Thermostat Heater Control Circuit / Open P0597

[hotdogsandrice]

Hello!

2020 Audi S4 ~ 55k miles:

• P0597 - Thermostat Heater Control Circuit / Open
• Check engine light is on

I am just confirming if the thermostat is the culprit here? The heat is running fine and my coolant temps look normal. There is no overheating. I am getting reduced MPG though.

On days where the temps are below freezing I also get the "Coolant too low - please turn off car or something" but it rarely pops up.
My brothers S5 had the "coolant too low" issue and the dealership / indie shop recommended to replace the thermostat but I ended up fixing it by replacing the solenoid valve so maybe I should try to do that first since it's a cheap fix?

If thermostat is most likely the culprit, should I do any other work while the front end is out?

Thanks!

[hotdogsandrice]

So I will be doing the thermostat / water pump / and coolant shutoff valve soon. I have downloaded the erWin manuals and it is slowly making sense on how to put the car into carrier lock position ( front bumper, crasbut I cannot for the life of me find the lock carrier tool set they use. Am I looking at the wrong sections or something? T10093 is the part number used for the previous versions. Would this work?

I also will make an A-Z guide ( ADHD mind ) on how to do these procedures after re reading the steps multiple times with the manuals if anyone is interested lol.

[Andy_FL]

So I will be doing the thermostat / water pump / and coolant shutoff valve soon. I have downloaded the erWin manuals and it is slowly making sense on how to put the car into carrier lock position ( front bumper, crasbut I cannot for the life of me find the lock carrier tool set they use. Am I looking at the wrong sections or something? T10093 is the part number used for the previous versions. Would this work?

I also will make an A-Z guide ( ADHD mind ) on how to do these procedures after re reading the steps multiple times with the manuals if anyone is interested lol.

Most people just use a long bolt to 'hang' the carrier on. Don't know the exact size but just make a run to the local hardware store once you get it disassembled.

[hotdogsandrice]

Thanks guy. Don't mind me everyone just using this thread for reference to make sure I don't miss anything.

Repair manuals used:

• D4B805BF218-Body_Exterior
• D4B8067F7B8-Servicing_-_6-Cylinder_2_9L__3_0L_4V_TFSI_EA839_Engine
• D4B8068C0C1-6-Cylinder_Direct_Fuel_Injection_2_9L__3_0L_4V_TFSI_ Engine_EA_839

https://www.youtube.com/watch?v=6nWeA1coBHQ&t=392s:

• One of the commenters noted this: m8x1.25 Thread pitch think there 100mm from memory

https://www.audiworld.com/forums/a6-...369-a-3015745/

• Read later

https://www.youtube.com/watch?v=1GQkQhXBNpE&t

• How to take out front bumper

https://www.audiworld.com/forums/att...364d1609395727

• EA839 Self Study Program

[Goped220]

Is the car tuned?

[hotdogsandrice]

The car was bone stock absolutely no mods. It's merlin purple though :)

[hotdogsandrice]

The repair manual says to use T40425 ( thrust piece ) to install the seal for the thermostat. Is this required or what would I do specifically to make sure it's mounted properly?