P0401 and EVAP

[DRW1000]

Thanks ModMech (and Rodeo2),

Yeah I had a really difficult time getting the EVAP monitor to run. It can only perform one of the tests within 30 minutes after an 8 hour soak and the air temp has to be above 4.4C. I have a hard time getting to a highway in non stop and go traffic so I needed a weekend to run it.

I feel pretty confident now.

Thanks alot

[DRW1000]

Well it passed easily.

Thanks to everyone for their help

[akkhandelwal]

I have similar symptons as you had. I checked the EGR valve valve by applying human vaccume and the engine started to stall. It shows that the EGR valve is not stuck and the ports are open. When I check the voltage at the sig rtn pin at the DPFE, the voltage is .4 and it never changes. As per Chilton's book, is should change to over 4.0 volt.

I bought a new DPFE sensor at autozone and tried it . It also gives the same readings and no change in voltage even when I apply human vaccume at the egr port and get a flow thru it.

I dont understand how you were getting 4.67 volts with no flow. Which pins you were testing the voltage? Also it will help if you could explain how to bench test the sensor.

Appreciate your help.

Thanks

[akkhandelwal]

I have one more question.
Is it possible to clean the EGR valve by injecting the carb. cleaner through the upstream port connected to the sensor.

In 98 windstar, it's pain to open the EGR valve because of its location. This seems to be an easy option to inject cleaner through the upstream port
connected to the sensor and then manually apply vaccume to the EGR valve to make it open the port and suck in the cleaner. This way one can clean the EGR ports before they are fully clogged.

I will welcome comments on this option.

Thanks

[akkhandelwal]

Update to my previous posting:

The chilton maual shows wrong pin to be tested for voltage change. Actually it is not the middle pin as shown in the manual. I was able to get the variation with the sensor I bought from autozone.

I am still waiting for a response how to bench test it after opening my old sensor.

Thanks for your help.

[DRW1000]

My apologies for waiting so long to to respond. I lost all of my favourites and I forgot the address to this forum.

If you still need help troubleshooting your DPFE let me know

[akkhandelwal]

Thanks for responding.

I was hoping to get some guidance how to bench test the sensor. I opened the rivets and also arranged a 5 v DC source, but could not go any further.

[DRW1000]

I assume that you are just looking at it for interest sake and the replacement is on the vehicle and working fine.

If so you need to power the DPFE with 5 Volts DC. The sensor has a reference voltage pin, a signal pin and a ground (or common). Put 5 volts across referenc and ground. (+ to reference) . Using a voltmeter measure the voltage from signal to ground. I got a replacement at a junkyard and I also cut off the connector from the junk car and it came in handy for connecting wires.
Push one of the pads the you see. (these are the pressure transducers). as you press them you will see the voltage change in relation to the force you apply. You may have to try the other side as it measures pressur on both sides.

On my sensor I discovered that the wire that goes from the outside (spade terminal) through the body of the sensor (through potting) and to the circuit board had an open circuit. I cut the potting and re-ran the wire and it has worked great since then

[g8rjeff]

Thanks to all who have contributed... this is an very informative thread.

But this novice has a couple simple questions...

1) How hard is it to remove the EGR value?
2) How do you clean the EGR value? What type of cleaner?

If #1 or 2 doesn't work...

3) How hard is it to remove the DPFE sensor?
4) Does the Chilton manual (or others) show how this is done?

[DRW1000]

Depends on the year. On my 99 the EGR to Exhaust input tube is hard to remove. other than that it is pretty straightforward.

The DPFE is a 10 minute job to remove.

The Haynes I have for my car outlines the steps very clearly

[from]

Ford has initiated an extended warranty program for this part (DPFE part# 9J460) for an additional 40,000km or 2 years whichever first) The program number is 02M01 started February 2003.

At least they acknowledge a problem.