Hi All,

My 2009FEH has about 165K miles on it and runs pretty well other than a wrench light that comes on after about 20-50 miles depending on outside conditions for Motor electronics over temperature P0A7C. About a year ago I replaced the MECS pump with a genuine motorcraft pump (~$350) and it didn't fully resolve this issue. Seemed to take longer trips to cause the code to be pulled (about 70-100 miles) unless I was running AC and temperature was really hot outside. Car never shuts off or anything and doesn't seem to affect driving.

I've checked the pump and it feels and sounds like it is running, I can feel the vibrations in the line by the pump but once I get to the coolant tank it is pretty hard to tell if it is running or not. I'm assuming it is not functioning well. Has anyone else had this issue in a 2009? I'm apprehensive to buy another MECS pump since the last one didn't fully resolve the issue either. Anyone have any advice?

Thank you!

 

Not sure if it's an issue with the Ford, but on the Prius, the inverter cooling passages can get plugged with residue and compromise cooling. Air in the system can also prevent circulation/cooling.

 

Thanks for your response. That is interesting, so if that's the case I can potentially try to take the lines off and clean them out.

 

It's purely speculative. It required inverter removal and disassembly. Found it:

https://techno-fandom.org/~hobbit/cars/ginv/i1mech.html

Scroll down near the bottom.

 

terrible engineering not to have a temperature gauge; problem is if you design one guage then you must also design another temp gauge.
years ago i had an 88 honda civic and it it was hot and i turned on the ac, the temp gauge started a rise into uncomfortable territory.
left it go - just could not figure it out. i could cut off the ac and or just let up on the acceleration and the temp would drop back to about normal.
weird; one day i was hosing off the radiator and just happened to run my hand over the area of the plastic tank and there was an unusual happening;
bubbles appeared at the site of a tiny crack of the plastic part of the radiator. SO, there was the problem - Not holding the pressure that it was suppose
to.
the tank is an expansion tank rather than a reservior. an expansion tank is part of the pressurized system and it could also have a tiny crank and thus you
are not holding the required pressure (the holding tank is an expansion tank it there is not a cap on the radiator - which is the case that i have (and i have
an 09 ford escape hybrid limited))
i would take some soapy water and spray the top of the radiator (plastic part) and feel for a tiny leak and the same for the expansion tank. And not a costly option
to try. also i would have replaced the cap before the electric pump (cap is much cheaper than the pump)
this is my first hybrid and i wished when i saw everything that i did, that the engineers would have designed it with only One cooling system instead of the 2 separate
systems.
But there needs to be a temp gauge for the gas engine system and i thought about designing one but just got too much to do (at this time).

 

Ford Tech Makuloko has a video about replacing the MECS pump and it's interesting to note that when he refills the system, he uses a vacuum bleeder and shows how to purge/bleed the system. It looks with all the lines and components there are a lot of places for air voids to get trapped. And even with the vacuum bleeder, he recommends checking the system level for a couple of days afterward because of the possibility of remaining air voids, so it's kind of tricky to purge and bleed this thing completely.

He also shows how to check if the pump is running, etc., and mentions the coolant: 50/50 mix of water (I would use distilled) and the Ford "gold" coolant (Ford Fluid VC-7-B Gold Concentrated Antifreeze/Coolant).

Maybe you have a bad cap on the reservoir, not holding pressure? Air in the system? He doesn't show your specific code.

 

Thanks for the insights. This is the video I used to change the MECS pump in the first place, it was really helpful. One thing that was different is he mentioned there is a bleeder valve you can do if you don't have the vacuum pump to remove bubbles. I have a 2009 and I can't seem to find it. It seems the area where it is supposed to be is much more crowded in the 2009 than the 2008 I think he is working on. I will do some more work to see if I can check that system to see if I can more properly remove air.

 

Thanks for the details. I am going to try the method you mentioned to see if there are any leaks in the system.

 

I was able to locate the bleeder socket (12mm) and I ran the coolant system for a few minutes with that socket unscrewed until the system leaked some coolant as instructed by the factory service manual. I then tightened it up. The coolant level did not change very much so I am not sure it had too much effect but I will test it during my commute tomorrow.

I also checked around the system for leaks with soapy water but was unable to find any.

 

If you didn't immediately get coolant out the bleeder, then there was air in the system. Any air in the system will compromise cooling. Hopefully, you have found and resolved the issue.