Limp mode 2010 FF hybrid- code P1AOC?

[proffitt25]

Maybe someone could advise. Recently wife was driving, car went to limp mode. She was driving to a friend’s house on a hill and couldn’t get up the hill. Just parked. I rescued her later, except of course it wasn’t necessary. Car drove fine on the way home and a few other small trips in following week. 
took it to dealership. No warning lights on the car mind you and I plugged in my OBDII sensor and found no error codes. 
dealership says they found P1AOC, want to replace a vapor canister, master control valve (purge valve)- mention it’s tsb 12-3-19. $1200 ($200 diagnostic is already sunk but won’t add to that $1200). 
But, why did they find error code when I didn’t? 
when I look up this TSB, I seem to find that the check engine light should have been on, but it wasn’t. Since that issue, there’s been no other indication of anything wrong. 
I briefly considered trying to replace these parts on my own, but I can’t find much of tutorials on these specific fixes for the hybrid, and if I have to get into high voltage situations, I think I’m out. 
what are the odds that this even addresses whatever issue my wife experienced?

I should add that in 2016 the same thing happened and something with throttle body or an O2 sensor was replaced at the dealer, which did fix that situation. 
ideas?

[Automate]

What software did you use with your OBDII module?  I would suggest FORScan.org

 

When I search "P1AOC" I see:

• Faulty Hybrid Powertrain Control Module
• Hybrid Powertrain Control Module harness is open or shorted
• Hybrid Powertrain Control Module circuit poor electrical connection

Read more: https://www.autocodes.com/p1a0c_ford.html

 

Nothing about the vapor canister except in the TSB but it mentions some other codes that should show up

 

Edited January 26, 2021 by Automate

[lolder]

The dealer is ripping you off, as usual. It's likely the throttle body stuck again. Was it replaced before and did you see the old part? I know it's difficult to check dealer work. They are about $200 and easy to replace yourself. They can also be cleaned with something like a wooden tongue depressor.

 

When Mark Twain said America has no native criminal class, except Congress when in session, that was before automobile dealers.

Edited January 26, 2021 by lolder

[proffitt25]

Thanks for responding!

I have used Forscan before, but right now I'm using a wifi dongle OBD2 and "OBD Fusion" app on my iPhone. I used forscan before to do the battery reset thing, but I thought as far as just reading trouble codes, I should have no problem seeing these using this app. I *think* I'd been able to see other error codes before.

 

Yeah, it's a little confusing, the whole thing. On the page you linked, this is also where I found the link to the TSB: https://www.autocodes.com/pdfview.php?pdflink=https://www.autocodes.com/uploads/ford/12-03-19.pdf&titulo=Ford Factory Service Bulletin OBDII Code P1A0C

That's what Ford is following, and that's what says to replace the canister *IF* there are signs of liquid fuel exiting the canister. 

Then it says to perform a leak test as in WSM 303-13 (I google this and found a manual related to 2011 Ford Mustang, not sure how well that info applies to my Fusion), and if yes, replace the underwood purge valve. 

 

But what I'm not really finding is any indication that these faults would cause a limp-home mode. My general understanding is these aren't really major safety issues, especially not to the extent the engine needs to go safety mode to prevent something real bad. I see people in this forum saying there's a problem with their canister but basically it isn't worth fixing.

 

Separately, non-hybrid, you can find youtube videos of people replacing the purge valve as a first thing to check on various models-- when the check engine light is on. again, my check engine light wasn't even on. I don't really think the hybrid makes that job any more difficult, and if not, I should definitely do that part myself and save $. The canister sounds more difficult/messy perhaps, but I think even less likely to be made more difficult because of it being a hybrid.

 

But bottom line I'm getting pretty tempted to take my car back and think on this.

[proffitt25]

Iolder, thanks for your reply also. No, I didn't see that old part, and unfortunately my notebook showing me cost of work is with the vehicle at the dealer at present. I assume, that having happened 4.5 years ago and no repeat behavior until now, that accomplished its goal and was truly done...

 

The sad thing is the very local dealer p-ed me off a few years back, and now I'm driving it further to go to another dealer. I wish I could find a good reputable hybrid-certified mechanic, but I feel like there are some things I just have to go to a ford dealer for. 

 

It's also really difficult in my mind to do the "show me the used part" thing. It's just saying quite out loud "I don't really trust you". Maybe that's justified, but it sure sucks.

 

 

[proffitt25]

I decided to get my car from the shop, pay the $200 diagnostic, and see what I could do on my own. 
 

gonna try FORScan— I see there’s an iOS FORScan Lite now. I got the viewer free version first to see what it could see, and it couldn’t read from the PCM. If I pay to download this version do we think I’ll have the same problem and need the windows version? Or is there other reason to assume I may want the windows version and should just skip the iOS? Unfortunately harder to find a windows PC around here these days...

 

the dealer did claim that they took off the canister and tested and found evidence of fuel leak there. I drove from dealer to emissions testing and passed just fine. He also claimed that the system detects fuel leak and goes nuclear with the limp home mode. Still seems to me no reason that an issue with the evap canister/purge valve etc should do any more than throw a check engine light. 
 

once I see if I can find this stored code (that’s what the dealer says it is, not an active code, thus why I didn’t see it with my OBD2 tool and my OBD fusion app), then I’ll decide whether to look into the evap stuff at all or pursue throttle body stuff.  

[Automate]

As far as reading from the modules the Lite versions of FORScan can read everything the full version can.  The difference is the Windows version can write to modules to change settings and to put the modules into self test / diagnostic test modes.  The dealer could have cleared all the fault codes from the modules so there is no guarantee they are still stored in the modules.

 

[proffitt25]

Okay, I downloaded Forscan Lite for iOS and ran it, worked fine, found the P1AOC code- hybrid powertrain control module- engine disabled

status: previously set DTC - not present at time of request

-MIL is off for this DTC.

 

So at least this matches with what dealer found, and would seem to be the cause of my engine failure? Still doesn't seem like it should to me. 

Now the question is whether to try and follow the TSB and test things myself, see if I can fix them myself, or maybe take to another mechanic that I like.

 

There's also the wait and see if it happens again approach...

[Automate]

You also need to consider the other things besides the TSB that are suggested for repairing P1AOC

 

"Visually inspect the related wiring harness and connectors. Check for damaged components and look for broken, bent, pushed out, or corroded connector's pins"

 

[proffitt25]

That sounds easier than other potential fixes. 

[lolder]

The throttle bodies on the FFH are known to soot up and stick are the most common cause of limp mode.

[Automate]

This is for an 2008 Escape Hybrid but its the same fault code and turned out to be the throttle valve https://mechanics.stackexchange.com/questions/41809/2008-ford-escape-hybrid-stop-safely-now-p1a0c

 

Here is one that ended up being the purge valve 

 

 

 

Edited January 30, 2021 by Automate

[proffitt25]

Awesome guys! Thanks for the links and other options. it's nice to have another vehicle so I don't have to depend on this one-- and again, in the times I've driven it, I've had no problems since. But the wife is avoiding it mostly for now. 

Anyway, particularly interested in trying the free fixes, and I'll be watching some videos!

[proffitt25]

I do wonder if the dealership truly checked the evap canister and found fuel leaking around it. I'll have to dig around and decide whether I want to perform that check myself too, because even if, say, I go in and clean the throttle body, I'm not going to be sure for quite a while whether the evap system is also a problem that might cause a repeat. Of course it's just harder to troubleshoot something if you can't easily repeat the behavior, for all I know it's "fixed itself" already.

[proffitt25]

It seems like the throttle body might actually be easier to get to on this hybrid than in the non-hybrids shown in most YouTube videos. I didn’t pull it off yet, but I pulled off the hose so I could get to it. The “flap” didn’t seem to move super easily to me (using a popsicle stick), but the part looked pretty clean, at least on that side. Even if it doesn’t look too difficult, I don’t want to get the part off and then decide to drive somewhere to get the cleaner. Though, maybe I should, I could take another vehicle to get it. 
 

I didn’t fiddle with it long but I couldn’t quickly get whatever electrical connector off of the throttle body. Sure I can figure it out with some effort, especially after I take the throttle body off. 

[proffitt25]

Before and after. Not too bad. 
 

I followed a guide for recalibrating idle trim with hybrid- put it in park, gas, to neutral, let it idle one minute, put it in park. Then drive 10 miles. 
I see other guides for non-hybrids with like shorting the battery to reset pcm and all. 
 

anyway it seems to drive well, sure looks a lot cleaner. I’ll report back if there’s an update. 

[proffitt25]

Actually just to add that wasn’t the final after pic. I kept cleaning and got 99% of surface shiny. 

[lolder]

Nice job!