Tech question

[ChrisL]

So about a month ago I had the cam sensors replaced. When I got it back I noticed the temperature gauge was displaying and actual number right above the gauge itself. Took it back in and after 10 days they said it needed a new PCM because the current one would not take the new program from Ford. It would display this number when I would let off the gas, then it would cool down and go away. Ford said the “shutters” weren’t opening correctly. Ok so, they replaced the PCM and finally got a good program to take. Picked it up on Friday and it still does it. The field engineer said it’s normal to “flash” 230 and then cool down. I have never noticed this before and only noticed it after the cam sensors were replaced and the computer reprogrammed. Had anybody else seen this problem??

 

[K223]

Trying to piece together what your saying. But normally the actual temp number is never displayed unless you use Forscan to enable it. So something was enabling it. Now later on was it just flashing at 230 only and then would go away after you cooked down? I have never got anywhere near 230 before. Was the truck under a lot of load? Sounds like you were using the truck as you normally do and never saw it that hot before. Something seems abnormal.

 

[ChrisL]

I had an ATV in the bed and was pulling a 2000 pound camp trailer. We were driving normal and the temp number would flash 230, 234, 239, 240 and got as high as 249. No lights came on and the truck ran just fine. I’d let off the gas and the temp would go away. No, when I’m on the gas there’s not temp number but when I let off the gas after spooling up those turbos, the temp number appears. Yesterday it got to 234 and then goes away. Does that make sense? It’s a dam mystery

 

[CoronaRaptor]

The coolant level is good in the reservoir , correct? When cold its at the cold line, when hot at the hot line.
@FordTechOne might have some insight.

 

[ChrisL]

Correct. Coolant levels are all good. The dealership had it for almost 2 weeks and all I was told was that it was a “programming error”.

 

[FordTechOne]

I believe the Instrument Cluster is designed to display the actual temperature when the engine temperature is above normal operating range.

Did you pull the same trailer and payload before without any issue? 249 degrees F is definitely not normal. My best guess is the ECT sensor or wiring was damaged during the repair and is now reading biased, because if the engine was actually that hot the PCM should be setting overheat DTCs and warning messages. The PCM relies on the Cylinder Head Temperature (CHT) to determine overheating, so if the CHT is reading normal temps it will not enter an overheat strategy.

Have you verified if the engine cooling fans are working? If set turn the climate control to Max A/C and turn the fan to high the engine fans should come on.

 

[ChrisL]

I believe the Instrument Cluster is designed to display the actual temperature when the engine temperature is above normal operating range.

Did you pull the same trailer and payload before without any issue? 249 degrees F is definitely not normal. My best guess is the ECT sensor or wiring was damaged during the repair and is now reading biased, because if the engine was actually that hot the PCM should be setting overheat DTCs and warning messages. The PCM relies on the Cylinder Head Temperature (CHT) to determine overheating, so if the CHT is reading normal temps it will not enter an overheat strategy.

Have you verified if the engine cooling fans are working? If set turn the climate control to Max A/C and turn the fan to high the engine fans should come on.

Ive pulled the trailer but the ATV is new, so no. Yes, the cooling fans are working as I can hear them come on. No other warning lights or anything else comes on and the truck continues to run just fine. Truck has almost 35k miles on it.

 

[FordTechOne]

Ive pulled the trailer but the ATV is new, so no. Yes, the cooling fans are working as I can hear them come on. No other warning lights or anything else comes on and the truck continues to run just fine. Truck has almost 35k miles on it.

Strange. In your profile pic it appears you have a light bar behind your grille; have you tried removing than and re-evaluating? Even if it’s not blocked a significant amount of airflow, it could be causing turbulence which will inhibit airflow through the radiator.

 

[ChrisL]

Strange. In your profile pic it appears you have a light bar behind your grille; have you tried removing than and re-evaluating? Even if it’s not blocked a significant amount of airflow, it could be causing turbulence which will inhibit airflow through the radiator.

Really? Wow, I had never thought of that, but its been on there for some time and this is the first time any of this has happened. I am beginning to agree that these are false readings as no other lights or warnings are coming on

 

[FordTechOne]

Really? Wow, I had never thought of that, but its been on there for some time and this is the first time any of this has happened. I am beginning to agree that these are false readings as no other lights or warnings are coming on

Is this the first time you’ve towed/hauled that much weight though? I’d remove it and see if the temps return to normal.