P061B - 4lo manual downshift from 2 to 1

[UpInTheAir]

I wanted to use 4lo to engine brake down a steep dirt road entirely covered in snow and ice yesterday. Barely rolling maybe 2mph with no throttle in 4lo, I manually downshifted from 2nd to 1st, and the truck lurched. The dash lit up with the wrench icon and pre-collision disabled. I tried shutting it off and restarting, but it was still in limp mode. Once I made it home, I managed to pull the P061B code and found the following thread on the BRaptor forum, specifically post 6, reflecting the exact issue I encountered https://www.broncoraptor.com/threads/obd-ii-fault-code-p061b-limp-mode.1587/. I went back out to start the truck maybe 10 minutes later, and wouldn't you know, the truck was out of limp mode with no CEL/wrench light.

Looks like Ford hasn't fixed their programming after knowing about this for at least a couple years now so I am not going to waste my time going to the dealer. Wanted to post it here in case anyone else encounters it in the sticks. I use engine braking frequently on steep, loose forest service roads in my other rigs so I expect it'll rear its head again in the future if I take the RRaptor out.

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[Wayfaring Ranger]

I wouldn't ever downshift into 1st unless you're completely stopped.

 

[stuartmunto]

Yeah as previous comment - never downshift into 1st manually while moving. You should have left it in 4L (auto) and use hill decent control - set your desired speed and let the truck take care of it all. The tools and tech is there, why not use it. You can do serious damage to the drive train when in 4L by doing something like forcing it into a gear it shouldn’t be in

So yeah, I would say this is not a bug at all, it’s an error code that potentially saved you from doing serious damage to the drive train by putting the truck into limp mode

 

[ilDiavel]

The 4L shifting logic is absolutely awful. The team at RangerAssault school said Ford was looking at it, and were going to update it, since they deal with the problem a lot..... but I wouldn't hold my breath.

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