Question

[countrycorey]

Yesterday morning, got a call from my dad that his truck wouldn't start (2018 L5P) when he got off work. He told me over the phone that it was turning over but that it didn't seem like it was getting any Fuel. No big deal as I'm on the other side of the plant working nights with him. I pull up and tell him to try and start it and it fires right up but now has a check engine light on. I grabbed my V2 and pulled the code and I got code P129F, Fuel pump speed signal incorrect.

Initially, I thought possibly an air leak or cracked filter housing allowing the system to lose prime. Anyone have any input as to what to look for/at or what needs to be done?

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[Cougar281]

A quick Google for the code suggests that the lift pump may have died.

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[countrycorey]

A quick Google for the code suggests that the lift pump may have died.

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I thought that too, but he was able to drive it home this morning and back in to work again this evening with no issue, so not sure about that just yet

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[juddski88]

The fuel pump control module is a somewhat common problem point, as is the harness and connector to the module, particularly in dirty and wet environments.

 

[Cougar281]

There is also this bulletin, but it references 2019-2020, not 2018:

https://static.nhtsa.gov/odi/tsbs/2021/MC-10198865-9999.pdf

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[juddski88]

There is also this bulletin, but it references 2019-2020, not 2018:

https://static.nhtsa.gov/odi/tsbs/2021/MC-10198865-9999.pdf

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Gm's way of cheaping out. Becoming all too common. As much as I love the l5p/6sp drivetrain, the rest of the truck can and will rot in hell.

 

[countrycorey]

Gm's way of cheaping out. Becoming all too common. As much as I love the l5p/6sp drivetrain, the rest of the truck can and will rot in hell.

Thank yall for the input and what to look into

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[countrycorey]

Dad ended up having to replace the Fuel Control Module and said it drives like a different truck now.

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