Dunqan

Hi all,

This is on a 2013 Cayenne, base model with a manual transmission (love the manual!), currently in CA, but formerly in MA - approx 54k miles on the vehicle.

I have a problem that the Porsche dealership in here Orange County was unable to track down (frankly I was disappointed with their lack of taking this issue seriously but that's another story). So I thought I'd see if I could leverage the genius mind of Rennlist to see if there was hope for a fix.

The problem is as follows: when it's hot outside (85 degress F or higher) and at low RPM (stopped at a light for example), everything will seem fine but when the accelerator is pushed there is little to no response from the engine and faults will start to pop up on the display. Other electrical components such as the windows will also fail to respond. This happens very intermittently, like once every couple of weeks, although can also happen twice in a day on occasion. But it has been progressively getting more frequent during hot weather.

Two Summers ago, one time, our Cayenne showed a bunch of faults and wouldn't respond until shutdown and restarted - my wife was driving so I heard it 2nd hand.

This past Summer - during hot weather our Cayenne had the problem multiple times. It would flash several errors on the panel like "Brake Fault Distribution", "Chassis system fault", "Fault headlight control", "Fault Generator" and possibly a few others.

Researching these forums suggested it was a low voltage issue that is sometimes attributed to shutdowns and lots of error messages caused by a degraded battery. I had the battery changed out but unfortunately that didn't solve the problem.

Here is what I know:
The Cayenne appears to be experiencing low voltage issues or some sort of electrical issue which is causing
It only happens during hot weather (85 degrees or higher I'd estimate) and higher temperatures seem to cause it to happen more often.
Only happens at low RPM - never had a problem while driving, only after stopping at a light and then attempting to accelerate, or starting the car in a parking lot and reversing and stopping to change directions.
It can happen after the car has been on for 20 seconds or 30 minutes.
Very hard to replicate unfortunately even when trying to stall the engine and such the car will run just fine, then all of a sudden it'll hit again 2 days later for now apparent reason.

My guess is that there is a loose or corroded connector somewhere but I'm no expert here unfortunately.

The dealership did a check and wasn't able to find anything, they said they opened the main computer and checked to see if there was a leak/corrosion but didn't see anything.

What else should I ask them to check? Any common areas of issue that cause this type of issue?

I'm going to attach a video showing it happening once for a clearer indication of what exactly is happening.

I also had a Samsara unit attached during a trip and captured several readings of RPM and voltage - listed below - I'm surprised there is so much of a difference. This was before I had the battery replaced so I'm not sure if I would get similar indications today, but since that didn't fix the issue I think it might be similar:

2:35 pm 766 RPM - Battery Voltage - 13.83 Volts
2:38 pm 1,869 RPM - Battery Voltage - 12.44 Volts
2:40 pm 2,037 RPM - Battery Voltage - 14.13 Volts
3:13 pm 653 RPM - Battery Voltage - 13.45 Volts
3:16pm 642 RPM - Battery Voltage - 15.53 Volts



Thanks for reading this and really appreciate any ideas/help!

Brian

schernov

Did the dealer pull any codes with PIWIS ?
ask to see those.

was the battery registered when it was replaced? If not, do that. Although some say it's not needed.

this could seem like a bad ground somewhere. Check for water in all the usual places to make sure you don't have a short in body modules. Foot wells. Rear spare tire compartment. Check that the battery ground is not loose. Maybe it is moving as you start off.

Dunqan

Yes the battery was registered - double-checked on that.

The dealer said they were able to pull the old codes, but weren't able to replicate the problem (which wasn't a surprise since I told them it was very intermittent).

Yes a bad ground is certainly a possibility from what I've read - just not sure how complicated that is to track down. Thanks for the pointers - I'll check those spots although I doubt it'll be water due to the fact that the car has been in CA for 3 years now with very limited rain/water exposure. But I'll definitely take a look.

Would they notice a bad battery ground when they replaced the battery? The battery was replaced and had the same behavior before and after - I would imagine properly connected when they replaced it but I didn't do it myself so I can't be 100% sure.

Thanks!

schernov

I am surprised they did not use PIWIS for fault finding. It should be able to identify bad connection.

Drive with sport button (not sport PASM) on for a while. That forces voltage to be higher all the time. See if problem persists. If it goes away - that would rule out bad ground issue.

if you had dealer replace the battery - it should have 2 year warranty. Go to another dealer and complain about not start and ask them to put a new battery under warranty.

Dunqan

Thanks for the info - I'll try the sport button to see if that makes any changes.

I wasn't very happy with the dealership's lack of taking the issue serious (Irvine, CA) - so my questions here are to arm myself to go to another dealership (Newport Beach, CA) to see if they're able to diagnose and fix the problem better. I'll be sure to as for the PIWIS output from them when I take it in there.

Brian

garrett376

Check engine light occur also? Then you should replace the coils.

Rocknroad

Be aware that both Irvine and Newport are under the same ownership. I'm sure the Service Manager can be the difference in attitudes but, the lack of attention to the customer might come from the top. I know it's a haul but, I hear good things about Walter's/Riverside Porsche. If all else fails, DM me for the name of my Independent (in Irvine).

I have an appointment, at Irvine, two weeks from now to check out my hinky transfer case. Here's hoping they just do it right the first time.

MBDiagMan

It’s definitely a power supply issue of some description. The most common problem in that area is a loose or corroded ground connection.

It is important that you fix this to keep one of our precious manual gearbox cars on the road.

MBDiagMan

This is a power supply issue of some description. Find and clean ground connections to start with.

reneeweiss

Since you said the car came from Ma. I bet there is some corrosion somewhere in the electrical system from the salt used on the highways to melt snow and ice. What about the alternator itself has that been checked to see if it puts out the requirements across the board, it could be the voltage regulator that I believe is part of the alternator these days. I thought that the battery is mainly used to start the car and run electronics or lights prior to the engine running. You should also check the voltage when the car is first parked after running and then the next day to see if it is holding a charge or draining because of a short or something left on. You could have a bad battery even if new and you could have a bad alternator since it seems to have been happening prior to getting the new battery. I don't find the dealers very responsive in general. I use one a hundred miles away that has been a family business since the 1900's and a Porsche dealer since 1956.

Dunqan

Thank you all for the extra answers - I want to make sure I have as much information as possible before going to the dealership to make sure they have a thorough inspection to try and find the problem.

It definitely seems like it might be a ground issue, unfortunately it's unclear to me how hard that might be to track down.

The alternator has not been directly checked as far as I know or at least they didn't mention it specifically - although I would assume it would have been given that it seemed to be a voltage issue (the dealership never directly mentioned they had checked it and I unfortunately assumed that would be one of their first checks so when they talked about other checks they did I didn't pursue it).

I'm definitely open to going to a quality independent - I just thought that the dealership would have the best chance of finding what would seem to be a somewhat onerous problem (best dianostic tools, potentially most experience and/or references for similar issues).

Thanks again!

Brian