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2018 L5P sudden loss of power and shut off

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Coming home from a four-hour trip Sunday towing a small utility trailer, my truck dropped to idle while at speed on the interstate just a few miles from home.  I was lucky and able to pull over to an exit ramp with zero power.  While coasting the display popped up saying reduced power for a couple of seconds and the engine light came on. While still on the exit, all power restored, message went away, and I was able to make it home on back roads. 

While it was still running I pulled three codes: P0087, P129F and P228B.  Cut it off, unloaded everything and then went to move the trailer.  It turned over for a few seconds then busted off (longer than normal).  As soon as I put it in gear it shut off.

Got it to the dealership and awaiting the results.  Truck only has 1,404 miles on it and was delivered from Flint a few weeks ago.  All displays read fine, fuel filter, DEF fluid, etc.  Engine light still on.

Just FYI to add to the list of L5P problems

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P0087 is Fuel Rail/System Pressure - Too Low, indicating a fuel system problem.

P129F – Fuel pump speed signal -incorrect

P228B - Fuel Pressure Regulator 2 Forced Engine Shutdown




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  • 1 month later...

They replaced the lift pump and fuel filter and said all was fine.  It hasn’t shut off or stumbled again but I haven’t towed anything either.  It has a few times taken a few seconds more to bust off when cranking, but no codes.  2800 miles on it now.  At least the steering still works on this one!

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  • 3 months later...
  • 3 weeks later...

These poor diesels, they have just killed them. The diesel used to be as dependable as an anvil, not so much anymore.... Sorry for all of everyone's problems, seems a class action suite might be in order, 82 thousand dollar unreliable truck, bummer.

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  • 2 years later...


Ran a 2018 L5P for 3 years with zero issues.



2017, 2018 and 2019 L5P were 'old' body style and used the 2011 thru 2019 chassis

2020 and 2021 L5P is in front of the new 10 speed transmission.  Body and chassis are all new.  Cooling system is significantly bigger. Fan is bigger diameter and fan drive is now it's own belt, separate from rest of accessories.

Banks has a youtube showing side-by-side L5P for 2020+ and  '17-19,  reviewing/discussing the changes .


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