Afternoon all,

So my 2015 F150 had been throwing the wrench light on here and there and my auto stop/start quits working. It only seems to do it when I first start the truck and don't drive it very far initially. I read some of the threads about it here in the forum and got a lot of information about it. Just got Forscan on my laptop and an OBD2 cord to use. From what I'm reading, my auxillary transmission pump is the problem. I have mixed feelings about auto stop/start. I get the point of it but I'm not sold it helps make a huge difference in fuel economy. Anyway, I'd like to disable it altogether but using Forscan is a bit daunting. Anyone have step by step instructions? I don't want to screw up any programming in my truck. I'm used to the old simple code scanner. Thanks in advance.

 

Honestly man, you can disable AS/S for good and for free if you’re comfortable popping the switch out of the dash. There’s a few old threads around about a jumper wire used to short the switch. Essentially your “off” button is permanently pressed unless you undo the wire. I did this over 10k miles ago and have had zero issues. (Some have even wired in a toggle to their glovebox) Doesn’t effect any other systems like forscan or unplugging harnesses would. There’s a few modules that you could buy if you want to continue to turn it on/off, but if you just want it off, I say jumper it. Takes 15mins tops and cost literally nothing if you have a piece of wire laying around in a junk drawer.

 

I think I can handle that. 😆 Appreciate it. I'll check it out.

 

I think step one should be troubleshooting why you have a wrench light.

Auto start/stop is being disabled because of the trouble code. Many prefer not to use the system, that's fine. But disabling it will not make your wrench problem disappear, most likely.
It will make you feel good though as a users who doesn't like the technology bit here.

You can also find on Amazon an electrical harness to plug in that disables A.S.S. Or you can get a trailer connection cord thingy and leave it plugged in....when the truck thinks a trailer is connected, A.S.S. is disabled.

It is possible you need to charge your battery -I'm not aware that a low battery situation will throw a wrench at you though.

 

I did troubleshoot. By using Forscan, I pulled code P0C27 for the auxillary transmission pump. I read on multiple threads about this pump causing issues. Like I mentioned earlier, the wrench would show up after my initial start up and if I didn't properly warm up or I drive it for a significant amount of time before the auto stop/start kicked in, the truck would start back up automatically and light the wrench up on the dash. I works continue driving with no issues and if I stopped, shut the truck off, and restarted it, everything would return back to normal and I would have no issues at all. It's just that initial start up timeframe. The fluid and filter in the transmission has been changed so that's not an issue. I just installed the jumper wire so I'll give that a shot. If it returns, no harm. Back to square one.

 

The hint is in what you did do see the issue.
Starting the truck initially is one thing, driving a short distance and having auto start fail is the hint.
The battery is likely aged enough and won't get recharged enough in that short distance.
If the voltage is low, auto start will be inhibited because many electrical functions depend on power to work above a min. voltage.
Ie, trans pump, low pressure fuel pump, the rest of the power needs etc.
If you check battery voltage before starting, then after failure you may see the cause.
Don't blame it on any thing else because the system was designed to do this.
When power/battery gets low enough in traffic, you will have it happen there as well.
Even manual start will fail if battery condition gets down.
May be time to replace the battery if it is 6 years old or the charge system has a fault or both

 

I have yet to replace the battery and I was curious if the age of the battery was a contributing factor to this problem. This whole battery monitoring system thing is new to me. First vehicle I've ever had with it along with the auto stop start feature. I wasn't sure if the auxiliary trans pump was electronically controlled or mechanically controlled. If it is electronic like it sounds like you're insinuating, then yes. It may be a good time to replace the battery now.

 

Realize, your auto SS is not going to work when you first start up the truck and for a while yet until the engine and transmission have come up to temperature among other things. I'm not sure how you're relating the auto SS to the other problem. You can simply disable auto SS with the switch on the dash to see if that makes a difference. Your problem appears to be a start up problem only which apparently happens with both initial startup along with the startup that takes place with the auto SS. Disabling auto SS isn't resolving problem. I agree with the potential need for a new battery that is known to cause weird unexplained problems.

 

Would usually happens is that I'll get in my truck first thing in the morning started up and everything is fine. The starter doesn't lag or there's nothing that gives me any sort of an idea that there's a problem with the vehicle starting. I make a right out of my driveway and go down the road to the stop light which is exactly one mile down the road. If I get caught by the light the auto stop start kicks on and the vehicle shuts off. After about 2 or 3 seconds it starts back up and the wrench symbol appears on the screen. According to the owner's manual it says it's a drivetrain problem if you look it up. I recently downloaded for scan on my laptop and got the appropriate OBD2 cord to use and when it happened today, I hooked up my laptop and it gave me that particular code that has to do with the auxiliary transmission pump. After doing some reading on other threads and how issues with that pump were causing problems with the auto stop start feature on other people's trucks, I could only assume that it was the culprit for my own as well. I've went into town and after the code has flashed at the light, I'll go to the gas station and shut the truck off and get gas. I'll hop back in it it starts up fine and I never have another issue with it. Auto stop start works well and the wrench symbol never shows up again on my dash throughout the rest of the day. Maybe it is a battery issue. I noticed over the last winter that rather than the auto stops start working as usual, my truck would stay running and I would get the message engine on vehicle charging until after I had driven it a while. That kind of led me to believe that the battery was aging but yet auto stop starts still with work after I driven the vehicle for a while so I wasn't too concerned. I think the next step is for me to replace the battery and maybe pull out the jumper that I just put in and see if the problem is corrected. I'm not sure if I want to let the truck sit for 8 to 10 hours and let it relearn the condition of the battery or go in and reset it in the computer. I guess I'll figure that out once I get the battery

 

If you are on the original battery, I highly encourage replacement. I see (disappointing), many people getting 2-3 years tops. When they go bad all sorts of goofy electronic things happen. I do have the AutoStop eliminator as I was not a fan as you, but I think your issues and even possibly your transmission code can come from a bad battery and the ripple effects. I certainly would start with a load test at a local Autozone.