2012 XC 90 won't start TCM issue

206driver · Post by **206driver** » 23 Apr 2019, 15:20

I own an 2012 XC90 that is having starting issues. In November 2018 it would not start. Towed to dealer and they stated the Transmission Control Module was offline. It was rebooted and was back online and vehicle started and ran fine. Dealer note said they did not see any reason for TCM going offline, and if it happened again the TCM may need to be replaced. Today it would not start (totally dead, with good battery). Has anyone had this issue and did you replace the TCM? Location of TCM in this vehicle so I can start looking to replace it?

Post by **precopster** » 24 Apr 2019, 01:39

In engine bay next to coolant bottle under a plastic cover. The ECM is the module next to it.

Did they clean, disassemble the casing to view the board and look for corrosion? Have you been washing the engine? Way too many connectors in hard to reach places to justify wetting the engine bay, even if excessively greasy.

wanderdüne · Post by **wanderdüne** » 24 Apr 2019, 10:34

You can't just replace the TCM, it needs to be programmed to the car. You can either go through a service like XeMODeX or through a dealer or indy with dealer level tools. I don't know if you can DIY with VIDA-dice, maybe if you have a OEM legit setup and can get the programming from Volvo.

Post by **RickHaleParker** » 24 Apr 2019, 12:28

The 2012 XC90 has the TF-80SC transmission. The TF-80SC TCM is mounted on top of the TF-80SC.

If you change the TCM on a TF-80SC you will need a software reload at a Volvo dealer or you will need to hire somebody to clone the software from the old to the new TCM. From what I can see Xemodex does not offer a cloning for this TCM. A Volvo dealer might be your only option.

Check the wiring and connectors, dirty, opens and shorts before committing to a new TCM. The fact that the dealer could not find anything strongly suggest an intermittence problem. Most common cause of a electronics intermittence problem ... wiring.

206driver · Post by **206driver** » 24 Apr 2019, 20:14

Thanks, will check wiring and connectors for issues before going for replacement. Will have to repair this as it’s been a great car.

Post by **xHeart** » 29 Apr 2019, 07:50

206driver wrote: ↑23 Apr 2019, 15:20 I own an 2012 XC90 that is having starting issues. In November 2018 it would not start. Towed to dealer and they stated the Transmission Control Module was offline. It was rebooted and was back online and vehicle started and ran fine. Dealer note said they did not see any reason for TCM going offline, and if it happened again the TCM may need to be replaced. Today it would not start (totally dead, with good battery). Has anyone had this issue and did you replace the TCM? Location of TCM in this vehicle so I can start looking to replace it?

If you're not a DIYer AND your XC90 is out of manufacturer's warranty then watch your pocketbook, trade it off for newer.

Post by **precopster** » 29 Apr 2019, 22:20

I would start by unplugging all TCM connectors and cleaning with contact spray then plug and re-plug to scrape off corrosion. The same could be done at CEM. I would employ an auto electrician for this job if you are not handy with cars. Mechanics to be avoided for this one!

206driver · Post by **206driver** » 30 Apr 2019, 18:42

Thanks for the advice on cleaning, checking wiring etc which I plan to follow first. I have a fair amount of diy repair experience, but first foray into Volvo. If I end up having to put in a new TCM, it looks like the procedure will require tool 9997262. Fortunately this is an extra car for me and I can take my time. Have located someone who can come to my location to reset TCM, instead of a tow to a shop. Will let everyone know how this comes out