EGR System Check
- With engine cool, ensure EGR valve is not loose or broken. If EGR valve is loose or broken, replace EGR valve. Start engine and warm to normal operating temperature.WARNING: Wear gloves if EGR valve is hot.
- Place finger on bottom of EGR valve diaphragm. Increase engine speed. Note if EGR valve diaphragm moves. If diaphragm does not move, allow engine to idle. Disconnect vacuum hose from EGR valve. See Fig 1 . Apply 8 in. Hg of vacuum to EGR valve and place finger on diaphragm. Vacuum should hold, diaphragm should move and engine may stall. If EGR valve operation is as specified, go to next step. If EGR valve operation is not as specified, replace EGR valve.
- Check for carbon in valve which may cause a restriction. Restriction may be small enough so that engine may stall, but large enough to cause DTC 51 to set. If EGR valve is okay, check EGR pressure transducer. If EGR valve is not okay, replace valve.