Help Please Problem with temperature and dpf

[Dominika4]

Hey so i have an odd situation the display temperature is constant at 50 when my ac is on ecu fan turns on as soon As i start the car and keeps coolant temp at 50 when i turn the ac off in car the dashboard display goes up to around 65-75 after dricing for around 30min if i give it high revs it climbs slowly but as soon as i stop reving it drops back down to around 60.. i just had my thermostat replaced but that didn't do much and now 3days ago my particulate filter light came on my guess because the car cant heat up and is not able to recover itself


Has anyone experienced anything like this the mechanic told me at this stage to chrome out the dpf but i dont feel like this fixes the problem.

AUDI A4 B8 AVANT 8K5 2.0 TDI (143 HP)2009 automatic​

 

[spartacus 68]

Interesting. Noted yours is an auto, and possible DSG gearbox. I wonder if it’s inline coolant thermostat. Sometimes called second thermostat. Buried at back of engine.

 

[Dominika4]

Interesting. Noted yours is an auto, and possible DSG gearbox. I wonder if it’s inline coolant thermostat. Sometimes called second thermostat. Buried at back of engine.

Do you know the price range to get that change i haven't tried that yet my next step will be outting a new collant sensor and a gas temperature sensor trying to eliminate all possibilities one by one

 

[spartacus 68]

Have a read of this and importantly Dave Sterl’s video. https://www.audi-sport.net/xf/threads/444146/

 

[400ixl]

Have you had it read for any error codes?