Fault Codes

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Oct 23, 2003 | 09:46 AM

Reiner

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From: Kentucky

Fault Codes

Just bought a 96 Explorer with 4.0 V6. Really nice vehicle with 184K mikes. Check engine light stays on. Fault codes (3) show PO133 O2 Sensor, PO401 EGR Flow Insufficient and PO420 Catalytic Eff. below Threshold. Obviously the O2 sensor needs to be replaced. Could it be causing the other two problems, or what else is there to do?
Any help would be appreciated.

Scott

Oct 23, 2003 | 04:03 PM

87 XLT

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From: SoCal

I'm a long ways from an expert, but I think if you correct the EGR problem the other 2 codes might just go away. Might be that you just need to clean the EGR. Good luck with it.

Oct 23, 2003 | 05:07 PM

96explorereddieb

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From: Raleigh, NC

P401 and P402 codes are more likely to be the DPFE sensor. The others...just replace your O2 sensors.

Oct 24, 2003 | 10:07 AM

nasty77f150

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the cat eff. code is from your rear o2 sensor not detecting much of a difference from the front o2 sensor. possibly replacing o2 sensors will fix this code.

Nov 5, 2003 | 10:09 AM

Crazyromi

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From: Philadelphia

I am trying to fix a EGR flow insufficient code on my 96 Bronco, so I found this thread with the search tool. WHat does DPFE stand for and would you know if I had one on my truck? I also have read about cleaning the EGR with compressed air, could someone give me the proper procedure for doing this? Thanks for any help

Nov 5, 2003 | 10:38 AM

Dialtone

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From: South Texas

Well I can supply most of the DPFE acronym for you. Differential Pressure Feedback (something-or-other). It measures the pressure difference across the EGR valve created by its operation and converts the pressure difference into an electrical signal understood by the engine management computer.

As an example, a closed EGR will have high pressure on one side and low on the other. As the valve opens, the pressure on the output side of the valve will rise, and the input side will slightly drop, in proportion to amount of valve opening.
Hope this helps
Dialtone

Nov 5, 2003 | 11:26 AM

Crazyromi

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From: Philadelphia

thanks. upon further searching I found out the definition but thanks for the reply. I don't think my truck has the DPF sensor, but rather just an EGR sensor. Sounds like the same thing. If anyone knows please clarify for me.