sac02

This happened last night on the drive home, and again this morning on the drive to work. Vehicle in question is a 12MY TurboS with 126k miles.

Vehicle starts and drives fine (default to comfort/standard PSM mode). When put in Sport, the following happens:

• "Sport Mode unavailable" message in combimeter
• "Fault Transmission" message in combimeter
• "PSM Fault" message in combimeter
• Traction control / PSM indicator Icon illuminated
• Check engine light NOT illuminated
• Vehicle goes into limp mode (low rpm shifts, very slow shifts)
• When placed in Park, "Auto Start/Stop unavailable" message in combimeter

Last night I limped home. When at home, I turned vehicle off, then back on - the error messages in combimeter were gone, the vehicle drove normally around the block in comfort mode (I did not try to engage Sport)

I then checked DTC with PIWIS. I recorded them and then cleared. They did not come back during the time that I sat stationary in the garage and started/stopped the engine a few times.

Today I was driving to work and brought PIWIS laptop with me. When I selected PSM Sport mode (after 20min of driving in Comfort), IMMEDIATELY the same situation happened. I pulled over and read codes immediately while vehicle was still running.

These codes I gathered this morning are consistent with the ones I had last night.

Gateway
C12097 - active - Check A/C unit fault memory content
DME
P0355 - inactive - Bar ignition module, cylinder 5 (no signal/communication)
P1583 - active - sport mode not available (below limit)
P2314 - inactive - Bar ignition module on cyl 5 - soft shutdown (limit exceeded)
Transmission
U0401 - inactive - Check engine control unit fault memory content (No fault symptoms)
U0418 - inactive - Check PSM control unif fault memory content (No fault symptoms)
U0456 - active - Check air conditioner operator control circuit - this fault can be ignored if active (no fault symptom)
Adaptive Cruise Control
C12085 - inactive - Data bus - fault value received from braking electronics control unit (PSM)
D00007 - inactive - Function lock active
PDCC
C12085 - active - Check PSM control unit fault memory content
PSM
002087 - active - sport mode, transmission, faulty
00208A - active - sport mode, faulty
C12080 - inactive - check engine control unit fault memory
C120A1 - inactive - control unit fault, center diff. lock

My thoughts:

1. This symptom set does NOT seem to be the same as a common issue where the vehicle will throw errors, and then not go into gear after coming to a stop. Both times I've never lost gear engagement at any point, in motion or at a stop.
   1. The "sometimes won't go into gear / seems like it's in neutral" often has people pointing fingers at transmission solenoids, switches, and valve body parts.
2. I think the messages about A/C circuits are byproducts, I do not plan to follow them as a suspected root cause.
3. Does the word "bar" in P0355 and P2314 actually mean "bad"? (typo in PIWIS/DME software?) If not a typo, what does "bar" mean in this context?
4. I'm unsure if the PSM or the DME is setting the first code.
   1. It's curious that this morning it happened IMMEDIATELY when I pushed the sport mode button.
   2. BUT: I find it curious that specific codes for cylinder 5 coil are being set - that seems oddly specific
   3. So Maybe: Is a bad coil setting a DME code (which then cascades)?
   4. BUT: If the root cause was a bad coil and DME DTC, that SHOULD set a check engine light, which I don't have happening.
   5. So Maybe: I'm wondering if the DME codes for cylinder 5 are only byproducts of DME Limp Mode logic - maybe Cylinder 5 just happens to be the cylinder that was chosen for ignition cut logic whenever the Limp Mode is triggered?
5. I found a thread on 6speedonline of identical symptoms and codes (I feel strongly it's the same issue), and several people over the years saying "me too". Unfortunately OP or other commenters never updated with details regarding their resolution. One commenter further down said something brief and cryptic like "I replaced coils OK"
6. I found a thread (can't remember where) that had similar symptoms and the issue was reported to be traced to bad connections in the air suspension system (think loose connector at a shock) causing the PSM to freak out.
7. Another thread with similar but not exact symptoms was found to be the rear height sensor at fault.

My Plans:

1. On the drive home today, try to select Sport Plus - see if same thing happens. If not, engage Sport and see if/when it happens.
2. At home tonight: swap coils between cylinder 5 and maybe cylinder 1. See if DME coil faults follow the coil to cylinder 1, or if the DME faults stay on cylinder 5.
3. Today I ordered 8 new coils and plugs, it's probably time to refresh them anyways.
4. I plan to check under the vehicle to make sure some road debris didn't jump up and damage a wire harness under the vehicle or something, but at the moment my lift is not working because one of the cylinders sprung a leak and is getting re-sealed.
5. Probably due for a PDK transmission oil change, I have fluid and when my lift is back in service I will do that.

Does anyone have any thoughts or comments?

If you have experienced the same, or recall a thread about this issue, please link me to it, especially if it seems to contain the root cause.

If you have diagnostic thoughts on what else I should investigate, please let me know. One thing I'm trying to figure out is how to isolate if it is a DME DTC that is then cascading to the PSM, or the other way around.

vkb123

I’ve never experienced this but I have read threads in the past describing very similar issues to what you are describing. Usually over 100K miles. From what I recall, usually ends up being coil related. Please keep us posted.

sac02

Update 2/15 PM: 25mile commute with no abnormal behavior. Switched into /out of Sport and Sport Plus several times. So maybe don't put a lot of weight on the fact that this morning it happened Immediately (and it was immediate) upon pushing the Sport button?

I will update as available.

Part of the reason I posted such detail is to try and help others in the future by seeding lots of search terms and DTCs. Because although I came across several threads asking for help with this type of issue, not a single person was good enough to come back and close the loop to tell what the resolution to their issue was. I hate when people do that, it really bugs me that people expect the forum to answer their questions and solve their issues, but then they walk away and don't contribute to the knowledge base.

Sorry. End rant

Marcus13190

Yes it's coil problem or battery problem when you have lot of fault codes.
But i think that you need to change coil on number 5 cylinder (P0355 - inactive - Bar ignition module, cylinder 5 (no signal/communication))

sac02

I'm pretty confident it is almost certainly not a battery issue because:

​​​​​​* battery issue would likely include a few DTCs regarding voltages. (these could be for ecus not involved with he fault, like there would be a random history DTC in the combimeter for voltage below threshold)
* battery issue would likely include a few DTCs about missing messages or lost communication between ECUs. (communication codes generally prefix with "U" in the DTC)
* battery issue would likely present near start-up, not after 20min driving.

Marcus13190

Ok youy are the best !

sac02

Update 2/16 AM:

I did NOT change coils between cylinders 1 and 5 last night as planned. Poop happened at work and I had to stay late and I was just too tired. I tried to do it in 10min this morning but I didn't have a stubby T30 torx to take out the bolt holding on the trim cover over cylinder 8.

Today on the way to work I got "PSM failure" and similar DTCs 24minutes into my commute. Interestingly I did NOT get "Fault Transmission" message, and the vehicle did NOT go into limp mode. The instant that the warning happened was the moment that I squeezed the throttle a little harder/more aggressively than average.

This makes me wonder:

• Perhaps the trigger for the fault is quick throttle / RPM changes.
  • Occurrence 1: Don't remember exact conditions at the instant of occurrence
  • Occurrence 2: Happened when switching from Comfort to Sport, which almost always results in transmission downshift a gear
  • Occurrence 3: Happened at moment of high throttle rate of change - and possible pending / attempted downshift?

Next steps:

• Hopefully leave work early today lol
• buy and cut down an L-key to make a stubby T30
• Swap ign coils between #1 and #5, then go test drive (today, friday)
• drink beer
• New coils hopefully arrive this weekend, but hopefully swapping parts between cylinders will give me some good info prior to new parts arriving

leedo3

I had a similar experience where a bunch of fault lights came on.
Resolution was to replace a bad coil.
Seems like that coil fault triggered other unrelated faults.
Hope your solution is that simple.

BTW: bar is a European measurement of pressure, analogous to U.S. "psi"

sac02

Thanks for the input. I've got my fingers and toes crossed that the new coils that are on their way to me, will hopefully be the root cause.

I am familiar with the pressure unit "bar" but it does not make sense in the context of an ignition system / ignition coil DTC.

leedo3

Sorry for the confusion.
Bar Ignition Module is the Porsche technical description of the Coil Pack

sac02

Significant update:

Last night I swapped coil packs on cylinders 5 and 1.

This morning (2/17) symptoms reoccurred. Checked DTCs with PIWIS - this time P0351, Bar ignition module, cyl 1 and P2302, Bar ignition module on cyl 1 - soft shutdown.

To me this is strong evidence that the fault is following the coil pack.

New set of 8 coil packs scheduled to arrive tomorrow.

sac02

Annoying non-update lol: I drove about 90 minutes / 60 miles this afternoon/evening and no errors. Suspect coil pack is still on cylinder 1. Was really hoping it would give me the error at least once more on cylinder 1 before I get new parts tomorrow.

Maybe I'll just leave the suspect coil pack in place for a little while longer to get another error on cylinder 1, before I install new parts. That would take me from 95% confident to 99+%.

Of note: When I was swapping coil packs from 5 to 1, I first removed the suspect coil pack from cylinder 5. It had a nice crack in it (see Pic) and I immediately thought, "Well THAT'S a smoking gun..."

Then I removed the coil pack from cyl 1 and it had the exact same crack lol.

So who knows. Maybe they are all bad and cyl 5 just was the worst and all the others are going to **** the bed tomorrow. :shrug:

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cboxell

My first failed coil pack wouldn’t happen until it got hot and heat soaked, then would fault out with the codes you have. Just change the coils when they come in, because that’s probably not the only cracked one you’ll find.

vkb123

When were the coils last replaced (time and/or mileage)?

rnlst_log

Obvious sign of bad coil pack.
Replace it, pretty sure will solve the problems.