Hey all, My truck is a 2000 F150 XL 4x4 4.6L and it started giving me a p0402 code (Excessive Flow), so I went at it trying to find out how to troubleshoot it down, and found a guide over at easyautodiagnostics so I went at it. I'm pretty sure that my solenoid needs to be replaced, but some of the data didn't line up with what the guide was saying is should be so I'm looking for some opinions on whether I should be concerned or not. It should also be noted that I purchased this truck at the beginning of April and haven't had an issue with it yet. I've also taken the liberty to replace nearly all the fluids, only the Transmission, x-fer case and differentials left , just so I know what I have in my vehicle. The EGR code presented itself about 2 weeks ago.

First was to vacuum test the EGR itself, so I hooked my vacuum pump up on top of it. Vacuumed the EGR to 5hg.-in and the gauge stayed steady, and the engine protested. Tells me that's good and there's no blockages in the TB.

Second was to test the DPFE voltage while applying vacuum to the EGR. This is the first thing that differed from what I had read. The guide I was using stated that there should be a .9V reading while the engine is on and it should increase up 3.5 or 4v at 5hg.in vacuum. My readings started at .4V and topped out at 1.7. Not sure about this one, but the voltage would climb as vacuum was applied, and would drop when the vacuum was released, behavior seemed normal even if the voltage readings were not the same. Time to test the solenoid.

So first I pulled the vacuum lines, and the red line had vacuum, the green had none. This was how it was supposed to be. Next is to test the voltage to the solenoid, it should be 12v. My multimeter came in at 10.7v . Once again not sure what to think here, so I stick my multimeter on my battery to check it's voltage with the engine running, 14.16V. Should probably test that with the engine off though.... Anyways I decide to proceed with the last test and hook my vacuum gauge to the vacuum line running from the solenoid to the EGR valve and go for a drive. I wedge the gauge under the wiper and take off, initially I'm seeing movement and was relatively happy until I noticed that it was going as high as 9hg.in when it should be going to 5 and that's it. Three blocks later nothing, no movement from the gauge when on the throttle... guess that solenoid is bad at least that's the cheapest part between the 3.

So I will be replacing the solenoid regardless, but I'm wondering if I need to take a bigger look at the DPFE and that thing with the 10.7V where there should be 12. Does anyone have any opinions or suggestions?, other than to get my battery tested because that's on the "to do" list as well after this.

Thanks,

 

There are two different variants of the DPFE sensor (depends on vehicle). One uses a .5 V offset , the other a 1 volt offset. Your truck uses the former.

At 5 in-HG, the .5V offset (0 in-HG) sensor should read about 2.7V and should max out around 4.6 volts at ~9 in-HG. Make sure you test the sensor over its full range. If it fails, replace it with the newest revision Motorcraft part before proceeding.

The low side of the EVR solenoids is a PWM signal from the PCM. Various meters handle these signals differently, so the results can vary from the "instructions".

 

Thanks, I just want to clarify then.

Since the DPFE only went to 1.7V at 5hg.in that indicates an issue already and I should re-test it taking it to 9hg.in. A vacuum of 9hg.in is normal, but the solenoid stopping functioning after a few blocks is not and should also be replaced?

I'm potentially looking at replacing both parts then? or it could be that the DPFE is just quitting after a few blocks..?

 

I tend to only go so far as to find the "first" faulty item since I assume that its failure may cause other items to "appear" to be faulty. Once the first failed item is repaired, retest and move forward.

You can check the resistance of the coil of the EVR solenoid with your meter. It should measure between 26 and 40 ohms.

 

Thanks for the help, I replaced the DPFE and went for a 20 mile drive and cruised around town, the error code still hasn't popped up yet. Here's hoping it doesn't ever again.

 

You'll need to wait for the PCM to run the EGR monitor and fail (maybe twice) before it will post a MIL and DTC.

Did you reset the PCM and then, after the drive, check your OBDII readiness monitors?

 

Didn't know resetting the PCM was a thing, so.. nope! If this is the same as clearing the codes with my scan tool, then yes I've done that. My day job is as an IT professional where resetting and clearing are 2 different things, sorry if I'm getting terminology confused.

The code still hasn't presented itself and I've been cruising with it the past couple days trying to give it ample time to pop back up. I'll look into resetting the PCM and into the readiness monitors, didn't know that's a thing either.

 

Just hook up your code reader, if there's a P1000 it hasn't completed readiness checks yet.

 

Ford systems are different than what your It or PC systems do.
By design when a code is cleared it causes the system to go into a complete system diagnostics unlike a PC system that does not go to this extent,normally.
A power down also does the same thing.
Until all the systems pass, a code 1000 is set indicating such.
Some of the reasons why is that it is a motor vehicle and needs to show issues nearly as soon as they are detected.
There are some 2000 codes for fault detection/information stored in the program.
Another is so the system faults cannot be ignored or defeated where emissions and inspection is concerned and hidden.
This system does one thing only and that is the control and self diagnose the engine sensors and output control devices plus general health of the engine.
In many ways a PC does not go this far unless a diagnostic program is specifically run on a part of it's system when something does not work.
Good look.

 

Yeah, no P1000 codes or any other DTC's after almost a week and a tank of gas and the engine's running smoth. It's all fixed, thanks for the help everyone!