P0004 - 987.2

Hi All - I had my new to me 987.2 CS for just under 1k miles (funny just within the limited warranty), and got this code. My local Indy shop (know them personally), checked it out, tested the single too/from fuel pump , diagnosed all they could and came back with nothing that made sense. Fast forward ~3months, trip up to ToD, plenty of "spirited driving" code hadn't come back, till last Sunday, drove the car with my fiance to brunch, CEL came on, came back scanned the car, P0004 (max threshold exceeded) or something like that, can't remember exactly what durametric said. Car had 3/4 tank of fuel, runs totally fine....I am not a fan of throwing parts at cars....wondering if anyone has had any experience? I need to get the car up on the lift and see if i can get to the fuel pump plug , hoping maybe there is a loose or corroded connection. In the meantime, any feedback is appreciated!

Which engine do you have? 2.9 or 3.4 (S)? The fuel injection systems on them are completely different (different manufacturers even..) It appears to be fuel-related, but without knowing which engine - it would just be speculation. The 3.4L uses direct injection with a high-pressure-fuel-pump with regulators on the pump. the 2.9L uses port-injection with a "normal" pressure fuel pump, with a regulator built into the pump assembly I believe.

Sorry should have added that, its 3.4L, CS.

I have seen a few posts across the forums with issues on the HPFP on the DFI motors... not to the point of saying there's a design flaw, but it's more than the failure rate on standard injection systems. You may want to get a deeper diagnosis with a Porsche -specific scanner to see what's going on. You may want to look at threads about the HPFP as well, as there are a few across different models, from what I've seen recently.

I've scanned with my durametric cable, it doesnt give much more detail. I've dug around and there doesn't seem to be an overwhelming consensus on failure rate, there is a thread if found somewhere about certain vins that failed, again no consensus about specific build dates etc, and most of this was all from many years ago...there is more info on the 997 cars having issues, not as much on the 987

I didn't expect a straight code... I meant that you might have to read values and troubleshoot more deeply with these tools. A code would be nice, but without that you'd have to dig into the data and see what's tripping it up. Basically, use the reader to check the pressures and compare them to spec (sorry, I don't know what the "correct" should be, but I'm guessing that's why it's tripping up...)

Understood, the indy shop it went too initially did that, they couldn't link it to anything unfortunately. The worst part is that the CEL with go back out after so many miles of it working properly, which certainly has me leaning towards a wiring issue. Going to up the lower panel off and check the connect in the morning and see how the connection looks.

Well, overdue and unfortunately non-ground breaking update.... Haven't really had much time at all to drive the car, I believe since my last update, we took the car to cars & coffee, no CEL, YaY....then took it to some friends house for a cookout, drove all the way there, then on the way home CEL....womp womp....scanned, and of course P0004 (value too high).... Pulled the lower belly pan, removed the connector, inspected, no corrosion, still cleaned with electrical cleaner, filled the plug with di-electric grease.....took the car the dentist, then lunch, maybe a 15mile drive, left lunch and on the way home CEL....again....P0004 Plan is to run a can of seafoam through the fuel system, if the issue persists, I am due for some maintenance, so I may send the injectors out to get cleaned while doing new plugs and coils. Also noteworthy, car runs fine, nothing seems at all out of the ordinary....

I doubt if cleaning injectors will do much other than empty your wallet some more. The "common" fuel failure on DI cars is the high-pressure fuel pump . So far what I'm seeing would lead me to research that a bit more, and perhaps find a more capable scanner than a Durametric, at least one with Porsche specific code descriptions. EDIT: FWIW - I doubt if the high-pressure injectors can be cleaned. If you find a service that offers this - please let us know. These direct-injectors are completely different electrically and hydraulically from the old style low-pressure injectors used on port-injection systems.

I don't disagree that its a long shot on the injectors but the car has ~75k miles, my thought was, it couldnt hurt. I'll have to circle back with my buddy that own the indy shop, I believe they have scan tools other than durametric (although I know they use durametric for a lot) re: injector cleaning, googling quick i found this place: GDI Gasoline Direct Injectors - Clean, Test, and Match - Injector Experts Appreciate the feedback, I know I'll get to the bottom of this...just hoping it doesnt involve buying a ~$1200 HPFP

I've posted a reference chart for Porsche codes (and generic OBDII codes) at Diagnostics: - OBDII and Porsche Specific Codes, 987... That code is rather specific, and so far our experience here is - I've never seen anyone report a bad or failed injector. I have seen people need to replace the HPFP due to pressure issues. The "rebuilt" ones sold on places like eBay rarely seem to actually work. So the real answer IMHO is a new one from Porsche (or a supplier who provides Porsche OE parts at a discount.) BTW - see you asked the same over on ******** and got a total lack of replies. Not a surprise, all the good people moved over here (see the link in my SIG for the reason why..) Good luck and let us know how it works out..

Yeah, I went down a rabbit hole on here about different VINs that had the pump recalled/replaced, but could never get a real "good feeling" about where my car fell b/c the list didn't necessarily seem seem to have definitive VIN ranges for years. I wouldnt buy a rebuilt pump for sure, looks like you can get new ones from FCP euro for <$1200 ( Porsche Direct Injection High Pressure Fuel Pump - Genuine Porsche 9A111031506 ) this might have to be a winter project at this point....wedding in october and current home remodeling project is keeping funds directed elsewhere lol I did post on ********, was certainly bummed with the lack of reply....also, I read the link in your sig, rather curious, I had not clue!

Not that I was expecting anything ground breaking....BUT....dumped a can of seafoam in the tank this morning with ~1/2 tank of fuel, went and topped it up with fresh 93oct. Drove to get my hair cut, put exactly 21 miles on the car getting there taking the long way, no CEL, YaY!....then came out from getting my my hair cut, got in the car, no more than drove off and CEL came on. I will say, as I started the car after filling up at the gas station, it did bumble and not start right away. That is the first time that h as ever happened.....going to keep a close eye on it, see if my buddy that owns the indy shop could come ride along and do some data logging/monitoring....but looks like I am going to need to replace the HPFP

For what its worth, my CS had a bad HPFP when I purchased it in 2013. The engine was substantially louder / rougher sounding than normal, but I do not recall seeing a CEL. Selling dealer replaced the pump and no issues since then. Good luck with figuring out your issue.

Thanks for the info!

Keeping this up to date for records.... Had a mountain drive planned with some buddies I haven't driven with since being up at ToD in April, so used that as reason to change oil and spark plugs , to get on a known maintenance regiment. While in there, cleared codes, "tried" to reset the service light....then set out on my drive. After the ~45min of cruise up to the meeting point, no CEL, great! Shut the car off, chat with the guys, get in the car, drive rather spiritedly for ~35miles, stop at an overlook on the parkway, chill for 30min, back in the car, back down the same route, to the meeting point...no CEL, keep thinking, maybe new plugs cleaned up something odd the ECU was detecting....get back to the beginning meeting point, stop, chat....leave 20min later, within 500ft of starting the car.....CEL comes ON.....F-ME! Then decided to take the car to lunch sunday with the misses, during one of the start/stops, turn the car on, no more CEL, then a little later it comes back on. Still has me very curious if it could be wiring, but continuing to drive towards the pump is on its way out...

Thanks @fouckhest for the update. Please keep us in the loop on your path to discovery. My car has had a random P0004 that will pop its head occasionally on my durometric, but never had a CE, yet... My car also never felt it has had any issues. Unfortunately there is not a lot of information out there currently to diagnose the issue.

@fouckhest , did you end up finding the rootcause? I have a similar issue as well! thanks