SPONSORED LINKS

Code P0700, PDK issues?

Tiny
OKRYACH
  • MEMBER
  • 2018 PORSCHE CAYMAN
  • 2.5L
  • 4 CYL
  • TURBO
  • 2WD
  • AUTOMATIC
  • 36,000 MILES
Hello guys. The vehicle listed above is a 718 S model. I am looking for any advice to help me figure this issue out. I bought the car a few months ago and it was driving flawlessly. Then on suddenly on a 45-minute drive home, I noted an error show up saying "Possible R gear failure" which was followed by weird acceleration behavior. I slowed down to pull over and it remained in 7th gear.

I put it in neutral and stopped and shut the car off. Started it back up and it showed R gear failed and "Engine Control Fault" error as well.

I waited a few minutes and started the car, it only showed "Engine Control Fault" and I was able to drive just fine, so I made it home. Hooked it up to diagnose and saw the P0700 error code and now it's in limp mode and Reverse doesn't work.

I accessed the TCM, and it seems to be abnormally hot, I tried checking the pins on the connector to see if something is shorting out but hard to do without a wire diagram, I'm seeing if a buddy of mine can retrieve one for me. I could buy another TCM but would still need to figure out how to program it for my car. But I'm not sure if that is the problem. Just wanting to start a discussion to see what others might think.

Any input would be greatly appreciated!
SPONSORED LINKS
Monday, September 30th, 2024 AT 10:39 AM

3 Replies

Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 47,642 POSTS
To me it sounds like you have a selector lever control unit that got wet or is shorted out which have seen before. Here is the transmission wiring diagrams so you can see how the system works. Check out the images (below). Please upload pictures or videos in your response of any problems so we can see what to help you with.
Images (Click to make bigger)
Thumb
Thumb
Thumb
Thumb
SPONSORED LINKS
Was this
answer
helpful?
Yes
No
Tuesday, October 1st, 2024 AT 10:42 AM
Tiny
OKRYACH
  • MEMBER
  • 2 POSTS
Hey Ken thanks for getting back!

I tried using those wire diagrams to test for short circuiting wire coming to the Transmission Control Module (TCM). However, it seems like those diagrams are incorrect.

I have 2 plugs that go into the TCM, grey and black one. I'll attach some images of them.

The grey plug has no pins with any active voltage.

The black plug has:
pin 14 w/ 4.8v
pin 26 w/ 12v
pin 28 w/ 2.3v
pin 29 w/ 2.8v

According to those diagrams, there should be 5v in pin 13, and 8.5v in pin 3. At least that's how I'm understanding it. Could you double check that the diagram is for a 2018 Cayman S please?

Also, one small adjustment to my initial post. I said the error code was P0700, but that's not correct. The current error code it's showing is P1706, don't know if that would change your opinion on anything.

Thanks Ken. Any further support is very appreciated!
Images (Click to make bigger)
Thumb
Thumb
Thumb
Was this
answer
helpful?
Yes
No
Tuesday, October 1st, 2024 AT 8:11 PM
Tiny
BORIS K
  • MECHANIC
  • 799 POSTS
Hello,

The wiring provided by my colleague seems correct, below is the pin out for the black connector.

You appear to be missing 12V ignition feed at pin A34, black/red wire.
This is fed by fuse F7(5A) in front right fuse block, row D.

Your voltage readings:

The black plug has:
pin 14 w/ 4.8v - starter lock signal from DME, violet/yellow wire
pin 26 w/ 12v - constant 12V, red/blue wire, should also supply pin A5. Supply from fuse F4(25A) in front right fuse block, row C
pin 28 w/ 2.3v - CAN bus low, correct
pin 29 w/ 2.8v - CAN bus high, correct

The grey connector supplies the transmission valves/solenoids.
Disconnected there will be no voltage feedback as the supply is missing from pins B2, B18 and B25.

Cheers, Boris
Image (Click to make bigger)
Thumb
Was this
answer
helpful?
Yes
No
Wednesday, October 2nd, 2024 AT 3:50 AM

Please login or register to post a reply.

Sponsored links