Check engine light has been on for a week; only one code displays on my scanner:
P0597 - "Thermostat heater control circuit open"
I do not have any starting or drive-ability issues at all.
Has anybody had any success replacing the thermostat temperature sensor to fix this problem or does this code indicate the need to replace the entire thermostat assembly?
35,000 miles on my 08 Cooper.

 

Scott, this is actually not related to the engine temp sensor which you have spotted on the top of the black plastic thermostat housing. There are three codes associated with this unite 599 "Thermostat heater control circuit high", 598 "Thermostat heater control circuit low", and yours 597. Remove the airbox cover and then the intake resonator box from the snorkel. You will see at the bottom of the thermostat housing another connector. This actually controls the thermostat. If you are lucky this code could mean a loose connection (plug may be disconnected) or break in the wire to the unit. Otherwise this means replacing the whole housing since the thermostat and control are integral. An approximately $100 part and about three hours worth of work to get at the thing. I know I just did it but I had 93K on my mini (actually my wife's). There are several threads here on how to do it and they seem to be happening to Minis of all milages. 35K is pretty low for an 08. Any warranty left?

 

Thanks for your help. I pulled the intake resonator box to check that lower thermostat electrical connection. It was tight and the wiring was OK. So I'll be replacing the thermostat soon. One question popped up when I was examining all the connections that will have to be unplugged to expose the thermostat. It was not clear to me how to remove the brake booster vacuum fitting on the valve cover. It has a semi-circular clip at the base. Do you just press that in and pull? I didn't want to force it before understanding how it disconnects.

 

Not sure. Mine has antilock brakes so it has an electric pump with no vacuum line. There is a vacuum line connected to a circular housing off the forward cam shaft, it releases by squeezing the locking tab. A round multi pin connector on the sensor housing for the aft camshaft is removed by gently prying the locking loops (tabs) with a small screw driver or finger nail (one each side). The blue connector by the oil filter has a red locking tab (facing down) that is pulled out to separate the connector. There are two gray-beige zip tie fittings that you will just have to clip the zip ties out of and thread new ones in. The rest are pretty straight forward. Don't worry about removing the connectors from the spark plug coils, just pull them off the plugs as a complete unit. Label the connectors if you are unsure but they pretty well fall back into place. I recommend not opening a beer until after the harness is reconnected. You don't need to separate the plastic housing that harnesses all go into, it slides onto a tab that is part of the engine lift lug. If it doesn't want to unlock, one torx bolt removes the lug.
Hope this helps.

 

Here is the thermostat housing located on the driver side near the engine. You can see both connections , one at the top for the thermostat sensor, and one towards the bottom for the electric thermostat itself.


http://www.ecstuning.com/Search/11537534521/ES25098/




We also have the MINI OEM Coolant to finish the job.


http://www.ecstuning.com/Search/82140031133/ES196253/




For the brake boosters vacuum line near the passenger side has a line and it clips in. #1 in the diagram is the unit.


http://www.ecstuning.com/Search/11667556919/ES26449/ Cooper S version


http://www.ecstuning.com/Search/SiteSearch/11667570813/ Cooper " base " version






Lines



I believe that's what you are talking about.

Thanks and i hope that helps.

 

Thanks to all for the guidance. I replaced the thermostat (got it from ECS tuning) and everything is OK now.

 

Great news. Glad you were able to get things sorted.

 

Scott13, BC Clark and ECSTuning,

thanks for the info. this solved my problem and provided a part that i have been looking for forever...

 

You are welcome.

 

Glad to help!

 

Just got the P0597 code on our 2012 Clubman S and we only have 33K miles. Is this covered by warranty?

 

Should be if you are still under warranty. On my 2012 the warranty expires next month..

 

Common problem and yes it's covered under warranty. 48k odo and the dealership replaced ours twice, once under warranty and just recently out of warranty.

 

Just curious what else might cause this code - I just replaced the thermostat housing which was leaking coolant at the seal between the two piece construction. No code prior to the new housing install. After initial start up, this code appeared, within a day or so P0128 also came up. Again, neither was present prior to new thermostat housing install. I only replaced due to the constant coolant leak. I'm baffled....
M~