1999 V70 - Swapped transmission- codes retained by TCU?

ferocity02 · Post by **ferocity02** » 14 Nov 2018, 13:58

I had TCU codes that would never clear even after the fault is corrected. The flashing up arrow would go away but the check engine light would remain illuminated. Scanning with VolFCR revealed a TCU code along with an ECU code indicating that a TCU code was present. Most obd tools wont clear this. Only VOL FCR and disconnecting the battery cleared it.

Post by **precopster** » 14 Nov 2018, 14:07

This is a 1999 model fitted with the wrong (1998) transmission sensors that weren't swapped over during a transmission swap. 1998 sensors are not compatible with a 1999 TCM

Vol FCR will not work with this early CAN vehicle and in some instances has been known to damage one of the computers.

Best to scan with Vida/Dice or a generic scanner

JuliusC · Post by **JuliusC** » 14 Nov 2018, 19:39

Thank you every one for sharing your experiences - I will be taking the car to an independent Volvo shop in the near future and they will do a scan as well as clear any codes, and possibly they just might go away on their own when I finally drive the car on the road. This has been interesting learning about the systems unique to the 1999 compared to earlier years.

Hopefully the reputation of the AW 50-42 as being a basically long lived transmission will hold, unfortunate that the original to this V70 was contaminated by coolant and rendered useless and the first replacement by water mixing with the atf from improper longer term storage, it only had 145,000 km on it apparently, originally from a 1999 S70.