2007 mini cooper s is throwing a p0128 and a 2F07 code and was wondering if i just need a new thermostat or what. it doesnt seem to be leaking coolant and it only happens usually on my way home from work, which is at night. i cleared the code tonight and after 15 minutes and 68 degree farenheit weather it threw the code when the coolant was 76 degrees celcius. on my way to work today before i left i cleared the code and it did not come back on but after a 30 minute trip the coolant only reached 90 degrees celcius. any help would be appreciated.

 

Probably just a bad coolant temperature sensor reporting colder than normal operating temperatures, this should be your first step and cheapest route. If you find you're still getting the same codes after clearing them from your ECU it's your thermostat housing, have you ever replaced your thermostat housing before? Usually they only last 45-75,000 miles, climate has a lot to do with failures like morning temperatures 30 degrees cooler than afternoon temperatures. The newer thermostat housings have been revises which hopefully means they'll last longer, but I'm still changing mine every 50,000 miles simply because there made from plastic when they should be made from aluminum.

http://www.samarins.com/diagnose/p0128.html#causes

 

Here is a thread on NAM for both codes listed. Cause is improper water temps and therefore he replaced the thermostat housing, temperature sensor, and flushed the coolant. All resolved his issue.

If needed - Thermostat with housing and gasket 11-53-7-534-521 here. Coolant temperature sensor 13-62-7-535-068 here. Use MINI coolant 82-14-0-031-133 here. Coolant DIY here. Thermostat DIY here.

Hope this helps, let me know if you have any questions.

 

See here for more info:

https://www.northamericanmotoring.co...ugh-start.html






Sometimes its the water temp sensor itself.