I'm having the same issue with the fuel temperature sensor, P0181 and it pops up as "service vehicle soon" essentially every morning.
Basically the same car, Astra J 1.7CDTI (A17 DTE engine, 81kW), year 2013. However, there is slight difference, I've disabled DPF. Around that time the problems (P0181) started.
I've seen OP's thread where he had it on sale:
https://www.vxoc.org.uk/forum/Thread-Ast...x-1-7-CDTI
He stated that a lot of parts were changed in the process, and that faulty DPF sensors were to blame. I do have sensors in place still though, but they shouldn't be in use since DPF is disabled.
I've already replaced the complete fuel filter housing with no luck.
Just this morning another Astra J with the same engine came to the repair shop where my friend works as a mechanic (it's independent shop, as they are very common in developing countries of South-East Europe). But that one is original, intact, with around 70k miles on the clock, throwing the same error.
Could this P0181 really be DPF sensor fault, despite that code relates to Fuel temperature sensor?
I wish I saw this thread before. I disabled DPF because of the extremely frequent regens, I'd be really mad if all of these problems (including my frequent regens) are actually due to DPF sensor fault. I'm mad already to be honest, I bought diesel car purely due to weak stock of petrol ones.
@Nuko-san, can you please share more details of your problem?
Thanks,
Vedran