Contour Enthusiasts Group Archives Forums General Troubleshooting P402 [excessive EGR flow]... follow-up

I cleaned out my intake manifold passages today and there wasn't much to clean at all. At 96,000 the passages were almost spoltless [I cleaned out the throttle body nevertheless]. Ok, so it definetly wasn't the clogged passages that were the problem, since the check engine light is still on after driving around for a while. What should I try next?

O2 sensor...

You have a PM......

P0402 - excessive EGR flow at idle

cause: DPFE sensor

check it out and test it that should be the problem

I have a post from I think 2 summers ago about this and in there it will tell you how to check the EGR valve and if it passes it is the DPFE

EXCESSIVE EGR flow will likely be one of the following:

Faulty EGR Valve - not closing fully
DPFE Sensor - Measuring incorrect amount of EGR Flow
EVR Solenoid - Applying constant or excessive vacuum to the EGR valve

This is not an issue with the throttle body ports (That's a P0401).

Steve

I couldn't find the post where it said how test the EGR valve, anyone have a link to that?

DPFE Sensor... How exactly does it affect my car performance? Is this really something I should replace [I just passed smog two weeks ago and I don't really care if the cell light is on or not]?

.. Also I'm looking at how much it costs and there are two kinds of EGR Sensors:

EGR Valve Position Sensor
and
EGR VALVE PRESSURE SENSOR

I assume I need the Presure sensor... Well they only have it @ Autozone (SU282) and it's $54 + shipping. Anywhere else I should look? Thanks ahead of time

This was just covered a few days ago.

http://www.contour.org/ubbthreads/showflat.php?Cat=&Board=trouble&Number=902522&page=5&view=collapsed&sb=5&o=7&fpart=1

this was the post I was talking about

2000 Mystique LS (Duratec 2.5), 88K mi
Normal service (no emissions system cleaning or tinkering yet), nothing notable in vehicle history

Started car yesterday morning after 14 hours of inactivity, drove 1-2 miles (~3-5 min. of runtime, 0-50 mph and a couple stoplights) and check engine light came on. Drove 14 more miles and parked. 9 hours later started car and drove 15 miles, grabbed scan tool and retrieved code 0402 (egr excessive flow), reset code, parked car. 14 hours later drove car 15 miles and parked. 9 hours later started car and drove 1 mile (5-7 min. of runtime, 0-40 mph and a few stoplights), check engine light comes on again while stopped at a light. Code again reads 0402. Car runs normally (just fine) at all times, idle is steady, etc.

Based on this information, what is the most direct and cost effective way to hunt down the problem? I have searched all the posts on the forum but wanted to know what you guys thought since these symptoms (other than the CEL) or lack thereof are a little different than the other posters'.

Thanks!

Welcome to CEG!

This is almost invariably a bad DPFE.
It can also be a clogged metering port in the EGR tube to the exhaust manifold, but that is rare.
The EGR valve and EVR would normally give you a bad idle.


To test for yourself you would need to measure the output of the DPFE. Provide an E-mail and I can send you something on that.