TCM Woes !

M

Museo

CCCUK Member
So after a 20 year wait I finally bought my first Corvette , a 2005 C6 T-top . And after a few weeks of no issues , a few days ago I got in , started up and was greeted by amber warning lights and a "Service Traction Control " message ,also when i drove the car it was in Limp mode and the speedo / HUD didnt work !! ....I took the car to a local Porsche specialist and he ran it through his diagnostics and it came back that the ECM ,BCM and IPC had "Lost communication with TCM ". It had an issue with this earlier in the year ( which i was aware of ) but it now looks like I'm looking at a new TCM and electrical check . These things happen and I guess that its part and parcel of having a Vette....anyway my question is this ... can anyone point me in the direction of an auto-electrician / garage near the East Sussex / Kent border who might be able to help out ! Love the car and want it back on the road . Thanks
 
B

Blackzed

CCCUK Member
Was the car difficult to start?
Asking because if the battery is weak it will lose connection with a lot of
modules while cranking.
It may be the battery itself, earth connection, battery connection.
They are very susceptible to voltage/ battery issues.
 
Pitre

Pitre

Chairman, CCCUK.
You need to read the obd2 error codes that have been generated. These messages are quite common and obd2 codes (+Google) will start to pinpoint the problems. It'll almost certainly be an electrical problem, or maybe just a bad battery or dodgy earth if you're very lucky...
There's lots of help online, particularly from the US owners forums.
 
teamzr1

teamzr1

Supporting vendor
As mentioned need to do a battery load test to assure it has the voltage, but also battery can handle the current load on cold startup
Look at the battery to see if someone replaced the battery but put the wrong type in and cannot handle the cold cranking amps required

Check grounds or ground splice packs close to the PCM, TCM and BCM

Take the passenger trap door off and under it is the BCM, a fuse panel, and the on-board network all controllers connect to
Assure no water damage or some animal eating the wiring
Check all wiring connectors wiring pins clean and firmly connected

See if there is any U comm codes tripped

Here is for 2005 C6, check wiring from TCM network wires as schematic shows

  1. To get to the PCM and TCM
  2. Jack up right front corner, take wheel off
  3. The rearward pat of inner fender, take screw off and that part of panel
  4. Behind that is where those controllers are
  5. assure all wiring connector pins and ground clean, good no breaks or was eaten
If in doubt spray with electronics or MAF cleaner
C505TCM.jpg
 
Last edited:
teamzr1

teamzr1

Supporting vendor
GM on purpose does their manual so cannot be printed well but here is the TCM, Tranny logic and wiring

C505TCM.jpg
 
M

Museo

CCCUK Member
Blackzed said:
Was the car difficult to start?
Asking because if the battery is weak it will lose connection with a lot of
modules while cranking.
It may be the battery itself, earth connection, battery connection.
They are very susceptible to voltage/ battery issues.
Click to expand...
No , the car starts fine and the terminals are secure . I believe its a fairly new battery as well . thanks for the info though
 
M

Museo

CCCUK Member
So it was the TCM ....all done now and the car is back on the road ....I was introduced to Matt from CCM Vettes Ltd and he sourced a new one , arranged for it to be programmed in the US , had it shipped to his workshop and then fitted it for me .... Cant say enough good things about him ... Top bloke !!
 
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