EGR System Check
- With engine cool, remove EGR pressure transducer cap and filter. Check filter for contamination or damage. Use compressed air to clean filter, or replace filter if damaged. Install filter with coarser side facing outward and reinstall cap. See Fig 1
.
- Using a tee connector, connect a vacuum gauge between EGR valve and EGR pressure transducer. See Fig 2
. Start engine and check EGR valve seating by making sure that engine idles normally. If idle is okay, go to next step. If idle is rough and no other problems exist, replace EGR valve.
- Connect a jumper wire between duty check DLC terminals E1 and TE1 (located in engine compartment). With engine coolant temperature less than 117°F (47°C), accelerate engine to 2500 RPM and check vacuum gauge. If vacuum gauge indicates zero vacuum, go to next step. If vacuum is present, go to EGR SOLENOID VACUUM VALVE (EGR-SVV) check.
- Run engine until engine coolant temperature is greater than 127°F (53°C). Accelerate engine to 2500 RPM and check vacuum gauge. If vacuum gauge indicates low vacuum, go to next step. If vacuum gauge indicates zero vacuum or high vacuum, go to EGR SOLENOID VACUUM VALVE (EGR-SVV) check and EGR VACUUM PRESSURE TRANSDUCER check.
- Remove vacuum gauge. Using a hand-held vacuum pump, apply vacuum to EGR valve. Engine should run rough or stall. If engine runs and idles okay with vacuum applied, replace EGR valve. Ensure vacuum hoses are correctly installed. Remove jumper wire from duty check DLC.
Courtesy of GENERAL MOTORS CORP.
Courtesy of GENERAL MOTORS CORP.