grubscrew

Hi, I hope someone can help me fix my pig, I have, had issues with it for a while now but it's gradually getting worse, upon getting in the car and turning the ignition the starter will only turn for a second or two before cutting out, essentially before it starts, this will continue until the battery dies, sometimes after a couple of tries it will start no problem other times take 6-10 turns of the key before it starts, when it does eventually start sometimes it runs fine and sometimes its a bag of hammers with no power, I recently had fault codes for crankshaft position sensor and camshaft sensor, these were replaced but still get engine warning light, it has recently had new battery and starter motor and had no issues after that, I now have so many fault codes I don't know where to start, one of the codes is high pressure fuel pressure low which is making me think the high pressure fuel pump is bad causing the ecu to stop the engine turning over until the pressure is up, I could be totally wrong but would gladly take any advice to point me in the right direction. Thank you

Petza914

Boy, usually when you see multiple seemingly unrelated codes, it's a battery or voltage issue. Maybe you have a bad wire to the starter or the battery and although the battery is fine, it's looking like a low battery condition. Since you bring up the HPFP, I'm assuming you have a 957 generation Cayenne - always helps with tech questions if we know the year and model. If it's a 957, try to open the power hatch 3 times in a row with the car not running and see if the hatchback stalls part of the way up any of those times. That's a really good indicator of a weak battery or maybe something voltage related. I think a HPFP issue would give you that specific message and the car would also not run right, but maybe it's just starting to go and that's why sometimes it runs right and sometimes it doesn't.

The other thing to check is whether there has been any water under the carpets that will corrode the splices in the main wiring bundles. You have to lift the carpets, then lift the thick foam to check under the foam on the front driver's side and passenger side.

dr914

sounds like you need a starter. The cayenne starter fails in mysterious ways, sometimes you engage the key and nothing happens and then all of a sudden it turns over. Not an easy job to replace but it will come out easier than the manuals say it will

grubscrew

Thank you for the reply, yes it is a 957, 2008 S, I am finding it hard to believe its the battery or the starter as in the 5 years I've had it it has had 6 batteries, the latest only 6 months ago, it charges fine and holds charge until I come to start it, I also had the starter changed by my closest porsche dealership and this was probably less than 10000 miles ago, I think I may have to bite the bullet and get both again, something I did not want to do but it's driving me crazy and even though it runs great when it feels like it I am seriously considering breaking it for spares, my closest dealership is 200 miles away and to get it there is a nightmare
​​​It really seems like the ecu is stopping it from turning but I just can't seem to pinpoint it with so many error codes. It may be my imagination but it sometimes seems to start better when turning the steering wheel while turning the ignition, but as I say that could be me imagining it lol

grubscrew

Sorry I forgot to mention I have no power tailgate and under the carpets are dry as a bone

brett968

You might want to check the main engine ground cable. It's located on the right side of the engine up front near the alternator. It terminates on the frame rail.

cayenne20007

Hi
I am in similar situation, same car (2007/8 s) and the car was running fine but starting the engine was a nightmare, battery depleted very quickly and only if I had charged the battery overnight did it start okay but if you went to get some petrol often struggled to start the engine and it usually took 2-3 attempts with 5 mins wait in between. Not good

Yesterday I replaced the starter motor and it starts beautifully now, so all good on that front but the CEL has now come on, the car drives perfectly, no lag, accelerates fine, and more importantly starts at the first attempt every time without depleting the battery.

Read the codes with Torque pro and tons of errors but the 2 main ones are
P1023
P0331 Knock Sensor 2 Circuit Range/Performance (Bank 2)

I think the P0331 is something I must have done when I replaced the starter motor, if it is the one right underneath the starter motor I must have damaged it (there was also a lot of dirt/grease in that area which I cleaned out.

But the 1023 code baffles me, i checked fuel rail pressure with the torque app while driving and it seems to be fine, responding well to acceleration etc. I did not touch the HPFP apart from undoing the fuel rail but I triple checked all connections when putting it back in and also cannot smell any fuel in the engine bay.

I am waiting on a better code reader as I am not sure if the torque app is capable of erasing the fault codes properly.

There are also error codes but will double check them with the new code reader over the weekend

Did you manage to resolve your issue?

grubscrew

I have not had a chance to have a look at it yet as I have been away with work, hopefully this week I will take a look, think I will start with new starter just to elimate it

bzowk

What was the resolution to your P1023 code? Replaced starter in my 2008 S yesterday and am getting it. Did it go away on its own? Thanks!

Petza914

You guys probably unplugged the plug from the knock sensor on top of the motor and forgot to reattach it during reassembly. It's just an2 wire plug that clips into the disc looking thing.

bzowk

Thanks for reply, but I personally am not getting a knock sensor code - just the P1023. Was just wondering (hoping) it's one that will go away on it's own after a few cycles perhaps. Just read fuel pressure at idle on cold engine stays around 550-600 bar. Seems to have a smooth idle without backfires and no fuel smell so was hoping good to go.

Thanks

cayenne20007

luckily it did but I also had a misfire on cylinder 6 which I fixed by replacing the fuel injector cleared all the codes and no more (persistent) errors since

bzowk

great - thanks for the info. Haven't detected any misfires yet, so hopefully mine will clear, too. Drove a little yesterday and orange exclamation on dashboard (what great detail that gives) went away after a bit but code still resides. Guess I'll wait and see.

Thanks for taking the time to reply.

Petza914

The orange exclamation remains after a more specific message is displayed as a reminder. You can access the message with the buttons on the stalk. The owners manual should cover this.