I'm no expert but I seriously doubt that 5 miles per day morning and evening are enough to keep the HV battery tended and adequately charged. This is especially true if it is cold (below 50 degrees or so) where you are. The car isn't getting much in the way of regenerative braking and because the battery isn't up to temperature, the motor/generator in the transaxle will not do its usual job keeping the HV battery fully charged. You need to drive it longer distances every few days and get it fully warmed up if possible, because it is the only "normal" way the battery is maintained and recharged.

Even though I keep my super-short trips to a minimum, I never let my '10 FEH Limited sit longer than 72 hours if I can help it. I don't even have the jump start button!

As SKeith says, short trips are murder on the battery and short, cold trips with a prompt shut-off and cool down are even worse. They're really not good for any car - and the Hybrid has concerns of its own as well.

 

Hi All,

This thread is a tremendous resource for the FEH. I purchased 2009 at an auction recently and followed the instructions to get my hybrid battery back to a workable charge. 4+ hours charging and it reads around 340 volts. The vestigial wires were easy to hook up to the homemade charger (Thanks, S Keith).

The low charge code went away after charging but I’m left with code P0A0A High Voltage system Interlock Circuit and related codes about the hybrid drivetrain disabled. P0A0A shows up in the PCM and the BCM on Forscan. When I clear the code from one it comes back and I can’t actually start the vehicle. I’ve read this could be the wiring harness or any of the high voltage wires. What can I check to troubleshoot this particular code?


12V battery is charged, I’ve hooked the cables back up the the high voltage pack and the service plug is locked in. I do have a front and rear inertia switch but pressing those didn’t help. Is it possible I didn’t tighten the nuts under the seat enough and it can tell?

Thanks in advance for all the help and expertise.

 

Sounds like a safety plug that's not properly installed. Double check the safety plug. Pull it and ohm the two pins.

Did you remove the main orange cable? If so, is it installed correctly?

As long as you have most of the bolt's properly tightened, I wouldn't expect you to have an issue.

 

I verified all the connections including the orange cable installed correctly and tested the safety plug, minimal resistance across those pins. It was 1.5 with multimeter set to 200, same as when I touch the probes together. I am still receiving the P0A0A code which disabled the hybrid powertrain. I also have a tire pressure sensor code but I wouldn't think that would affect the high voltage system. The red security icon lights up when I turn the ignition on and the ignition has a hard time knowing when I remove the key, an issue I believe is common on the escape.

I dug a little more into Forscan and found that the BSOC% is showing 0% even after I charged it for 4 hours. Thinking maybe the cold (AVG_TEMP 52) or the length the battery sat (7 months) made the chemistry go dormant I charged it some more hoping to bring the SOC up. That didn't affect the SOC but now the HVB volts are around 350. I tired to find any other helpful readings, BATPAC_STAT Pack OK, DEL_MOD_V 0.06, HEV_VEHSTAT BPO, and of course the High Voltage Interlock is Open.

EDIT: I saw the a post from S Keith in another thread saying "SoC is CALCULATED based on voltage, temperature and current." So I deduce if my interlock is open there would be no current and therefore SOC would still show 0%. I'm back to visually inspecting the orange high voltage wires to deduce why my interlock is staying open.

EDIT EDIT: I checked with Forscan again today and I do have readings for BSOC. There was a range but the current SOC was hanging around 7%. Voltage went down slightly to 345.

I really hope this is user error and I'm missing something simple. What else can I check in Forscan or physically to get to the bottom of this?

Codes
P1000:00-2B
P1A10:00-2B
P1A14:00-2B
P0A0A-FF
P0A0A-60

 

Everything is pointing to the safety interlock switch. Either the switch itself or the wiring to the front of the pack where it connects to the orange main harness. IIRC, the small contacts on that plug are the interlock circuit..

4 hours is enough charge to "reactivate" "dormant" cells. BSOC is expected to be 0% or low as accurate SoC can't be made until the car evaluates voltage response to current at a given temperature.

 

I resolved my issue with the high voltage interlock. A huge thank you to S Keith for pointing me in the right direction.

The high voltage cable that comes out the rear of the battery pack has two small wires on top, these are 12V wires and are part of the interlock circuit. As far as I can tell this is the only segment of wire that has the 12V wires on the outside. The function of the interlock is to verify all the high voltage cables are properly installed. If any of the cables are removed the interlock circuit shows up as open and disables the hybrid system. Having verified all my connections I decided to connect these small wires to try and trick the interlock system. I added a wire between them and otherwise left the circuit intact. When I read Forscan afterwards the high voltage interlock circuit says closed. I cleared the codes and my escape started right up for the first time since I've had it. The BCM interlock code is gone but notably I still have a persistent interlock code on the TCM.

I hope this helps if anyone ever has a similar issue. Thank you to all those who've come before me for their knowledge, especially with the vestigial wires to connect my charger.

 

Did the wires get cut?

 

There was no damage to the wires, high voltage or interlock, anywhere I could observe. Then I did physically cut the small wires shortly after they come out of the battery pack to add a wire between the two. I read about this method of tricking or bypassing the interlock circuit on a ford fusion hybrid forum and it worked for my Escape.

 

Ah. You likely damaged the interlock circuit somewhere inside the battery. You figured out how to bypass the circuit. Just understand that the safety plug interlock switch is disabled.

 

And be sure to let the next owner(s) know as well as anyone ever working on the car.