code P0402 excessive exhaust flow?
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VT Chapter Ldr
Joined: Apr 2004
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From: Orange, Vermont
code P0402 excessive exhaust flow?
The mechanic said the problem was the DPFE but the 96 v8 does not have one so I replaced the egr and the sensor that bolts to it and the check engine light came back on. I borrowed a scanner and the code is P0402 exhaust gas recirculation flow excessive detected, then it has four ovals that are flashing which are cat, o2s, htr, eva and up in the corner it says pending code 02.
So any gueses what else or how to check.
So any gueses what else or how to check.
Hotshot
Joined: Mar 2007
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From: Pa
If the "Silver" thing that bolts to the intake manifold has tubes coming out of it and is rectangular thats the DPFE. I'm not real familier with the 5.0l in explorers but if its got EGR I'm shure it has a DPFE.
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VT Chapter Ldr
Joined: Apr 2004
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From: Orange, Vermont
The Hayse repair manual says that 95 v6 and 96 v8 explorers do not have the dpfe, and I didn't see any retangle boxes with tubes coming out of it. A couple others on this forum also said the 96 v8 doesn't have one either. The code reader I believe did mention something about bank 1, so maybe it is the o2 sensor? Will need to put the reader back on and look at it agian.
Hotshot
Joined: Jan 2004
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From: St Louis
Check the EVR solenoid to see if it is passing vacuum to the EGR valve when it shouldn't (at idle, for example). If it is, replace it.
The 95 and 96 5.0L in the Exploder uses an EGR valve mounted EVP sensor, not a DPFE sensor.
Uncommanded (excessive) EGR flow can cause other ODBII faults, notably those relating to mixure control (ie, O2 sensors).
Fix the EGR problem, then reset and retest before going on a wild goose chase.
Those flashing ovals on your code reader simply mean that the I/M Readiness Monitors for those functions have not successfully executed. Disregard them at this point, they're only critical if you're trying to pass a mandated emissions test that relies on OBDII system status.
Steve
The 95 and 96 5.0L in the Exploder uses an EGR valve mounted EVP sensor, not a DPFE sensor.
Uncommanded (excessive) EGR flow can cause other ODBII faults, notably those relating to mixure control (ie, O2 sensors).
Fix the EGR problem, then reset and retest before going on a wild goose chase.
Those flashing ovals on your code reader simply mean that the I/M Readiness Monitors for those functions have not successfully executed. Disregard them at this point, they're only critical if you're trying to pass a mandated emissions test that relies on OBDII system status.
Steve
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VT Chapter Ldr
Joined: Apr 2004
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From: Orange, Vermont
Thanks projectsho98 for the info. Where is the EVR solenoid and do you pull the vacuum hose off and check it or is there a test procedure written somewhere?
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Hotshot
Joined: Jan 2004
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From: St Louis
Pull the vacuum line off the EGR valve and see if there is any vacuum there while you are in your driveway at any engine speed.
That hose goes to the EVR solenoid.
Steve
That hose goes to the EVR solenoid.
Steve
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VT Chapter Ldr
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From: Orange, Vermont
Thanks projectsho98, I actually replaced that hose at the same time but will pull it off to check for vacuum. I assume I could just stick my finger over the end to check it. I am still a little confused, should it have a vacuum at higher engine speeds and not at idle or are there other rpms it should not have a vacuum?
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Joined: Jan 2004
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From: St Louis
It should only have vacuum when the computer tells the EVR solenoid to switch on (variable duty cycle). This should only occur during steady-state cruising and should never happen in your driveway.
Steve
Steve
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VT Chapter Ldr
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From: Orange, Vermont
I checked it this evening by pulling the little black hose off the egr housing and sticking my finger over it. At idle it did feel like fast pulsating vacuum, which it sounds like there should be none. From what you have described it sounds like the EVR is very likely the culprit, unless there is a problem with the computer 
.
.
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VT Chapter Ldr
Joined: Apr 2004
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From: Orange, Vermont
I just changed what I believe was the evr selonoid, the black plastic housing that the vacuum hose from the egr to it. Unfortunately it still feels like a vacuum at idle and the check engine light came back on with the same code. Any more ideas? Thanks.
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