Check engine light on after tranmission stuck in fourth (4th) gear

24703 Views 12 Replies 6 Participants Last post by ramcares, 1 mo ago

Nykiforuk

Discussion Starter · Aug 5, 2014

Took a road trip last long weekend and when pulling into destination, the truck limped forward after stopping to turn off interstate. Noticed the transmission was stuck in 4th gear and check engine light on. Thought I accidently had bumped it but could not manaully down- or up-shift back to automatic. Knowing my truck and the "ghost-in-machine" electronic system, pulled over to shut off and restart. To no avail the truck remained in 4th gear. Went to hotel and started digging around the forum. Turns out to be a somewhat common problem so tried all the suggestions including re-flashing (pulled M33 fuse (PCM fuse) and turned on and off, pulled battery cable to reset, etc) thinking it must be an electrical malfunction because nothing else made sense (noise, problems beforehand, etc). This did nothing, so drove back home and called dealer to make an appointment. Truck has just over 100,000 kms so warranty off. Possible causes may be solenoid switch board inside transmission, PCM shorted or shorting out, among other issues. Not sure if there are any other potential problems (anyone can offer) but will keep forum posted on developments after taking in and hopefully finding out what the problem was....
Cheers
CN

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TransEngineer

· #2 · Aug 6, 2014

Do you have the fault code(s) that is/are set? That is key to diagnosing the root cause. Likely a wiring problem (broken wire or bad connection), but you need the fault code to tell WHICH wire / circuit / sensor is bad.

Good news: Odds are, the problem is NOT inside the transmission. And even if it is, it would usually be a solenoid problem (easy fix, without removing the trans).

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TransEngineer

· #6 · Mar 7, 2021

What fault code are you getting? P0750?

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TransEngineer

· #8 · 2 mo ago

rittertransportfl said:
I'm having the same issue. I hook up reader code device and my code is P0871... I erase code, let truck sit about 10 minutes then drive on.... it fixes itself. Mine issue always occurs when I have tow/haul button on and the engine brake... but I've had just tow haul button on only and it will do it. Any help I am grateful to accept.

What model year / engine do you have, and how many miles?
Also, when does the P0871 fault typically set? At low speeds, or when cruising at highway speeds? And only when hot?

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TransEngineer

· #10 · 2 mo ago

Richard66 said:
If you mean that there is no fifth gear while in tow/haul mode, then that is by design. 5th gear is eliminated in tow/haul mode to make towing easier on the engine and transmission by changing the shift points on the remaining 4 gears. If you are getting P0871 code, there is a separate problem, which has nothing to do with tow/haul.

I think he (and this thread) are referring to being in full limp-in (in his case, due to the P0871).
"Stuck in 4th gear" is different from "won't shift past 4th gear."

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TransEngineer

· #12 · 2 mo ago

Richard66 said:
Its a little hard to tell the way the post was worded. More information would provide clarity, especially since the original thread never mentioned tow/haul.

Yes, I agree. Posts are not always clear, and sometimes lack pertinent info.
I'm just assuming that since he said "I'm having the same issue," and the title of the thread is "Check engine light on after transmission stuck in 4th gear," that this was his situation also.

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