I have a 2014 Ford Escape Titanium with a 1.6 L engine. About two months ago I got a P1299 error (cylinder head overtemp) After reading some other posts I figured is was the cylinder head overtemp sensor, which I replaced. It fixed the problem for about a month and now I'm getting the P1299 alert again.

The engine it not actually overheating because the alert goes off before I make it 200 feet down the road. I turn the car off, reset the code, restart and see the engine temp is right at the halfway mark, right where it always is. Put the car back in gear, drive anither 100 feet and get another P1229 alert.

One if the oddities I've noticed is I can leave the car running in park for hours and it doesn't alert, but as soon as I drive a few feet I get the alert. I also noticed I can allow the car to slowly idle down the road in gear without any alerts, but I soon as I give it some gas, the P1299 alert goes off.

I'm stumped.

 

If you replaced the CHT sensor with a known good one,and the gauge is showing normal temp,
You might consider checking for a constant 5 volt reference voltage to the sensor and see if it is getting a false ground from the PCM.

 

Hi Hanky...I probably wasn't real clear in my first post. The Temp gauge goes from cold to pegged out hot as soon as the P1299 error gets thrown. This usually happens within driving 100 feet from my driveway so I know the engine cannot be overheating that quick. If I then shut the engine off, clear the code, then turn the car back on the temp is back to its normal range (between C and the midway point on the gauge) It will stay there until I put the car back in gear and start moving again, where it will throw another p1299 code and once again peg the temp gauge. I will check the reference voltage just to be sure. Thanks

 

The PCM would normally provide the ground for the CHT sensor based on info rec'd from temp sending unit. Suspect the wire , not the 5 volt wire, but the other wire from the CHT is rubbing through somewhere and getting a false ground.

 

Ugh...troubleshooting wiring issues is the worse. Thanks for your help, at least I've got a area to focus on now.

 

What I have tried in cases like this is to cut the wire that provides the ground someplace where it is easily reconnected maybe halfway between the sensor and on to the PCM..
Now if the problem is gone , we know the problem is after the cut on the way to the PCM. If we still have the problem , problem is between sensor and cut we made.
That would allow efforts to be a little more concentrated in only half the track. What do you think?

 

Sounds like a pretty good plan. Probably won't get to it today seeing how I'm suffering from L-tryptophan overload. (o:

Thanks for all your help and suggestions.

 

OK...so I pulled the connector off of the sensor and checked the two things mentioned above to look at.
In the first picture you can see that there is a hair over 4 VDC on the one line.
In the second picture you can see that there appears to be a dead short to ground on the other line.
I wiggled around all of the wiring bundles I could find, hoping that I would see the resistance drop at least momentarily so I could get an area to focus in on, but unfortunately the meter never wavered off zero resistance.

I'm afraid that I'm getting to the end of my technical abilities and that I may need to take it some where to find the short.

 

It is a wise man that recognizes when he is up against a tough problem and seeks competent assistance.