Hello everybody,

I have a 2009 Escape Hybrid with 126k miles. It runs and drives great in town and on short trips. When I get on the interstate and drive 30 minutes/miles or so, the wrench light activates and the P0A7C code is set, its the only code I am getting. I have coolant flow at the bottle and the mecs pump is running(not sure if its weak and dying , flow seems low at the bottle) I took the FEH to ford and had them reprogram the ECM to the latest softwar as per the TSB but it hasn't corrected the issue. We drove an a long cross country trip and it did the SSN once at the 8 hour mark of driving. I shut it off and it restarted and the wrenchlight stayed off until the 30 minute/mile mark again. Kind of stumped as to what to look at next....I did check the head temp sensor and it was clean and corrosion free... is there any other temp sensor on the transaxle that I could look at? Thanks Jay

 

Hi, did you ever nail down the cause? I just had the exact same thing with my 09 Hybrid that started a couple days ago

 

Found this in repairpal if it helps.

OBD II Fault Code

• OBD II P0A7C

OBD-II Code High voltage system may overheat is defined as a Motor Electronics Over Temperature

The Motor Electronics Coolant Temperature Sensor monitors the temperature of the hybrid coolant system. If the coolant temperature gets too hot, the engine control module (PCM) will set code P0A7C.

High voltage system may overheat Symptoms

• High voltage system may overheat

Common Problems That Trigger the P0A7C Code

• Converter failure
• High voltage control module failure
• Hybrid transaxle assembly failure
• Motor electronics coolant temperature sensor failure
  

Using ForScan, you might be able to run a test or use live data to capture the conditions with and without the wrench.

 

I did see that when I googled P0A7C but thanks for posting. I’m leaning toward the electric cooling pump but was just curious if anyone else had the exact same symptoms and what the problem was. It seems from YouTube that’s it’s usually the pump but as listed in repair pal it could be be a few other things.

 

I had wrench light P0A7C this afternoon when drove on highway at 80mph. When I drove it in the evening there was no issue. Were you able to fix yours? Thanks

 

looks like this was resurrected from 9 of 2018 to june of 2019 and then today (aug of 2020);
so dont know if you are still active;
i did not know that there was a tsb concerning reprogramming the ecu.
How much did the dealer charge for that?

 

if you want to know of something common, very very common to fail - coolant temperature sensor.

 

Only happens in the summer.

 

I would check the MECS pump first and foremost. it is pretty easy to tell if it is running or not. You can look in the reservoir and actually see if the coolant is circulating or reach up and put your hand on the pump itself [behind the front bumper cover a little towards the passenger side on NA cars. Like any electric motor it will vibrate a bit when running or you may be able to hear it. Look to see if it is the original Bosch item. You can get a new pump from ford or dorman or several other aftermarket makers for a reasonable amount of money and change it yourself in like .5hrs.

 

I changed the MECS pump on mine after I got the same code. This didn't change anything for me. I still get the code after driving in hot weather for more than 1 hour. Doesn't seem to cause any problems since mine has been doing this for years. I've had it checked out by a few mechanics and they were unable to determine the problem.

Never had any problems when driving it on local routes under 1 hour.