Transmission service required and boost leak??
 

Hi, I have a 2004 d5 Xc90, I know the intercooler needs replacing as there is a leak on it after doing a smoke test.

Issue is when towing I get a transmission service required and it locks itself into 4th gear on auto box, I I'm told and I'm questioning it here that a boost leak on intercooler could potentially cause this fault, Is that correct or am I being told a load of rubbish??
Tia

Not linked as far as I know. A boost leak can generate lots of DTCs but not a TCM fault.

They’re unrelated. Getting the codes read, transmission fluid change and software update is your first steps.

I had something similar if not the same. Same message and I only got it on towing and normally when foot was off the accelerator and caravan 'pushing' the car - like going down a hill. Vida dice told me it was some lock up function related to some lock up clutch in the auto gearbox. Some people said a coolant leak into the transmission via the oil cooler could cause that as the coolant eroded the clutch material. I was lucky, my gearbox oil level was low as I had been measuring it with the engine switched off. Apparently, the oil level in early XC90 auto gearboxes should be measured with the engine running-perhaps someone can confirm this before you try it? Anyway, I topped my gearbox up and never got the problem again.
Hope this helps and keep us updated.

Yes, with the engine running

That has been the case for many years... not just on the XC90 either. The P3 models of the V70, S80, XC70 from 2006 onwards are the same for example. In fact, I think the transmission fluid level needs to be checked with the engine running on the very latest models available too (up to 2021). Its also worth noting that the engine doesn't just need to be running, the transmission fluid also needs to be between 50 & 60 degrees to get an accurate reading.

....and on level ground.