2019 Mustang GT Premium Overheating issue

[Jaxstang]

I agree. This is what I told them too. Suppose the scan didn’t return any meaningful code. I picked up the car this morning and on the way to work the check engine light came on. Everything seems to be working fine this time so the engine light might be a lose connector or something when they put things back together after replacing the cylinder head sensor. Nonetheless, back to the dealer tomorrow for the 3rd time to check why is the check engine light in this time. I called the sales guy and he gave me a managers name to ask for when I go there to see what optiwe have. I told him I was very close to start the Lemon process if I have to return again. Very frustrating to have a brand new car and only drive it to the dealer each time because it is broken. I don’t even trust at this point that I can take it to my Orlando trip Friday (about 2 hours drive each way). We will see what the story is tomorrow.

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[Jaxstang]

Car seems to be finally fixed. The last check engine light was a lose conection on one of the sensors they worked on. I took it on a 400 mile round trip with no issues. I’m in love with the car again. Now on to some changes such as indoor light with a Diode Dynamics kit and possibly a higher flow filter. Sheers.

 

[Demwin11]

So what the problem in the end. My 2019 cs/gt just give me engine coolant over temperature. Is this the same code u read.

 

[nonozor]

HI , i subscribed to the forum also to add my contribution on the problem list. I just add the same problem. The Engine coolant alarm raised while driving while no overheating, cylinder heads temp ok , and the engine coolant temp value went back, so maybe false contact. The engine then goes into security mode on 4 cylinders, i drove back home without problem with the engine overcooled ... they are changing the sensor atm , but i think this is a wiring problem. More info from the garage next week. Really scary and frustrating after 800 miles.... connexions on all wiring seems loose and sensible to car movement/vibrations , i would like to tape all that so the accelerations forces does not move the little connected wires . Sensors are not to blame for me , this is simple thermal resistance. But the wires seem not very tough.

 

[nonozor]

HI , i subscribed to the forum also to add my contribution on the problem list. I just add the same problem. The Engine coolant alarm raised while driving while no overheating, cylinder heads temp ok , and the engine coolant temp value went back, so maybe false contact. The engine then goes into security mode on 4 cylinders, i drove back home without problem with the engine overcooled ... they are changing the sensor atm , but i think this is a wiring problem. More info from the garage next week. Really scary and frustrating after 800 miles.... connexions on all wiring seems loose and sensible to car movement/vibrations , i would like to tape all that so the accelerations forces does not move the little connected wires . Sensors are not to blame for me , this is simple thermal resistance. But the wires seem not very tough.

the final word: The engine coolant temperature sensor was dead, in shortcut. Bad piece, bad luck. The replacement was not easy because it is hidden behind the engine , so the upper admission part must be removed.

 

[dm.15]

I am having a similar issue with my 2019 Mustang with just over 1,150 miles from new. Had car on cruise at 70mph, temp gauge dropped from normal temp to zero followed by an overheating warning despite block temp still reading as around 90c.
Got recovered to dealership and after 2.5hours with the engine off the issue is still present.
Dealership found multiple fault codes due to a shorted electrical wire (mounted poorly on a sharp bracket) but seems the short has caused the coolant temp sensor to fail. Intake manifold (and several other key components) need to come off now for them to access the faulty sensor and assess if pcm is also faulty.

 

[nonozor]

I am having a similar issue with my 2019 Mustang with just over 1,150 miles from new. Had car on cruise at 70mph, temp gauge dropped from normal temp to zero followed by an overheating warning despite block temp still reading as around 90c.
Got recovered to dealership and after 2.5hours with the engine off the issue is still present.
Dealership found multiple fault codes due to a shorted electrical wire (mounted poorly on a sharp bracket) but seems the short has caused the coolant temp sensor to fail. Intake manifold (and several other key components) need to come off now for them to access the faulty sensor and assess if pcm is also faulty.

it seems the same problem with faulty sensor, they must have received bad 3rd parties sensors recently ?.

don't worry , after the swap , the engine should work like a charm. But note that , for me they had to reset all due to battery disconnection. So the software will relearn the engine , at first the temp value will be oscillating between 88c to 94c, and you will have blinking engine alarm when engine is off . After few km (20 i would say) and a few restarts, all will be ok.

 

[dm.15]

it seems the same problem with faulty sensor, they must have received bad 3rd parties sensors recently ?.

don't worry , after the swap , the engine should work like a charm. But note that , for me they had to reset all due to battery disconnection. So the software will relearn the engine , at first the temp value will be oscillating between 88c to 94c, and you will have blinking engine alarm when engine is off . After few km (20 i would say) and a few restarts, all will be ok.

Thanks for the info! Seems it’s not so much a bad batch of sensors but poorly mounted wiring loom. This causes a short on the sensor circuit and then blows the sensor (and potentially can damage the pcm too. Still waiting to find out on that one).
How does a partial engine rebuild such as this affect overall performance of the car? Given almost half the block is being torn down and then put back together I can’t see it ever being the same again!

 

[dm.15]

Thanks for the info! Seems it’s not so much a bad batch of sensors but poorly mounted wiring loom. This causes a short on the sensor circuit and then blows the sensor (and potentially can damage the pcm too. Still waiting to find out on that one).
How does a partial engine rebuild such as this affect overall performance of the car? Given almost half the block is being torn down and then put back together I can’t see it ever being the same again!

UPDATE: Broken down again and Ford are now going to replace the car. Hopefully the wait is shorter this time than the 6 months I waited last time!!

 

[twalker6800]

Same thing happening with my 2019 Mustang GT...bought 3/30/2019

 

[nonozor]

i did not have oscillating values like yours. The values on cylinder head were moving due to the protection mode that was activated , running on 4 cylinders. my symptom was a big alarm for overheat temp (sensor in shortcut). the cylinder temp seems to move a lot in value, mayge there is several and the computer switches from one to another. but at least sensor/wires need examination. No worry on the engine , mine is working perfectly after running 25 miles on 4 cylinders.

 

[twalker6800]

i did not have oscillating values like yours. The values on cylinder head were moving due to the protection mode that was activated , running on 4 cylinders. my symptom was a big alarm for overheat temp (sensor in shortcut). the cylinder temp seems to move a lot in value, mayge there is several and the computer switches from one to another. but at least sensor/wires need examination. No worry on the engine , mine is working perfectly after running 25 miles on 4 cylinders.

Got mine back from Ford, replaced the CHT sensor and so far back to normal....I would occasionally get the overheat temp alarm as well

 

[nonozor]

good news , so not the same sensor replaced, they have a quality problem on heat sensors parts it seems.

 

[TX-Ripper]

does anyone know the location of the sharp corner damages the wires?

 

[Cobra Jet]

Ford TSB 19-2049 for the overheating issue:

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