Some 1999-2004 Ford F-Super Duty vehicles equipped with a 5.4L 2V engine may exhibit an intermittent rough idle. This may be due to non-commanded EGR flow.
EGR flow can be detected by comparing the stabilized DPFEGR KOER voltage at idle after manually opening and closing the EGR valve through eight cycles. Record the DPFEGR voltage after each cycle. If the DPFEGR voltage increases by 0.03V or more from the stabilized idle voltage and is associated with a rough idle, the valve should be replaced.
1. Connect NGS/WDS and monitor DPFEGR PID.
2. Record initial stabilized DPFEGR voltage.
3. Disconnect the EGR valve vacuum line and connect to a hand-held vacuum pump.
4. Raise RPM to prevent stalling and fully open the EGR valve.
5. Fully close the valve and return to idle.
6. Record stabilized DPFEGR voltage.
7. Repeat Steps 4-6, 8 (eight) times.
8. If voltage increases by 0.3V or more with an associated rough idle during any of the cycles, the EGR valve may be sticking. Lightly tap the EGR valve casting and observe if voltage returns to the initial DPFEGR value. If the DPFEGR voltage returns to the initial value and the rough idle condition is gone, replace the EGR valve. If there is no change, perform normal diagnostics.
The EGR valve is available as P/N XL3Z-9D475-CA.
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