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PostSlut
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13,597 Posts
Discussion Starter #1
Wife recntly told me her check engine light came on in her taurus.
pulled the codes, and got a p0402...excessive egr flow detected. the car runs a little rough like it has a miss.....but not always either.

Seems like it could be a faulty selonoid, or dpfe.

anyone have experiance with the 3.0L vulcan?

(I believe the fix on this would be like for an mn12...but not sure).
 

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PostSlut
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13,597 Posts
Discussion Starter #3
First thing I would do is check vacuum to the valve at idle. There should be none or very little. Then check the valve itself. Make sure that when closed nothing can flow through it. If that checks out, it's likely the DPFE.
thanks Chris....I did not have time this weekend to look at it.
But will check it out later at home.
 

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Before replacing anything, pull the EGR valve off and clean all the ports out. When it gets clogged up with carbon, it usually throws a code for insufficient flow, but if a chunk of carbon gets stuck in the valve and prevents it from closing all the way, it will cause it to run rough and throw a code for excessive flow. If everything checks out good with that, I would go to the DPFE sensor next.
 

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PostSlut
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13,597 Posts
Discussion Starter #5
Before replacing anything, pull the EGR valve off and clean all the ports out. When it gets clogged up with carbon, it usually throws a code for insufficient flow, but if a chunk of carbon gets stuck in the valve and prevents it from closing all the way, it will cause it to run rough and throw a code for excessive flow. If everything checks out good with that, I would go to the DPFE sensor next.
will do Mike.

thanks.
 

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A P0402 means you have flow at idle, so there are no restrictions.

Feel for a very slight,weak vac at idle at the EGR vac line(this is normal). If this vac is above .5 HG your solenoid is bad and holding the valve open.

Monitor DPFE voltage at idle with a scantool or mulitester at the DPFE terminal. (one terminal is ground, other Vref 5Volts, third DPFE).

Should be .5 or 1 V at idle (either value is fine). Anything more is suspect (you have EGR flow due to a bad valve or a bad sensor.)

Use a mityvac to open the EGR, DPFE voltage should rise smoothly and drop back as you apply/release vac. Valve should open with 1 hg. It is a perfect linear relationship till about about 8 Hg.(where it will read 5V I believe) If that is the case your sensor is good.

Next take off the the EGR and clean it, the one on my tbird would not clean up and you could always blow thru it. The new one had a perfect seal.
 
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