Questions and Answers

Ford Crown Victoria DPFE Q. I own a 1995 Ford Crown Victoria. It is a police interceptor model. It has been very dependable for me for the past 2½ years. I have only recently been experiencing a problem with the check engine light coming on. When the code is read, it indicates EGR valve excess flow. I replaced the EGR valve and the code reappeared.

I had the codes reset and usually within 20 minutes the light returns.

I am in the military and currently stationed in Germany. Getting parts for a U.S. car is very difficult and can take a while through the mail system. I was wondering if I might have a problem with the DPFE sensor? I have not noticed any problems with performance, however fuel consumption seems to have increased. I've told my wife it is probably due to the driving conditions on the autobahn. The car cruises fine and I've had it up to 125mph and had pedal to go.

With the price of gas near $4.00 a gallon, it would be great if my check engine light and my fuel consumption would return to previous conditions. I should also tell you the car was routinely getting 26 mpg when in the U.S., however this was at a cruising speed of 65-70 mph. During my limited on-line research I've found that 1995 models do not require a code reader, however my 1995 does (perhaps it's a late 1995 model).

Thanks for your help.
Perry

A. Your car does have OBD-II diagnostics and 1995 was the model year it became mandatory. Now some 1995 cars could use either a scanner for OBD-II codes or had provision for self diagnosis using the manufacturers diagnosis system. In 1996 it was all OBD-II.

I assume the code you got was P0402. It really helps me if you give me any codes you get. P0402 indicates that the self test has detected exhaust flow at idle. The primary cause of this code is an EGR valve hanging open. But since you replaced the EGR valve, the Differential Pressure Feedback EGR (DPFE) sensor is the next likely culprit.

Differential Pressure Feedback EGR (DPFE)

The (DPFE) sensor is located at the center rear of the engine, near RH side of the intake manifold.