EGR Insufficient Flow Check Engine Light

[cmt08]

OK found the egr location. But do you really think that it is a DPRE sensor even after the codes scanned egr insufficient flow? if so where is the DPRE sensor? how easy is it and how much does that cost? also how can I be sure if that is what it is?

 

[Tekreck]

My 02 XLT service engine light came up a few weeks ago. Went to autozone and got code p0402. Did some study here and learned it was most likely to be the DFPE sensor. Replaced with new one from autozone ($26.xx). Took about 15 seconds to do it. Disconnect the battery for 10 minutes to reset everything. Light never came back again.

Same Explorer - same problem - same solution - same result.

 

[matt0248]

The DPFE measures the flow of the EGR Valve. DPFE's were a big problem. There was a TSB on new style DPFE's

 

[Diff Whack Daddy]

I had the same problem with an expedition where the code kept coming back after replacing the DPFE several times. Turned out to be a blocked passage in the throttle body assembly where the tube from the exhaust went into it.

 

[kickitagain]

I had the same problem with an expedition where the code kept coming back after replacing the DPFE several times. Turned out to be a blocked passage in the throttle body assembly where the tube from the exhaust went into it.

Could you expand on this? What tube goes from the exhaust into the throttle body assembly? I thought the tube goes into the EGR.

I can't seem to get rid of code P0402.

So far I"ve changed the following parts in this order:
1) DFPE sensor
2) EGR valve
3) EGR Vacuum Regulator

I have strong vacuum going into the EGR Vacuum Regulator. The hose from the reg to the DFPE holds vacuum. I'm running out of ideas. I tried pushing a piece of wire down tubes that connect to DFPE and can't find blockage.What's next, the PCM?

 

[Gse Brent]

I'm having the same problem and this is the 2nd time it has happened. I replaced my dpfe sensor and cleared the code. Months later the check engine light came back on with the same code. It runs fine except at half throttle it boggs out a little. I'm not sure if i should replace the egr valve or the egr valve vacuum solenoid.

 

[Diff Whack Daddy]

The DPFE sensor controls the EGR valve. Where the tube from the EGR valve goes into the throttle body or intake, it gets gunked up with carbon and blocks the passage. On the Expedition, I took off the upper intake and literally chiseled all the crap away from the port where the EGR entered it.

 

[Gse Brent]

I replaced the EGR valve itself today and it feels like it runs a little better. I cleared the code and went for a ride but the check engine light came back on. Also the new EGR valve makes a ticking sound when i rev up the motor. The ticking stops when i pull the little cap off the top.

 

[Allmost 50]

P0401 code. With only 81,000 miles and driven very gentle I addded a small bottle of Lucas FI cleaner to 1/8th tank of fuel and drove 30 miles flooring it 4-5 times on the interstate from 45 up to 70+ mph. Then added 16oz of Chevron Techron and drove 3 miles where I added 8 Gallons of 93 octane. Drove it 50 more miles with "my foot in it" so to speak. I knew this was drawing at straws. My hopes were the FI cleaner would somehow majically clean the egr tube/valve. Some how my service engine soon light is now off. I have read about all there is regarding P0401 code. If light comes on again I will go a step further.

 

[kickitagain]

Update

Thought I'd give an update.

So far I"ve changed the following parts in this order:
1) DFPE sensor
2) EGR valve
3) EGR Vacuum Regulator

Light was still on so I tried replacing the Advanced Auto DFPE with the original used factory part removed in step 1. The light went out and the code hasn't returned and its now been over 3000 miles. Can't say for sure but I think my problem was step 3 EGR Vacuum Regulator. Big difference, it runs better and my mpg are back where they belong.

170K now and still rolling.

 

[Gse Brent]

I replaced those 3 parts already. I'll try fuel system cleaner and see what happens. But has anyone got a weird ticking sound from their EGR valve when the engine has been revved up? Even with the EGR being brand new?

 

[kickitagain]

I replaced those 3 parts already. I'll try fuel system cleaner and see what happens. But has anyone got a weird ticking sound from their EGR valve when the engine has been revved up? Even with the EGR being brand new?

Not sure about the ticking sound. Did the original have the ticking sound? Really not much to the part. Just a gate type valve as I recall. Sure you have the gasket in place and the bolts were evenly tightened for a good seal?

 

[Gse Brent]

Nope the other one didn't tick and i'm pretty sure i put everything back on right but double checking can't hurt anything.