Drilled into my car today to check for faults, and saw this one...

Has any one seen this code? Thoughts? Does this mean my thermostat is on its way out? I wasn't getting any overheating or overcooling issues. I had cleared it, but it came back

 

My 2014 clubman has a similar code...I plan on replacing the thermostat and call it a day lol

 

The thermostat has a heater in it so the ECU can directly control engine temperature. If it fails the thermostat will still work passively (so it will not overheat) but the temperature may not be as-designed and you'll get faults. So basically it sounds like you need a new thermostat assembly.

These cars have had tons of thermostat leak and electrical problems. The original thermostats had a temperature sensor that would fail, the fix was to retrofit another sensor into one of the upper hoses. The new thermostat assembly that's available has an improved temperature sensor in it and I believe you need a wiring harness adapter. It can be a bit tough to figure out exactly what parts you need for the fix as there have been multiple mods and variations over the years and it may depend on what you've had done to the car.

 

I had found the service bulletin last night when I was searching the code. I poked around the engine bay this morning, and saw that I do have the revised thermostat and harness adapter. Driving over to Lowes today, I monitored the engine temperature, and it appeared to be controlling, but with much wider swings than usual. (oscillating between 170-190°F) Sounds like my thermostat is behaving just like Gubi described.

Looks like it will be a bee-otch to replace , but I guess I should put it on the list. I was contemplating a coolant flush anyway....

 

Well, I officially got a check engine light for the thermostat yesterday

Now I have to put together a list of parts. Any recommendations for items to be included in a cooling system refresh?

So far, I'll be ordering a new thermostat, harness adapter, and water pipe. I'm contemplating silicone coolant hoses, and adding a dedicated coolant temperature gauge with the M7 coupling adapter. My overflow tank still looks clear and not yellowed.

Just checked my records, and the water pump has about 60k miles on it... It isn't leaking, and I don't really want to get down the rabbit hole on that side of the engine just yet.