[Dom083]

I have an F30 2013 335i xdrive. I am a college student, who goes to school on the East coast and lives in CA. I recently went home for winter break. My car stayed with a family member who turned it on every few days. It is cold in New England this time of year, not sure if this is a factor with my probelm.

Anyways family members let me know that the check engine light is on. At one point I tried to have a cousin use my OBD cord w a lightning cable adapter to read codes off BM3. For some reason my cord will not connect to the vehicle. But that is my smallest probelm right now (in the past I have disconnected battery and reconnected and it worked).

Right now I have a check engine light with the following codes
U1408
P0128

These seem to be the culprit and are both coolant related issues. I have been doing seem research online. Keep in mind I am a complete amateur/novice lol. Seems that my engine coolant temperature sensor is invalid. I have seen multiple fixes for the issue. Solutions as simple as low coolant, others simply replacing the sensor, and others suggesting replacing the thermostat (as it can get stuck open i belive?). Anyways I’m not sure how to go about this problem. Has anyone else had a similar problem with their n55? Anything helps! Thanks.

[thejeremyman9]

Well you didnt post the code descriptions, but assuming they are coolant temp sensor codes, i would check what the car is showing for coolant temp. check this via hidden menu on the dash (google it) and via BM3 or another app that connect to the DME.

Does the car actually have any symptoms? If the thermostat was stuck open the car would probably never get up to temp while driving, especially in cold weather.