2014 Fiesta ST Temp Gauge Maxes out with car in accessory SOLVED

[Z06 Kenny]

Hey ST Forum,

I’ve had my 2014 for about 2 years now and it’s been great, but I’ve run into an issue which turns the car into a paper weight. On the way home from work last week my car dinged at me 2 minutes down the road and I looked down to find the temp gauge was maxed out (oh sh*t moment). I pulled into a nearby parking lot to see what was up. I found there was a small leak in one of the lines coming from the reservoir, I had a friend bring me some 5/16 fuel line we fixed what we though was the issue and yet the temp gauge was still pinned upon starting it up. The strange part is when the car is in accessory mode it still maxes out, which led me to believe it’s an electrical issue. I replaced my temp sensor with no success. The fans are working, the coolant hoses are warm, it just doesn’t make sense. Anyone have any ideas? I’m going to try and borrow a code reader from O’reilys right now and I’ll let you guys know what codes I have. Thanks in advance guys!

TLDR; 2014 Fiesta ST is “overheating” in accessory mode and after the car has been sitting. Replaced coolant temp sensor, fans work, coolant hoses are warm.

 

[D1JL]

If you can read the PCM codes, it may tell you something.

 

[Z06 Kenny]

Okay guys fixed it, it was a p1299 code, I borrowed a code reader, cleared the code and the temp gauge went down before I could unplug it. Drove it 15 miles or so and the temp never went past halfway. I’m guessing once there’s a fault that causes the vehicle to go into limp mode you have to clear the codes to get it out of it regardless of the issue was fixed (in my case the coolant temp sensor and that small leak). I’ll keep y’all updated if it happens again. Cheers.