Wednesday, January 8, 2014

Jackass Award - GM Pickups Fuel Pump Control Module

2009 Chevy Silverado plow truck (with apologies for the CCTV-screencap image quality)

First, a bit of a back story. Electronic fuel injection was just hitting the mainstream when I began working on cars for pay (rather than to avoid paying...) just over 20 years ago. There were several different strategies involved in feeding the systems with fuel, all of which involved at least one electric pump. To prevent the pump from running unnecessarily after a stall, a crash, or just sitting with the key on, the pumps were usually switched on by either the engine computer (through a relay), an oil pressure switch, or both (early GM systems especially).

Most had a single in-tank fuel pump that delivered a constant feed of fuel at a pressure governed by a regulator (usually throttle-body or injector-rail mounted and vacuum controlled) that bled any excess fuel back to the tank through a return line.

Others - most notably the Europeans - would use a low pressure feed pump in or near the tank to supply a second, high pressure pump that ultimately accomplished the same function as the single-pump setup.

The odd vehicle had the ability to vary pump speed, usually through a dropping resistor, or via high frequency voltage toggling (known as pulse-width modulation). This was done primarily to reduce pump noise at low speed and idle, when demand was low and ambient noise less likely to disguise the ruckus.

As technology has introduced more precise injection control, a large number of vehicles have gone to what are called "returnless" systems, where there's no longer a second fuel line coming back from the engine compartment to return excess fuel supply. A single line simply supplies fuel at the required pressure to the injector rail. This eliminates some parts, but most importantly, prevents the fuel from being warmed by engine heat prior to its return to the tank, which apparently offers benefits in emission reductions and possibly even power production.

Often there's a fixed pressure regulator in the tank or a nearby filter/regulator assembly to make this single line system possible. Others vary the fuel pump's power supply to control its output and therefore pressure, usually with feedback from a fuel-rail pressure sensor. This is where our Jackass Award story begins.

An important note: GM is not alone in using the basic design I'm about to discuss. Ford trucks are well know for fuel pump control module failures, for example. But some questionable engineering choices do make the one used on GM's recent model year full-sized pickups - the example featured, the first of these I've encountered, is a 2009 model - Award-worthy.

This seemed like a good idea to someone...

The above photo shows where GM chose to locate the Silverado's (and the identical Sierra's) FPCM (Fuel Pressure Control Module), just above the spare tire beneath the box at the rear of the truck. Ford is equally guilty of mounting the fuel pressure control module where corrosion will eat it. They were doing it well before GM decided to follow suit. Hey, if it didn't work for Ford...

To diagnose this thing, most of the trouble code diagnostic "trees" require you to unplug this connector. The lid swings down to unlatch it - impossible, by about an inch, with the spare tire in place. Ever lowered the spare on a modern pickup?

Rube Goldberg would be proud

I have. Fortunately, this truck , in spite of being used for plowing snow and landscaping, is well-kept, clean, and not a big muddy ball of corrosion, so the process was only slightly aggravating: find and extract the toolkit (often buried or missing), unlock the spare tire lock (good seize-in-place potential), assemble the correct sequence of crank segments (instructions? Who needs 'em?), spend a few minutes trying to get the tool to align and function in the winch (you'd think the built-in guide would make that a first-attempt thing. It doesn't.), crank the spare down.


Finally able to disconnect the connector, we verify that the module has failed and needs to be replaced. Surprise! Our local dealer has one in stock.

On the vehicle, this view is only possible with a mirror, a boroscope, or a cameraphone jammed up against the floor of the box. Nice corrosion.

If you look closely at the spare tire-view photo, you can see that the module is fastened to the bracket it's mounted to from above. A Jackass Award qualifier. Extra Jackass points though because the fasteners in question are rounded-head Torx bolts with fine threads - seen from the top, after mild, fruitless digging out with a pick - in the above photo. The three of those are not coming out without a level of personal attention that's all but impossible in-situ.

Another cameraphone-aided view. Only my hand could see this otherwise. Thank goodness for ratcheting wrenches.




The FPCM is mounted to a large bracket that also holds the TBCM (Trailer Brake Control Module) and another small electrical component. It bolts to the left frame rail and the spare tire winch mount. Fortunately, its three fasteners have conventional hex-heads, though, in true Jackass form, they are also top-mounted, and the winch-side one is conveniently and for no apparent reason located directly beneath the pickup bed's reinforcement beam. There will be no using air tools or even a ratchet on those. Nice. (At least this particular truck was mud and corrosion free.)

Voila!

I think I may have peed...

Once extricated from its bracket, the FPCM peed on our bench. Actually, I was glad to see this, because condemning electrical components can be stressful because you usually can't see anything wrong. Water leaking out? I'm feeling pretty comfortable with my diagnosis! It may need more, but it definitely needs this.

Note that the silver side seen above is the top. The plastic tub forms the bottom, making a decent water-retaining bowl. Obviously the thin layer of sealant wasn't enough to keep the water out (or in). You surely wouldn't want to mount it the other way, and give it a fighting chance.

Carefully opened afterward with a 24 oz ball-pein hammer, water can be seen inside. Think those IC chips like water?

The new one has a thick bead of sealant oozing out of it. It got new bolts too, though they didn't come with it.
So we get our new module, mount it to the bracket, fish the bracket's top-mounted fasteners back in and ratchet-wrench them tight, successfully clear the trouble codes, crank the truck, and get...  ...a brief fire-up followed half a second later by a stall and refusal to restart.

Recheck the codes to see what else is wrong, and see..

That's not good.

... that the FPCM needs to be programmed. It's a several hundred dollar box of rocks without the proper software. The common-failing Ford truck fuel pump modules don't need this. They're even available from the aftermarket, plug'n play. Not this one; the final, Jackass Award-clinching move.
Shouldn't have been a surprise, actually, because in this generation of GM pickup, even the power window switches have to be programmed when replaced. Got an identical, same year truck, identically optioned, and want to temporarily swap the switch to put a window up when the original switch breaks on a -25ÂșC day? Won't work - not programmed to that truck, as one of our tow-truck fleet operators discovered, to his extreme pleasure.

Money, money, money...

At this point there are a couple of options.
- Tow the truck to a dealer (what GM would clearly like you to do, though they'd probably be happier still if their dealer had diagnosed and replaced the module in the first place).
- Tow the truck to a shop that has GM programming capability (which they have to pay to subscribe to - GM is still making a smiley face).
- Program it yourself. Assuming you have the several thousand dollars worth of equipment and/or software to do it, of course. You will also have to pay GM a subscription fee to access the download. $55US gives you 2 days of access to that content, for example, so GM still wins.

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For designing a vehicle that even requires a stand-alone module to operate the fuel pump, then making that module vulnerable to moisture intrusion and mounting where such intrusion is virtually guaranteed (particularly in a vehicle type that frequently gets operated in exaggerated conditions), then making replacement of the module physically difficult by fastening it with corrosion-prone fasteners mounted on the backside of a bracket sandwiched beneath a pickup box (rather than just attaching it from the underside), and ultimately requiring that said module then be programmed for the simple task of running a fuel pump - General Motors, I'm forced to hand you a Jackass Award.

44 comments:

  1. Great article... and right on point.... especially now that I'm experiencing this "hell trap" at the current moment.

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  2. Same problem and headaches that your having, mine pissed water, now im having it towed to dealer after I did the install... PITA

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  3. Very accurate account of G M fuel pump module. We learned the hard way that it had to be programed after changing. What a stupid place to locate it.

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  4. The exact same problem here in the UK, the problem is right across Europe. It,s what I call big multinationals having their own way at the expense of the driving public, so much for freedom and democracy what happened?

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  5. Thanks for the info
    You have convinced me...a life long GM guy is finally tossing in the GM towel. After my GM dealer experience when shopping for a new Chevy PU (2015) , I realized nothing has changed with the "faulty key switch" mentality. Now reading how programing is required for all the usual Do it yourself servicing, it time to change sides...
    Ford or foreign..anything BUT GM ...especially after an otherwise 2 great ECOTEC engined Sunfires, it is the GM the factory stuff such as the wire loom that rots etc etc that is the bad , non-recalled , premature GM failings ..
    Now new technology now makes it even easier for them to charge more for simple repairs - now that they are dealer only repairs?...see ya GM..and good riddance!
    as much as I am sure Ford has its problems, its the GM culture of "screw the customer" that I am leaving...

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  6. I took mine off and removed the back plate to also find some water. I thought I would try and dry it out beforeally buying a new part (yes I am tight with my money). I put it I an welding rod oven on the lowest setting for 5 hours. Took it out and reinstalled it and it works. Saved me $400.

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  7. I am getting the "run-a-round " as we read ! For 3 years, GM refuses to accept responsibility for my "headaches". I first purchased my vehicle from a dealership who failed to replace the Fuel System Control Module (although they were aware of the recall) before I purchased it. Since then, I have had "no start " after "no start", even after one dealership "claimed" to have repaired it. I even talked to a few "Senior Supervisors" at GM, who boldly told me " We will deal with it, THEN !" , after I insisted there were problems with my truck and gave two scenarios (1) What happens if I am involved in a major accident due to the "no start"? or (2) what happens if I am seriously or fatally wounded due to the "no start/stall"? I would like to see them allow their loved-ones ride around in their "death-trap pieces of crap" and see how quickly they move to repair them. It pisses me off to know how the customers are getting treated especially since it was our money that bailed the auto industry's @%%&$ # out . PISS-POOR product and PISS-POOR service ! This was my FIRST AND LAST CHEVROLET PURCHASE!

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  8. This was a great write-up!!! Without this article and IdentiFix, I never would have found this. The 2008 Silverado sitting in my shop has a crank no start but will run on starting fluid. After busting open the Fuel Pump Module, it had traces of moisture in it. Shame on GM for making this proprietary piece of shit that will always have to be serviced by them.

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  9. Thank you for your very detailed, photographic depiction of "why your are SOOO screwed. Thank you for your support of GM, come again!"
    -It's $500 to have the dealer do this repair, for those that are curious. $190 for the part, the rest labor.

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    1. thank you so much...I found the part on amazon for under $100 ...but saved my money since the only one by me that can do the codes is the dealer...and has to be their part ...This truck has had more problems that I HAD to take it to the dealer for that any other... stupid computers that only the dealer can program!!!!

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  10. Why did my new gm fuel pump change wire harness and new pump doesnt have tank presure sensor but old one did,now i have po 452 code

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  11. Why did my new gm fuel pump change wire harness and new pump doesnt have tank presure sensor but old one did,now i have po 452 code

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  12. Thank you for your write up, I just replaced my fuel pump and did not fix my problem. read your write up, and bam water in my fuel pump control module, dried it out with a heater and cleaned it all up. Truck is fixed, I plan on sealing it up with some calk or gasket maker and hope for the best... Thanks again

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  13. I found this article after: 1) replacing fuel pump 2) replacing control module 3) need to haul truck to dealer for their "programming". Nice to know THEY were TOO big to fail.

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  14. I found this article after: 1) replacing fuel pump 2) replacing control module 3) need to haul truck to dealer for their "programming". Nice to know THEY were TOO big to fail.

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  15. I'm experiencing intermittent problems with the fpcm. 3 weeks ago truck died and failed to start,after running the codes I found this thread. Checked connections and the problem went away.3 weeks later problem happened again, I disconnected the harness and plugged back in. Now the truck is working fine. Anyone have this same problem?

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  16. What Im experiencing is the fuel pump wont shut off till the battery dies ,What the heck ? Flow module or pump assembly any clues

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  17. What Im experiencing is the fuel pump wont shut off till the battery dies ,What the heck ? Flow module or pump assembly any clues

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  18. Great article! To bad I'm reading about this now as my 2008 Silverado is being serviced and programmed for this problem right now :-(

    When I'm sick of dumping money into it just to keep it running(like my Blazer before this) I'm getting something with no/minimal electronics...VW Bug here I come(or an older truck).

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  19. Looks like they know about it. http://repairpal.com/recall/09V154000

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  20. do you know if the new autel scanner can reprogram the fuel pump control module

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  21. I had been thinking about buying a programming computer (j_box) for several years. This is the module that finally made me pull the trigger. Only cost me about $2000 so I could replace the module and program it. I used to like Chevy trucks. They were simple and cheap to fix. Those days are gone. Chevy sucks.

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  22. I am replacing my module now and am not sure how to unhook the wiring harness from the module. Can anyone help??

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  23. I'm also fighting that module. Can it be pulled and just replaced with a manual switch / relay to turn the pump on and off?

    I got my 2008 Silverado as a replacement for a 1989 Mazda B2200. That Mazda was a wimpy base model and wasn't very fun but the damn thing would not die (still going at 200kmi). The Silverado was like getting into a luxury car, I loved it. BUT the underside has an insane amount of rust for a vehicle of its age, has the typical stereo speaker problems, and always seems to throw codes and need various electronics fixed.

    I also have two Corvettes in the garage but think the Silverado has convinced me to buy foreign for the next purchase!

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  24. Im having similar problem, starts after a long period of wait, (over night) runs for 3 mins with 40-60 PSI fuel on the rails, then cuts out pretty quick.great information! helped me a lot!

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  25. Got code u0109 wiring for fuel pump control module. Going to check plug if it doesn't fix going to shoot truck not going to pay to have computer reset. Thanks for info.

    .

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  26. Going through the same issue here. Water has gone through the module and into my wire harness. (2007 new style) Two pins from the module have broken off and corroded into the harness. Option is a new complete harness...$$$$, get a donor pigtail from the wreckers and solder it on, or operate on the connector and try to recover what I have. And then.... install a new module and tow it to the dealership. Thanks GM!

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  30. PLEASE READ! Hey Brian, thanks man. I was laughing my ass off reading that. I hope you're sitting down because you're about to be really pissed off when I tell you this! I wanted to scream STOP, I CAN HELP YOU! BTW, you're gonna want to take that award and give it to yourself in a minute, ha. So you remember those machined bolts you THOUGHT were backwards? The're really not. If you look closer, you'll notice the end is hexagon. Why? That's where you put your 4mm. socket:) Simply turn each one about 10 cranks opposite or (CLOCKWISE) and did you happen to notice the holes were KEYHOLED? Simply slide it over a 1/2 inch and it's out! Aside from the tire, you could've had it in and out in about 5 minutes! Yeah man, you never needed to take that winch bracket out and all that shit! You did a good job illustrating and describing everything for others to check out but, you might want to update my instructions to your blog. You could probably save a lot of people some frustration and headache if, they're lucky enough to read it BEFORE doing it! lol... Anyway, I got mine in and, i'm gonna attempt to program it tomorrow. Can you hit me up before I do it? 913-207-2902 i'd appreciate it. Take care, Shane Kansas City

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  31. No, I think i'm gonna want that award! Now that I have it in and no no program! I guess i'm gonna have to start calling some mechanic buddies to see who has access to a programmer then, talk them into bringin' it over. What a crock of shit! If i take it back out and have the VIN could I take it in? BTW, another side note. I have 2010 Avalanche. The module location on Avalanches, Tahoes, suburban's etc. is actually pretty easy to get to. It's under the driver side, on the cross member between the trannie and frame. Wish me luck!

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  32. Brian, I am not sure if anyone has mentioned this, but the connector for the FSCM extends into the FSCM slot when the latch is closed. While working the latch to clean the crud out of the connector, the internal mechanics of the connector gave up and now I have a communications error code from a FSCM request malfunction code..... aaarrrrrgggghh!!!!

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  33. This just ended up costing me $2000 on a 2008 GMC Sierra. I live on an island in Alaska so it was a couple of tows and a barge ride to a dealer. Ridiculous. My next vehicle won't be a GM.

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  34. I love this. So much fun. Thank you for the write up, it was helpful and amusing. I sometimes wonder why shops don't have the correct equipment to do the job.

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  35. yeah taking this module out took a whole of 3 minutes. complaining about taking it out when all you need to do is put inverted torx on the end and turn it right to un do it a little bit and slide it over. not hard at all. you need the jackass award for being uneducated about it and complaining about it lol

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  36. Did you guys have no power at the module also? I am having same problem of no power at the pump. which wires do i check at the module and are there any fuses ahead of this.. I like how the fuse box is misleading

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  37. check out this link ! GM recall notice ! https://www-odi.nhtsa.dot.gov/acms/cs/jaxrs/download/doc/UCM472842/RCRIT-14V614-0055.pdf

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    1. this is not an actual recall...just a notice for a potential recall.

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  38. First, thank you for posting all this info on how to fix the Fuel Pump Control Module, and potential recall info. We too just experienced a failure of the FPCM in our 2009 Chevy Silverado 1500 Ext. cab. However, just because there is a 'recall bulletin' issued, that does not necessarily mean that an 'actual recall' has been issued for the vehicle or problem. According to our GM dealership, it only gives instructions to the servicers (part #, replacement instructions, etc.) if one should need to have it repaired. The dealership will look your vehicle up by VIN # and tell you if a recall had been issued for it. This was a good website overall though...very helpful. Thank you.

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    1. go to my.gm.com/recalls and put in your VIN # to see if there is an actual recall on your vehicle. If not, you can get your vehicle registered by calling the phone number on page 9 of the bulletin
      https://www-odi.nhtsa.dot.gov/acms/cs/jaxrs/download/doc/UCM472842/RCRIT-14V614-0055.pdf

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    2. Upon further investigation (and several calls to GM), we found that there had been a recall for the year, make and model of our vehicle, however, recalls are VIN specific and due to where it was manufactured (Canada), our particular vehicle was not included in that recall. In order to get included in a recall, one must register a complaint about the problem. If enough people register complaints, then there may be another recall issued in the future, and the possibility of reimbursement. In order to qualify for a future reimbursement (assuming a new recall is issued), we must pay out of pocket for the repairs at an authorized GM / Chevy dealership. Argh!

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  39. I had the same problem but I was told it was the fuel pump. So I changed that and it wasn't it. Changed the fpcm and got it programmed and I still get codes P2635 and P069E can anyone help? The truck runs normal it seems butwhy is the engine light coming on and giving these codes?

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  40. Excellent post, thanks for sharing..! Salvage cars

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