Sorry for the history, but I included it case something there is of any significance.

Several years ago I purchased a relatively low mileage (35,000 miles) 2009 Limited Hybrid. The seller claimed he got the car after it was traded in at a Ford dealership in West Palm Beach. He does some of their detailing at his shop. It was sold to him as a non-runner due to a "bad" HVTB. Since this guy didn't know how to charge it, he had a mechanic install a HVTB from a salvage 08.

The car ran fine, but the HVTB discharged quickly...in a few days.

I purchased an '09 parts FEH with 99K miles. It was totaled when something fell on it and crushed the roof. Nothing in the drivetrain was damaged. The HVTB in this car was discharged from sitting after the accident. I built the guy a charger, shipped it and a harness along with a link to our jump start thread and he was able to get it running. Made it to my friend's shop in 4 days and they were able to drive it off the transporter. That seller assured me car was fine...no lights or codes prior to accident. I tend to believe him.

HVTB transplant went fine, but persistent P0AA7 code and wrench light. No driveability issues, normal gas mileage, much slower rate of self discharge than the 08 battery. In short, it operates normally but for the wrench light and code. Call it obsessive or whatever, but the wrench light drives crazy. I want it out.

I've seen the service manual excerpt that basically instructs to clear codes and replace the HVTB if the code returns.

I refuse to believe the HVTB is bad by virtue of it throwing a code and triggering the wrench light when everything else is fine

I've read the threads here. IIRC more than one had a P0AA7 code/wrench light after installing the charging cable from the jump start thread.

Has anyone successfully resolved the P0AA7 code short of replacing the HVTB?

Is it possible one or more of the computer modules needs to be updated by the dealer?

Is there a possible installation error in installing the charging cable that anyone found and corrected?

Is it a bad high voltage battery control module? If so, what years' BCMs would be compatible with an '09. Source for good BCMs?

Any other suggestions short of putting black tape over the light or getting counseling?

Thanks in advance for any suggestions.

 

Ha, mine is the same. It drives me nuts but I've given up. Supposedly this is water ingress? Maybe from charging the battery or opening it? I have tried some things including changing the HV safety plug assembly.

What's weird is that on some days it will not have the light come on. Mostly if the car doesn't use the battery to move initially. I also saw it not come on when I loaded the back and parked on an angle. As if something is loose. I re-did where the battery connects to the car so not there.

If I drive without the light and shut the car off it will 100% come back on.

Mine is also missing the latest FW update. I had thought to buy IDS and flash it to see if that helps. I am worried it would make the PCM take the error more seriously and shut the car down or something, however. No change-log for the FW. I also have an 09.

 

I don't believe this is a water ingress issue, there is zero evidence of that. I read the post you are referring to, but I think that was more grasping at straws than based on any actual knowledge.

 

I bought a VCX nano. It came with a patched IDS. The patched version downloads files but crashes. I also found an IDS v105 in a VM. This version can update modules. I flashed the FDIM.

FDIM went from:
to:
The non flashing IDS downloads an update:
Current BCM:
But the VM IDS won't flash this, I think it's newer than the database for IDS 105 or something else.

What are your versions and it's weird that the software date is so old.

 

The code is no more, the wrench light has been extinguished.

I located a Battery Control Module on eBay. Coincidentally, the seller owns a hybrid repair shop on the east coast of Florida, I'm on the west coast. The shop's name is Exclusively Hybrid and it has exceptional reviews. After I received the BCM, I called the owner, Alex, this past Friday. to discuss my situation. He was busy at the time, but called me back within the hour. He was doubtful the replacement BCM would correct my issue, but as I was relaying the history from my original post to him, he stopped me as soon as I mentioned the jumper cable. He asked if I left it in and when I indicated I had, he said that was my problem. I sent him the link to the jump starter thread so he could see and read what we were doing.

Today (Sunday) I went to friend/mechanic's with the new BCM. He installed the harness and helped me build the chargers.. Since the BCM was easier to get to than the fuse block, we swapped that out. Cleared codes, reset the BCM and started the car...P0AA7-60 and wrench light with 5-10 seconds. Next we reinstalled the original BCM and removed the jump starter harness. Cleared codes, reset BCM and....no codes, no lights.

Since some have experienced this issue and others haven't, I'm going to guess without knowing the way the cable is run has an effect...possibly generating or picking up electrical interference. We ran the cable directly on top of the fuse block toward the front of the car and brought it down to exit the case on the right side of the case, a few inches back from the front corner.

I would still like to have the ability to charge the HVTB should the need arise, so I just ordered some heavily shielded cable and ferrite chokes for a new cable to see what happens. I will update here.

My suggestion is if you have the code and wrench light after installing the jumper cable and those things bother you, try rerouting the cable, use shielded cable or eliminate the cable.

 

https://electricvehicleforums.com/fo...tml#post275151