A vehicle comes into the shop and the technician retrieves the diagnostic code P0401 "EGR flow insufficient." Which of these could be the cause?
A) EGR valve stuck open
B) Electrical wiring shorted
C) Clogged EGR ports or passages
D) All of these are correct.

Question

Quizplus · Accepted Answer

All of these could be the cause of an insufficient EGR flow. The EGR valve could be stuck open, the electrical wiring could be shorted, and/or the EGR ports or passages could be clogged. Further diagnosis and testing would be necessary to determine the exact cause.

A Vehicle Comes into the Shop and the Technician Retrieves