This 09 Escape Hybrid only has 90k miles. The battery works fine however the wrench light is on caused by DTC P0AA7 which means Voltage Isolation Sensor Circuit error. Factory manual says replace the battery but I'm trying to save it. Any solution? Thanks in advance!

 

i have only had a hybrid for 3 months (so i am not the best qualified) however off the internet:
"The high voltage system uses a battery voltage isolation sensor inside the battery control module to monitor separation of the high and low voltage systems.
If sensor fails, P0AA7 will set. The high voltage system may become disabled."
i had the battery control module out about a month or so ago - it is behind the relay.
the top plate screws are easy but there are 2 on each side that are very close to the interior side panels;
they are a pain.
i have a write-up on one of my posts of lifting each side of the battery and supporting with small blocks of wood.
i dont know where one would get a BCM though.

 

http://www.bumblebeebatteries.com likely has battery computers available.

 

thanks for the reply. I swapped the BCM with a good one from my other FEH but still have the wrench light no. I guess both BCM are good. I think it might be a broken wire causing this issue. Car runs fine. Just the wrench light bothering me. Can’t ignore. It.

 

Any possibility you have a water leak triggering the code?

 

it looks dry but I'll double check. Thanks

 

Just an update. I replaced the battery with an used battery bought from a junk yard and the P0AA7 disappeared. Now have different issues to deal with

 

Thanks. Please keep us enthusiasts updated so we can keep learning.

 

well to follow up what Hippo has posted: Thanks for the info.
but that brings up a couple of questions:
1) what instrument did you use to ascertain that the hybrid battery that you bought was a good battery? scanguage or just voltage meter
2) dont know if you want to reveal: How much did it cost?

 

I bought the battery from junk yard for $300 cash in AS IS condition. No, i did not know the condition of the junk yard battery. After it's installed, I found two new DTC. One was a broken fan. It replaced it with the fan from my old battery. The 2nd DTC is P1A07. Manual says either it's a broken high voltage cable or a broken transmission. I don't remember if I had the code before. I checked the cable connection again last night but didn't fine issue. It must have something to do with the new battery. I don't know what to do next. Maybe I will pull another battery from junk yard.