The service engine soon light has shown its ugly self, I have a 2002 f-150, 4.6 l
engine with 45,200 miles. Looking in the service manual, I see that I should have the engine coolant changed at 45,000, is that why the nasty little light has show itself?

 

This might sound silly but,what grade gas are you using? I went to regular because of the increase in prices. Well, I think the lower octane made my light come on so I added some octane booster. My light has since turned off shortly after adding the booster. I have a '99 F150 4.6 extended cab with 107,000 miles. This truck has been very dependable for the five years I've own it.

 

Go to Autozone or another local parts store. Most will pull the codes for the CEL for you for free. Good starting point.

 

Coolant that needs changing will not cause a CEL. The light is not programed to come on at any interval, it only comes on when the computer detects an operating or self-test parameter that is out of range.

Likewise, the octane of your fuel cannot cause a CEL by itself. These engines were designed to run on 87 octane. Consult your owner's manual for clarification.

The only way to determine why the light came on is to read the code(s) as BillyBob69 suggested. If you take it to a chain store, make certain that you right down the EXACT code number(s). They will be in the format of PXXXX where XXXX is a 4-digit number including leading zeroes.

Once you have the code(s), come back here and perform a SEARCH using the code(s) as your search keywords. If you need further help after researching the code(s), just ask.

Steve

 

That's wierd. These trucks a designed to run on 87 (except for the supercharged engines). You might have some underlying problem.

 

Thanks, I Have An Auto Zone Store Close To Me And I Will Take The Truck There To Have The Codes Read Out. I Will See What They Say And Get Back
To The Forum Also. Will Post The Code Results Next Week.

 

You will probably get a 0401 code, which I have on my '02 with a 4.6. I think there is a service bulletin related to the DPSE sensor which may be causing the problem.

 

Robbywayne

What is the DPSE sensor?
Did you have the dealer or another shop fix the problem?

 

It's "DPFE" DPFEGR - Differential Pressure Feedback Exhaust Gas Recirculation. A system that uses a pressure transducer to control the operation of the exhaust gas recirculation (EGR) vacuum regulator valve.

It's very easy to change. If you need a DPFE sensor then try these guys. It was $56+ shipped and the dealer wanted $108.00.
http://www.trademotion.com/partloca...m?siteid=214126
Disconnect the battery for 15 minutes or so (and turned on the headlights to drain memory), loosen the two nuts, pull the two hoses (make sure that you don't mix them up) install the new one, reconnect the battery and you're done!
You may have the free floating DPFE so disregard the nuts.

First, you need to get the codes read as projectSHO89 & BillyBob69 have suggested then go from there.

Good Luck!
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Thanks, I'm going this week to get the code.

 

if it's the DPFE senson the code will be a P0401 or i think P0402......i got my new DPFE sensor from my buddy that works at the local ford dealer for 16 bucks.......so, figure out what the code is then post it on here and we'll help.....if it's a P0401 or 402 it either the EGR valve, cabron buildup in the intake manafold or the DPFE sensor.....most probable answer is the DPFE sensor.....cause from what i'v been told they were all crap from ford and most of them should of been replaced by ford but they werent......it's very simple to do so let me know if thats what it is


PS: if it's a P0401 take the hose off the top of the egr valve and just apply suction to the egr valve by connecting a small diamater hose to the top and sucking on it.......if the egr is working and the pasages are clear the truck should stumble or almost shut off.....if it stumbles then it's the DPFE if it doesn't stumble and the idle stays the same then it's either the EGR or the pasages are cloged

hope this all helps

 

Went and got the truck tested for the code last night.
The reading came up P1401.
Looking it up on the internet I found a site that says it's
the DPFE Sensor High Voltage.
Is this correct and if so any ideas how to fix it?

 

go buy a new DPFE sensor.......then install it....it's prolly located on the right side of the motor back near the firewall.......it's about 5 inches to the right of the block......it has two hoses comming up to it and a plug in the front of it......just pull the hoses and unplug it and re install the new one.....it's very easy.....then take the battery off for a while so the computer resets then put battery back on and the light should be gone......and questions send a message


i got mine from a buddy that works at a ford dealer for 16 bucks.....their cheap so just replace it

 

Thanks gui88ford

I'll get to it this weekend and let you know how I make out.

 

Finally was able to get the sensor.Had to go to ford, the aftermarket places couldn't figure what the sensor was. Anyhow, 25 dollars later, fords price, I replaced the sensor, and everything seems to be fine now.
Thanks to everyboby for the advice.