Help - Check Engine Light P0402 Code
 

Hello. I have a 1997 F-150 Truck, 4.2 8 cylinder engine, 2wd truck with 128,000 miles. 2 weeks ago, the check engine light lit up. I went to Autozone and the code was P0402. Truck seem to be running fine but could smell excess gas. Recently filled up, and 31 miles took about 1/4 tank which indicates quite a problem. Midas wanted $100 for diagonostics. I took it to Ford Dealership in Denver and got the following estimates:

1. DPFE SENSOR ($234 Labor & $141.96 part). ---- $375.96
2. MAF SRV/REPROGRAM - $130). ----$130
3. Fuel Service ($160.59 labor & $59.36 parts) ----- $219.95
4. Fuel Filter ($37.95 labor & $22.00 part) ----- $59.95
5. Coolant Flush (63.32 labor & $57.63 parts) ----- $120.95
6. Power Steering Flush ($35.69 Labor & $46.36 -----$ 82.05
7. Brake Fluid Flush ($45.87 labor & $44.08 parts) --$ 89.95

All with taxes and shop fees $1,145. And conveniently I was approved for $1200 Ford Credit card.

The truck was tuned up with new spark plugs and wires at 100K mark.

Here is my question, what should I do? If the dealership is correct, I plan on doing the first two. But I plan on taking it to a reputable repair ship as I think the parts and labor for the DPFE sensor are out of whack. When I left the dealership, I asked if the EGR valve was fine and he said it was.

PLEASE HELP. ANY ADVISE IS VERY HELPFUL.

Billy

Ya know, this is shamefull!
First of all you have no idea of what is going on!
Your ignorance is being taken advantage off.
Look up the 402 code.
It discribes an excessive flow test code in the EGR system.
The EGR system consists of a tube from one exhaust manifold to the EGR valve.
In that tube is an orfice.
The DPFE is a pressure sensor that measues the pressure drop accross that internal orfice.
Since the code is telling that a pressure drop was detected when there should not have been a difference measured accross the orfice, it is the 'Excessive flow" that is being reported as the 402 code saying the system is not 'tight'.
What could be the problem.
1. Leaking EGR valve.
2. Vacuum gate valve allowing vacuum to operate the EGR causing the leak.
3. The tube has a crack or hole.
4. The DPFE or it's hoses are leaking.
This only involves one system, not the whole list the dealer told you and the expense.
Some of the rest may be needed as service on a high mileage truck but it's not related to the code you have.
You need to find a tech to repair for the code only, then address any other issues you think you may have.
Hope I have helped you to understand where things is at so you don't get skinned out of a lot of money needlessly
DPFE is less than $100, and easy bolt on/off.
The vacum gate valve is about the same.
EGR may be a little harder coming off.
The tube is more of a pain on an older truck due to rust etc.
A test of each part of the system will tell where the problem is then replace that part.
Clear the code, do two drive cycles and see if the code comes back.
Reason for two drive cycles is the system must test fail two times in a row for the code to be set gain.
The test is done on cold startup and drive away acceleration when the exhaust pressure is high, for a good test.
You now have the basic info. What you do with it will be the difference.
Good luck.

I AGREE WITH BLUEGRASS 7.I SEE THAT THEY WANT TO CHARGE YOU 234$ IN LABOR TO REPLACE THE DPFE.MY CHILTON LABOR GUIDE STATES .6 OF A HOUR.IN NY SHOP THAT WOULD BE 30$ TO REPLACE IT.ALL OF THE SERVICES THEY ARE TRYING TO CRAM DOWN YOUR THROAT IS REALLY SAD.GO BUY A DPFE AND INSTALL IT YOURSELF.IF MY PICTURE IS RIGHT IT IS LOCATED ON THE PASSENGER SIDE OF THE ENGINE AND IS BOLTED TO THE INTAKE.IT HAS 2 HOSES ATTACHED TO IT AND 1 3 PIN CONNECTOR.DISCONNECT THE BATTERY AFTER THE INSTALL FOR 10 MIN AND SEE IF IT COMES BACK ON.

It's probably your dpfe. The same thing happened on my 99' f-150 5.4 v8. What I think happens is the exhaust gases erode the medal sensor. Its really an easy fix if u know how to use a ratchet and screw driver. I think the part was only about $40 dollars. If you do it yourself just make sure to clean out the hoses connected to the sensor.

As noted, it probably is the DPFE sensor. The rest of the stuff on the dealer's list (except the MAF "service", whatever that is...) is "routine" maintenance that wouldn't hurt on a 13-year old truck, but can be done by any competent DIYer or service shop.

However, do yourself a favor and buy the upgraded Motorcraft part. It's twice as much as the one from the auto parts store, but, over the last few years, there have been so many posts regarding short life-span of the ones from the parts store that it's almost impossible to predict how reliable the cheaper ones will be. The new Motorcraft sensors seem to be holding up well after several years' operation.

It's amazing how you can gleen so much information from one DTC(P0402). It's usually P0401 on these Fords. How extensive would the repair bill have been if he had the more common P0401. I'll bet the intake would have to come off. How does this happen at your local dealership? Is this a conspiracy? Does the owner tell the manager to generate revenue who tells the service writer to order unneeded repairs who tells the mechanic to do them and he completes the work order knowing most of the repairs aren't needed other than the power steering fluid flush(I'm a big fan of changing fluids to avoid having to change parts down the road) and maybe the DPFE? Ford has made millions on the out of warranty EGR codes. Imagine how different the work order would have looked had this vehichle still been in warranty? At least this owner had the good sense to ask if this was a scam, but what about the poor little old lady with blue hair. She probably doesn't even know about this site or how to get to it.