Hi all,
Ok, son's FEH tripped a code last week. Read it as P0128 which indicates coolant temperature out of range. After some investigation, I purchased a new cylinder head temperature sensor and replaced it. Wiring was good, no corrosion etc. Next day it showed the CEL again and tripped P0128. Most history of this is a sticking thermostat, so I ordered a Ford thermostat and housing. OMG what a PITA to change that. Anyhow, it is all done and hopefully that cures it but I also ordered a temp sender unit listed for the idiot light. I cannot find where this sender is located. Anyone know????
Thanks

 

Try to find it: http://www.nicksmustangranch.com/Ser...e%20Manual.htm

Also would be good to read all those sensors with a scan tool and see if they are really broken.

 

Unless I'm mistaken, the idiot light on the dashboard is for coolant overtemp, not coolant undertemp, and is independent of the check engine light, and driven by the engine computer.

My understanding of the '08 models is that the computer uses the cylinder head temperature reading to infer the engine coolant temperature and there is no separate coolant temperature sending unit (there is also no gauge or traditional dashboard readout for coolant temperature). This was changed somewhat on the '09 models.

See the following thread: https://electricvehicleforums.com/fo...ck-open-28850/

Why did you think you needed to buy a new sending unit? Who or what told you to get one for an '08 FEH?

 

Thanks guys. Son had the p0128 code..he had it read at oreillys. They advised him it was stuck open thermostat and possibly coolant temp sensor. He ordered parts. When they arrived i went by and picked them up and realized they sold us correct t-stat but sensor they sold us appeared to be for gas escape with coolant temp gauge. I returned both of them and purchased the cylinder head coolant sensor that is correct for the escape hybrid after reading the various service bulletins about the corrosion etc. I replaced it but there was no corrosion at the connector or around the sensor and reset the DTC code. a day or so later CEL returned and i read it as p0128 so ordered a thermostat housing/t-stat from rockauto. Their catalogue also lists a coolant temperature sensor for escape hybrid with idiot light so just in case ordered that too.

 

I am betting the new thermostat will fix it. If it was sticking closed, you were getting high temps in the cylinder head and little to no effective cooling. You should also be able to run the heater and tell right away if the car is warming up properly and coolant is flowing. Be careful because keeping the car running in that condition with a stuck-closed thermostat (I'm not sure if it will cut the engine by itself) will blow the head gasket. By the way if you need coolant, the spec is: WSS-M97B51-A1. You can use Zerex G-05 as an equivalent. The '09 models have some kind of monitoring system on the thermostat housing, from what I have read, but not your car.

If I'm wrong someone please let us know.

 

I did the repair Friday night and refilled with Zerex g-05; son drove to work yesterday then on a trip about 2 hours away afterwards. He returns tommorow on a 2 hour return trip so will see how it went. Oh and when i was refilling, i purged the system of air and the heat was working well so...
Cars of any type without a temperature gauge are so annoying.

 

Agree 110%. Mind boggling to me on this car especially, which was marketed with the premise that buyers were more attentive types who geeked out on every number. At least give a readout selected through the Information Center in the cluster, along with oil pressure and I also want tire pressure on a per-wheel basis and an honest-to-God fuel pressure reading off the rail. This is silly stuff on a car targeted at that market which could cost north of $30,000 in 2008 (almost $40,000 or Mercedes CLA money today).

Here's what you can buy for < $40k today and when these cars were in their heyday they were about the same price and - if anything - bigger Nerd Magnets as the ScanGauge depository shows.

https://www.truecar.com/best-cars-tr...e-under-40000/

 

The temperature gauge in most cars is a dummy gauge. You can see "too hot" and "too cold" or "just right" assuming its not a light. OBD pid give you a real temperature reading. Real gauges were mostly addon and aftermarket past the 80s. Plus we have 2 separate cooling systems, what should the temperature be for? Mecs? Radiator? Battery?

You don't have per tire pressure but you have per wheel brake pressure... so there is that. Those luxury cars have the sensors and that's nice until they fail and you have all those expensive parts to replace. Mercedes is a big nightmare for that and everyone says don't buy them used. BMW too, along with shoddy engines.

If one really wants all that you can get a tablet or android head unit and run a scanning program on it. If both of you have navigation that might be a downgrade but I have no screen.Whole thing is a blank canvas if I want it to be.

 

ok, 250 miles later, CEL still off so apparently the new thermostat fixed the heating issue.

 

Keep an eye on it for a little while longer, but I think so too. Awesome.