Hi, new member here, long time mechanic, first time hybrid owner.

I just got this 07 FEH 4x4 a few days ago. It's got 141k miles on it. I'm getting rotten gas millage. 11mpg!

The first day I was driving it, it wouldn't go into EV mode at all. Though it does work in assist. I've since replaced the HV battery air filter. The ac wasn't working when I got it either. I've put Freon in it, and it's holding about 32lbs pressure on the low side. The air blows cold, the line going to the HV evaporator is "beer can cold".

It's going into EV mode now, but rarely will it stay on in acceleration, and never much above 20mph. It's idling above 1000rpm (not sure if that's normal). I pulled the duct out of the cargo bay and verified the fans are working in the battery. The recirculate door is functioning also.

I pulled the beauty cover off the engine. It appears nothing has been serviced recently, everything has typical dirt on it. I'm gonna try throwing new plugs in it, and replace the fuel filter. Probably clean the MAF too. I checked the coolant levels in both reservoirs, looks fine, and clean.

I scanned it with an OBDII scanner. No codes of any kind for a typical scan, though I don't have a Ford specialized scanner to check the BCM.

Anyone have any advice or suggestions? I hope the HV battery isn't at fault here, but I'm worried.

 

A/C failure is the fastest way to destroy a HV battery.

A hot battery will barely work for anything but starting the engine.

The EV behavior you describe is normal. These are not EVs. They are gas cars with HEV assist.

There are two battery fans. Pulling the duct only confirms that at least one is working.

Most "wrench" codes are hidden from standard OBDII. Get Forscan.

Continue your pursuit of "tune-up" type items and reassess overall performance. Also check for dragging brakes, etc.

 

After swapping out for new plugs, the mileage actually got worse. Like I said, the ac system is functioning now, though it was not when I got the vehicle.

Do "wrench" codes all show the wrench mil? I have no lights on on the dash at all, though they're all live for bulb check.

I downloaded Forscan, I was thinking about that anyhow. Looks like a really useful tool. I'm waiting for the sync adapter, should be here Thursday.

I had read somewhere, that Ford built a time based limp mode into these where after 9 years they basically stop functioning as normal, and only put minimal loads on the battery. To your knowledge, is that something I can recalibrate in Forscan, or will I require additional licence and service packs for the software?

I shouldn't get too far ahead of myself. I opened the software, but don't have a great idea yet of what it'll do once synced. Hopefully I'll get a better idea of what's going on here. Thanks for your interest. I'll update back when I have something to report.

 

Struggling to get better than the gas FEH is one thing, but 11mpg is another. Seems unlikely the HV battery is the cause given your description of the EV operation.

Wrench codes illuminate the wrench light.

I don't recall the process on "resetting" the hybrid battery age via Forscan. I think it takes the registered version.

With forscan, you'll be able to do deep diagnostic dives and look at various data from the BCM, ECM etc.

 

Yeah, 11mpg is completely unacceptable and there must be something wrong. It's so strange. No lights, drives just fine. I can watch the hybrid system go through all its modes on the nav screen.

I would think a serious mechanical issue in the engine or trans causing this bad of mpg would also be a drivabilty issue. But it runs and drives great.

I had only taken it on a short test drive before bringing it home. I didn't know how to work the nav screen or monitor mpgs, or I might have left it where I found it.

If I've gotta shell out for the license, I guess that's what it is. I'm sure it's cheaper than a Snap-on scanner. At least for now I can pull up the stats on the battery and see what's going on.

 

Have you verified mpg with a fill and distance calculation, or are you relying on the mpg result?

 

Going mostly off the mpg result. I didn't fill the tank when I got it, just threw 20 bucks in it. I set the trip tonight though. The dash says I'm 220 miles to empty, and I'm going to compare them.

I do wonder if the mileage calculator onboard is accurate. The nav radio is pretty beat up. The screen doesn't display properly, but I can make out most of what it says. It seems to have a short in it somewhere. The CD player isn't working quite right either. I can hear the short in the speakers, if that makes sense. I'm gonna toss my pioneer unit in there sooner than later, but I wanna figure this out first.

I would assume it's just displaying what comes from the BCM, but that's just an assumption.

 

Well I pulled the dtcs, came up with a POA81-60, battery cooling circuit. I can't see anything in Forscan to run a more detailed test though. I'm assuming one of the fans is bad, but I'd like to test further. I'm gonna dig around on the Foracan web page and see what I can find.

 

I also ran a scope test on a few of the battery functions and took it for a drive. I'm reaching nearly 84% charge capacity. But I'm also hitting 99 degrees temperature and staying there. I'm convinced the fan is causing this. I ordered two of them and will replace both, and see what happens next.

 

What was your evap temperature?