Hello all. I purchased a fixer upper 2010 Mercury Mariner Hybrid 2wd recently. Has 175k on it. I bought it with the previous owner stating it wouldn’t go into overdrive. I knew that wasn’t the case as it has an eCVT. He recently installed new O2 sensors and a new throttle body(aftermarket). I’m keeping my fingers crossed that it isn’t something major.

Here’s what it’s doing as far as I can tell.
Truck starts, electric drive kicks on and then the gas engine kicks on when it senses a load I’m guessing. I can feel the regen breaks working as well. Driving it up to around 45-50mph you wouldn’t think anything is wrong with it. Trying to get above that sees the gas engine screaming to 5k. Have no engine or warning lights on the dash.
Ran Forscan via my windows laptop and got PID P0AFA 16-28. I cleared it and went for a drive. That PID never came back. However I did wind it out a little bit more to get to almost 70. She was screaming. Shortly after that I got the red triangle and to stop safely message along with code P1A0C. Cleared that, turned the car off and on and was able to make it back home.
The Forscan is giving me an endless amount of data, but I’m not on what to do with it all.
What are some readings that I can look at to start eliminating possible issues?

Sorry for being so long
Appreciate any help
Thanks
John

 

Recommend you get a subscription to the tech data:

https://www.motorcraftservice.com

For a very reasonable fee, you'll get a couple of days access to all Ford manuals with applicability by VIN.

What you'll find is that the sole remedy for P1A0C is to replace the hybrid battery pack. It's been alleged that one can replace the battery computer to resolve that. I tried a total of three, and that didn't take care of it for me.

You might be able to completely disassemble the battery and find a lose wire or poor connection somewhere on the 250 cells and related connections.

Good luck.

 

Thanks S. Keith. I’ll definitely be looking into that Ford service info for $22.
When it comes to the P1A0C code can it still indicate a bad battery pack if it’s intermittent and doesn’t come back once cleared?
What about and voltage readings on the system using Forscan? What would I see along with the code to confirm a bad battery pack?
I work for an industrial equipment company and there’s guys In the shop that rebuild and service electric fork lift batteries. Any thoughts on disassembling the battery and replacing the faulty green battery cell sticks?
If I were to look for a used battery pack and tests I can do with it out of the vehicle?

Thanks again for your help
John

 

1. If it doesn't return, it's not an issue.
2. What about it?
3. Not necessarily anything. Drivability issues + P0A1C means the pack has failed somewhere, and it likely won't show any other indication.
4. Not a translatable skill.
5. I wouldn't do it unless I had mountains of spare time. I've had multiple opportunities to do it for money, and I wouldn't even consider it.
6. Not much. Simply use VM probes to carefully pierce the shrink on the sticks at opposite ends to measure voltage. IIRC, you'll pick up 4 cells. You'll want all measurements to be nearly identical, and you want each voltage reading > 4.90V

As far as useful Forscan data, I think it's labeled "DEL_MOD_V" in the BCM stream. If that's > 0.2V, it's a bad sign.

 

Thanks again for the info S.Keith. Looks like I’ve got some stuff to look into and decisions to make.
Will keep the forum updated.
John

 

I wanted to give everyone an update.
After removing and testing the battery and accidentally frying a BCM.
My problem from the beginning was clogged catalytic converters. Not sure which one as I hollowed both of them out.
Truck runs great.
Thanks for all the suggestions 👍
John

 

Shocking that you didn't have a P0420 code.

 

I did the doubling up of the 18mm anti fouler on the downstream O2 sensor. Not sure I like the exhaust fumes especially if I’m going to be hauling dogs with the hatch window open.
Hoping to find the front catalytic converter that doesn’t cost $600-700 😳
John

 

There are likely aftermarket cats for far less. Even if they code, they are vastly better than nothing.

 

Word to the wise. Whenever replacing cats fix what is wrong with the engine first. Make sure because you will be eating another converter within the year. Burnt oil, leaky valves, or misfires will definitely get you there.