vacuum hoses to their proper location.
9. Apply vacuum directly to EGR valve using a vacuum pump. The engine should run rough or even stall. If engine runs and idles fine with vacuum applied here, replace the EGR valve.
10. Reconnect vacuum hoses to their proper locations and remove jumper from DLC terminals.