HE76 - Check EGR Valve Function - Apply Vacuum With Hand Pump

- Key Off.

- Disconnect vacuum hose at EGR valve and plug hose.

- Connect a hand vacuum pump to to EGR valve.

- Start engine and bring to idle.

- Access DPFE and RPM PIDs with a Scan Tool.

- Slowly apply 5-10 inHg of vacuum to the EGR valve and hold it for 10 seconds. If engine wants to stall, increase rpm with throttle just enough to maintain idle rpm.

- Look for the following:

- EGR valve starts opening at about 1.6 inHg vacuum indicated by increasing DPFE PID voltage.
- DPFE PID voltage increasing until EGR valve is fully open. DPFE PID should read 2.5 volts minimum with full vacuum applied.
- DPFE PID voltage steady when vacuum is held. If voltage drops within a few seconds, the EGR valve or vacuum source could be leaking.

- Does the DPFE PID voltage indicate that the EGR valve is functioning as described in this test?

YES -- RECONNECT all components. GO to HE85. HE85 - Check EVR Vacuum Output By Grounding EVR Circuit

NO -- REMOVE and INSPECT the EGR valve for signs of contamination, unusual wear, carbon deposits, binding and other damage. SERVICE as necessary (use Rotunda EGR Valve Cleaner 021-00056, if needed). RECONNECT all components. Complete PCM reset to clear DTCs. Clearing Diagnostic Trouble Codes

Rerun quick test. Diagnostic Subroutines (DSR) - Extracting Codes