Hi everyone, I have a 2019 Fiesta ST.

The other day I was driving through Germany, I started accelerating hard and after about 15-20 seconds at 190km/h the engine warm-up warning light came on, just when it came on I stopped accelerating and 1 second later the warning light returned to the normal temperature. , I stopped but I didn't see anything strange, the oil was good, correct coolant, etc. 

After 4 days I took the autobhan again, I did the same and the warning light came on again, after returning home I went to the garage and I had a cylinder head overheating fault.

But the fact is that the car runs normally, I can do full acceleration from time to time and the warning light does not come on.

What could this be, the thermostat, fan, radiator...?

Has anyone else had this problem?

The car has 110k km.

I would suspect the thermostat before anything else.  Can't recall seeing anyone else with this issue on that engine though.

Maybe the cylinder head temp sensor is just very sensitive.  It would be ideal to see live data of the temp when the fault occurs.

Yes, it just what I thought, I will try to do the same thing with a scan to see the real temperature

Thanks, I will back to you if I find something 

Which light was it, the one that looks like a Thermostat beside the Temperature Gauge?

Yes, it just that

But this week we did a test and we saw the temperature going to 92 degrees to 195 in just 1 second and this time it hasn't go off, so come to my oncle's garage and we saw a 3 default, P1026, P1285 and P1299, so we think that there's a problem with the head gasket temperature sensor and the refrigerant temperature sensor.

So tomorrow we going to change that and see if it was that.

If not we're going to check the thermostat. 

You really need to Live Monitor the Coolant, Cylinder Head and Oil Temperatures with the car running.

If the car is genuinely overheating then all 3 Temperatures will be too high. With normal driving they will be very near to each other, with the Cylinder Head Temperature probably rising a little bit faster than the others. 

FORScan is an excellent and cheap tool for Live Monitoring. there may be others that will show you the same results though.

Well, i changed the two sensor but it was the same thing

i did the same test with a scan but this scan it only shows the coolant temperature,

So, when the light came on, the temperature it was 92 degrees in the scan and the temperature gauge it was 120 degrees,

This time it came back to 90 degrees in 1 second when I stop to accelerate 

And a default it came on in the scan, it was P1285, cylinder head overheating

It’s really weird this thing, so I think I’m going to talk to a Ford dealer if they find something with the FORScan

22 minutes ago, elu said:

So, when the light came on, the temperature it was 92 degrees in the scan and the temperature gauge it was 120 degrees,

From the limited information I have, that is what happens when the PCM thinks that the Cylinder Head Temperature is too hot, I presume it is another way of alerting the driver.

It could be a wiring fault or a fault at the PCM.

Yes, maybe it's that, a fault at the PCM, because it did that when you accelerate hard for like 15-20 seconds, 

But a I just talked to a ford dealer and he told me that it could be the water pump because it only happens in the hard acceleration like that, even when I go a little hard in a mountain road it doesn't happens so maybe the water pump can't handle a long charge or like you said TomsFocus, it could be the thermostat 

And that's why you need to Live Monitor all the Temperatures. If the Coolant Pump was not working correctly I would expect the Coolant Temperature to be higher than normal just before the Fault Code was registered, the Temperature jumping up high then back down again instantly is intended behaviour for the P1285 Fault Code as far as I know.

The P1026 Code you had earlier is a correlation Code, the PCM detected that the Coolant and Cylinder Head Temperatures were not nearly the same as each other.