RedFX4

hey all. i have a trouble code P0191 - Fuel Rail Pressure Sensor Circuit Range/Performance... And yesterday the Fuel Pump Driver Module started acting up. are they related? i just ordered a new FPDM today for $120. I hope this solves it because i just replaced the fuel rail pressure sensor that was throwing the P0191 code last time and it got better for a while and now its back again. if someone can help id be very appreciative. thanks!

Mod (Ret.)

I can say that the fuel pump driver module is what enables/disables the fuel pump. Our Ford trucks (2004 to 2008) use a single fuel line from the gas tank to the fuel rails that feed the injectors. The fuel rail pressure sensor sends a signal to the PCM to let it know if the required pressure is at the fuel rails. The PCM informs the fuel pump driver module which in turn "turns on/turns off" the fuel pump.

This system replaced the dual fuel line setup that used to be used, controlled by a fuel pressure regulater that routed fuel back to the fuel tank. The newer system is used to prevent dual fuel lines (safety during a crash), as well has the fuel heating up and being returned to the tak causing additional fumes (an EPA thing).

The fuel pump driver modules are another common failure point because of their location: on a frame rail at the spare tire area. Road grime, salt from roads in the north cause this module to literally rot; some that have posted here have stated this module fell off, crumbled, and was badly coroded. As you may have already found out, there is a 20 to 30 day back log on these parts. About two weeks ago I found that the Ford Expedition uses the same module under a different part number, and that there was a Ford dealer in Ohio that had some. A couple of folks called and got one within a day or two shipped; got their truck back on the road. The Expedition has two threaded studs pressed into the module as well as the same holes in the same place as the F150 module; the F150's use two bolts to mount it against the frame rail. It is strongly recommended that you place a couple of washers between the new module and the frame rail to keep the water, salt, and other road grime from building up and rotting the new module. With the Expedition module, you can just grind off the threaded studs, which then leaves a 1/4 spacer to keep the module off of the frame rail when you bolt it up using the two bolts from the truck.
I posted the part number and phone number in a thread (about three or four weeks ago) with this info.

RedFX4

thanks for all the info Bucko. i got the new FPDM today in the mail and i just got it replaced. there was a hole in the back of the old one. i plugged in the new one bolted it up and checked for codes on startup. so far after running for 30 minutes NO CODES! so as far as i can deduce, the FPDM was not working properly and so the P0919 Code was thrown. I will keep this updated and if anything changes i will let everyone know. btw the Fuel Rail Pressure Sensor i bought 2 months ago was $87 from the dealership. i got the new FPDM for $120 from ebay.

Also on a side note.. that infamous clunk from under the truck coming from the engine went away tonight after i replaced that module too.. idk may be nothing but just an fyi and i would recommend everyone check that darn thing and make sure its not corroding. its an 8mm socket and dropping the spare tire. checking it and putting a few washers in there may save you $120!!

plucroy

What is the part number for that fuel module ?
Thanks

Mod (Ret.)

Search it here. There is a post that will provide the Ford F150 module part number (on back order for most dealers) and the Expedition part number.

plucroy

Yeah, I've found it on one of your post .
Thanks !

wayner147

So just so i understand i have the fuel rail pressure senssor range error coming up and my truck wont start like its getting no fuel...so therefore all i have to do is change the fuel rail pressure sensor loacted on the fuel rail?

Does anyone know how much canadian one cost?

And is this def the issure if thats the error im getting.

OldSchoolFordMan

When the Fuel Pump Driver Module (FPDM) corrodes through the back side you may not get a code at all. But when the housing is so corroded that it leaks to the atmosphere moisture and debris get inside and destroy it completely. Then the fuel pump totally stops and the engine quits. It may still get a "prime" signal to get some fuel to the fuel rail when the ignition switch is turned to on position (about 1 - 2 seconds) but will not pump fuel after the prime signal. When that happens you'll get a P0191. The code indicates a problem with the fuel rail pressure but there could actually be a few different causes: 1. Fuel Pump, 2. Fuel Pump Driver Module, 3. Open circuit or short in the fuel pump wiring harness, 4. Clogged fuel strainer or ice (don't laugh) around the fuel strainer/pickup, 5. Fuel Rail Pressure Sensor or a vacuum leak on the line that connects to the sensor, 6. Could be other causes. In my experience with Ford dealers I've found that 90% of the time they will replace the Fuel Pump ($620+), and then the Fuel Rail Pressure Sensor ($229) before they discover the problem was actually the Fuel Pump Driver Module (DIY: Advance Auto or O'Reilly $104 plus tax). Before doing anything serious, check and reset the fuel cutoff switch and fuses #32 and 34. If you only get a P0191 you may have both Fuel Rail Pressure Sensor ($114 plus tax) and Fuel Pump Driver Module ($114 plus tax). Pressure sensor is a 10-minute, 2 bolt swap out and the FPDM takes about 1/2 hour because you have to drop the spare tire to get to it. Bottom line: If you get both a P0190 and P0191, 92% of the time it's the FPDM. If you only get a P0191, 84% of the time you need the FRPS and a FPDM. The dealer will replace all these parts (pump, module, sensor) for about a grand and they may also want to replace things like COPS, PCM, OS, etc. Don't throw away your hard-earned money - fix it yourself for around $225 and less than an hour of your time. PS: These trucks (F150 04 - 08) had a design flaw with the FPDM being aluminum/zinc with steel bolts going into steel chassis member. You can't see the corrosion until you take the module off. The back-side probably will be so corroded that it has a big hole in it.

Todd W

I'm having issues with this P0191 code on my 2005 ford f150 lariat 5.4

Dealership changed throttle body, and it did nothing. New fuel pressure sensor didn't fix either. The FPDM is in good shape.

Ford has had the truck for 2 weeks now and still have no answers. Nothing but the 700$ they charged me for the throtttle body replacement, that did nothing.

techrep

iTrader: (1)

Why would you let them charge you for parts that did not fix your problem ? How do you know the FPDM is in good shape ? did you remove it and take it apart ?