Cayenne PCM Issues - My solution
#1
11-11-2017, 03:04 PM
Cayenne PCM Issues - My solution
For what its worth, I wanted to chime in to write down, what I observed during troubleshooting of PCM issues on my CTT.
Over the last year, I observed the following issues:
- PCM resetting
- PCM getting very hot
- PCM turning off on its own
- Maps not loading
- Maps freezing
- Cannot change stations
- Cannot change volume (turning know results in no changes)
- Cannot hear any sound
- PCM reset when accelerating
- various manifestations of all of above.
The issues started slowly, but over time they accelerated until the point where PCM was not working at all. When driving it would start resetting and I eventually disconnected to ahead of troubleshooting.
Tried many different things, including taking the PCM apart to debug the boards. Nothing was found out of the ordinary there.
To make a very long story short, I started looking at the antenna and satellite connections at the back of the PCM. I noticed that the plastic on the ends which plug into the PCM, were wearing out and started flaking off. One of the connectors was worn down to the point where it was obvious to me, that it would not hold in place when attached.
Decided to remove the plastic connectors, and use zip ties attached to each connection cable, to affix these connections to the back of the PCM, using small slots in the chassis to place zip ties through and keep each connector in place very securely. Essentially, I ensured that each connector was unable to move when attached to the PCM.
Once I made the connections secure, started the car.
Removed fuses for the radio on passenger side of the car (small black access panel once door is open, then pulled fuses 9, 10, 11, 12).
Waited few seconds. Then plugged fuses back in one by one - 9, 10, 11, 12.
When I did that, noticed that the PCM is no longer resetting, and is working perfectly.
My fix is attributed to bad/work plastic connections for antenna and sat.
They interfere with the programming of PCM and radio/sat functions, causing the FW to crash due to intermittent connections. I tested it once and crashing started to re appear when I had connections just sitting attached witout zip ties. Then once I put zip ties back in, reset fuses again, crashing stopped.
So if you are experiencing these issues, I would urge you to inspect and replace the sat/radio antenna connections. Worked for me 100%. Hope this can help others here.
Over the last year, I observed the following issues:
- PCM resetting
- PCM getting very hot
- PCM turning off on its own
- Maps not loading
- Maps freezing
- Cannot change stations
- Cannot change volume (turning know results in no changes)
- Cannot hear any sound
- PCM reset when accelerating
- various manifestations of all of above.
The issues started slowly, but over time they accelerated until the point where PCM was not working at all. When driving it would start resetting and I eventually disconnected to ahead of troubleshooting.
Tried many different things, including taking the PCM apart to debug the boards. Nothing was found out of the ordinary there.
To make a very long story short, I started looking at the antenna and satellite connections at the back of the PCM. I noticed that the plastic on the ends which plug into the PCM, were wearing out and started flaking off. One of the connectors was worn down to the point where it was obvious to me, that it would not hold in place when attached.
Decided to remove the plastic connectors, and use zip ties attached to each connection cable, to affix these connections to the back of the PCM, using small slots in the chassis to place zip ties through and keep each connector in place very securely. Essentially, I ensured that each connector was unable to move when attached to the PCM.
Once I made the connections secure, started the car.
Removed fuses for the radio on passenger side of the car (small black access panel once door is open, then pulled fuses 9, 10, 11, 12).
Waited few seconds. Then plugged fuses back in one by one - 9, 10, 11, 12.
When I did that, noticed that the PCM is no longer resetting, and is working perfectly.
My fix is attributed to bad/work plastic connections for antenna and sat.
They interfere with the programming of PCM and radio/sat functions, causing the FW to crash due to intermittent connections. I tested it once and crashing started to re appear when I had connections just sitting attached witout zip ties. Then once I put zip ties back in, reset fuses again, crashing stopped.
So if you are experiencing these issues, I would urge you to inspect and replace the sat/radio antenna connections. Worked for me 100%. Hope this can help others here.
#2
02-09-2018, 06:15 PM
Experiencing Similar Issues
I’m experiencing the same issues. How did you access the antenna connections that you connected with zip ties? I tried just pulling the PCM fuse (only one fuse on my 2014) for a few seconds to see if that would resolve the issue but it didn’t. Willing to try what has worked for others before replacing the entire unit out of pocket. Thanks in advance!!
#3
02-09-2018, 08:32 PM
Had to pull the pcm out. Then zip tied to mske sure connections are solid, then pulled the fuses. After that, no more resets. I think the firmware queries pcm for signal and if it disappears firmware gets hung and pcm reboots.
hooe this helps you too.
hooe this helps you too.
#4
04-26-2019, 07:01 AM
Porsche Cayenne E3 (2018) PCM issues
I have had all of the symptoms you describe above with my new Cayenne E3 (June 2018). This photo is the latest gimmick: the screen suddenly turned blood red and so bright that i struggled to see the road
#5
04-26-2019, 07:53 AM
I would try to find out if there is a reset sequence for your PCM. Looks like the processor somehow lit up all the segments of the panel and keeps them on.
In my Cayenne, i can press the numbers 1, 3, 8 simultaneously, resulting in a PCM reset. Not sure what that sequence is for yours, but would be good to find out (call dealer??), so you can reset PCM and see if the display is fixed.
If you do not know the sequence, another trick is to remove battery cable (unscrew the neg teminal and remove from battery for about 20 minutes). Then, put terminal back in and see if the PCM reset itself.
Hope this helps.
In my Cayenne, i can press the numbers 1, 3, 8 simultaneously, resulting in a PCM reset. Not sure what that sequence is for yours, but would be good to find out (call dealer??), so you can reset PCM and see if the display is fixed.
If you do not know the sequence, another trick is to remove battery cable (unscrew the neg teminal and remove from battery for about 20 minutes). Then, put terminal back in and see if the PCM reset itself.
Hope this helps.