U codes?

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billetgrey

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Hi guys. Still tying up loosening ends on my truck post lifter+cam swap. Looking for some advice. Have been to busy able to do anything on it since the last post.

Alongside the MDS solenoid code after making the post the truck put up a whole bunch of u codes at once. They came up right as I unplugged my code scanner, the screen did a little glitch then the CEL flashed. I scanned it and it came up with several codes which start with U.
U0121
U0100
U11BC
U1110

U0140 - this one, for the BCM, truck has had it for years, since being repaired after an accident, never poses a check engine or anyt issue, and it's last on the list, thought I'd still include it though.

I'll put pictures of my scanner screen with the code descriptions.

The truck runs and drives perfectly fine. The CEL flashes when first starting it but doesn't again. All of this is just based off of one drive post cam swap.

I got the parts store to test the battery for me, they said it's in perfect shape, but I'm not so sure since it's been used for 4 summers and 4 brutal winters to start this thing, and sat in my warm barn during the entire summer and last winter without being charged. It was just one of those handheld testers. I'll put those results in a picture too.

Can anyone think of anything I may have missed post cam swap, or something I can check up on? Electrical stuff is not at all what I'm good with really. I did create a new ground for the ground wires that go from the back of the heads. I reused the old ribbon like wire for head to head, then used a new ground cable from one of the heads to the grounding bolt between the battery area and fender. Could that be part of this?
 

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Jim BB

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Hi guys. Still tying up loosening ends on my truck post lifter+cam swap. Looking for some advice. Have been to busy able to do anything on it since the last post.

Alongside the MDS solenoid code after making the post the truck put up a whole bunch of u codes at once. They came up right as I unplugged my code scanner, the screen did a little glitch then the CEL flashed. I scanned it and it came up with several codes which start with U.
U0121
U0100
U11BC
U1110

U0140 - this one, for the BCM, truck has had it for years, since being repaired after an accident, never poses a check engine or anyt issue, and it's last on the list, thought I'd still include it though.

I'll put pictures of my scanner screen with the code descriptions.

The truck runs and drives perfectly fine. The CEL flashes when first starting it but doesn't again. All of this is just based off of one drive post cam swap.

I got the parts store to test the battery for me, they said it's in perfect shape, but I'm not so sure since it's been used for 4 summers and 4 brutal winters to start this thing, and sat in my warm barn during the entire summer and last winter without being charged. It was just one of those handheld testers. I'll put those results in a picture too.

Can anyone think of anything I may have missed post cam swap, or something I can check up on? Electrical stuff is not at all what I'm good with really. I did create a new ground for the ground wires that go from the back of the heads. I reused the old ribbon like wire for head to head, then used a new ground cable from one of the heads to the grounding bolt between the battery area and fender. Could that be part of this?
Every one of these codes are lost communications between ECM BCM and antilock brake and brake switch
at least everything I have seen ! Is it poss that you pinched or broke a wire or wires?
 
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billetgrey

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Every one of these codes are lost communications between ECM BCM and antilock brake and brake switch
at least everything I have seen ! Is it poss that you pinched or broke a wire or wires?
I'd find it hard hard to believe if I did. It ran a good 10 minutes without any of these codes. Then while running it the first time, I used to code scanner to check codes that it's showing, just had the left over misfire code from before that cleared and a cyl 4 mds code. I tried clearing that a couple times. Then much later down the road I tried using the scanner again. Then when I disconnected the scanner, the whole electrical system of the truck had a little fart and all of these codes popped up.
 
Last edited:

Ken226

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It ran a good 10 minutes without any of these codes.
That's just about the right amount of time needed for a cable that's out of place, resting on something hot, to burn through, or one that is stretched, under tension due to poor routing, to be damaged from the movement of a running engine. Or, for a connector in an aforementioned condition, to be damaged.

Look at your trucks wiring diagram and inspect the canbus cables and connectors that link the modules showing stored codes.



Then when I disconnected the scanner, the whole electrical system of the truck had a little fart and all of these codes popped up.

This would make me wanna inspect the obd2 port and the wires, cables and connectors near the port. Also the pins in the port and anything else that could have been pulled, pushed or touched while down there.

Edt to add: double check the big BCM connector by the driver side kick well. It can get pulled loose easily and bring down part of the canbus network. I did it with my foot once while parked outside the grocery store.
 
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billetgrey

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That's just about the right amount of time needed for a cable that's out of place, resting on something hot, to burn through, or one that is stretched, under tension due to poor routing, to be damaged from the movement of a running engine. Or, for a connector in an aforementioned condition, to be damaged.

Look at your trucks wiring diagram and inspect the canbus cables and connectors that link the modules showing stored codes.





This would make me wanna inspect the obd2 port and the wires, cables and connectors near the port. Also the pins in the port and anything else that could have been pulled, pushed or touched while down there.

Edt to add: double check the big BCM connector by the driver side kick well. It can get pulled loose easily and bring down part of the canbus network. I did it with my foot once while parked outside the grocery store.
Thank you. Where could I get the wiring diagram for my 2014?
 

Ken226

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Thank you. Where could I get the wiring diagram for my 2014?
Try this:



After you download the service manual, use the search function to search for the code. You should find a page with a description of the code, the systems theory of operation, as well as wiring diagrams.

For example, U1110 is on page 9444.

1739758130306.png
 
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GTyankee

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read the pages below




The Powertrain Control Module (PCM) receives the brake switch signal over the Controller Area Network (CAN) C bus from the Anti-Lock Brake System (ABS) Module. The Diagnostic Trouble Code (DTC) sets when the PCM doesn't receive a brake switch signal from the ABS Module over the CAN C bus. One Trip fault

Check your BRAKE SWITCH at the brake pedal FIRST
you may have a wire off or loose
 
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billetgrey

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Try this:



After you download the service manual, use the search function to search for the code. You should find a page with a description of the code, the systems theory of operation, as well as wiring diagrams.

For example, U1110 is on page 9444.

View attachment 560871
The thing is, all of these functions still work, speedo works and no TC light, no abs light (didn't test the abs though) brake lights etc. Shouldn't these codes cause those functions to not work?
 

Ken226

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The thing is, all of these functions still work, speedo works and no TC light, no abs light (didn't test the abs though) brake lights etc. Shouldn't these codes cause those functions to not work?

The service manual doesn't say anything about those functions working or not. For U1110 it says:

1739826932157.png

You also have U0121 an U0140

All of these say the same thing. Lost communication with *** module.

The modules communicate over the CAN bus network.

This is a canbus issue. Start looking for damaged canbus wires.

1739827142582.png





For all of these "lost communication" and "lost speed message" codes at the same time, you are probably looking for a broken or loose connector.

Did you check the brake pedal and switch, as GTYankee suggested? That's a good place to start.

Also, check the wires around the BCM, if you havn't already.
 
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Hagar1

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Hi guys. Still tying up loosening ends on my truck post lifter+cam swap. Looking for some advice. Have been to busy able to do anything on it since the last post.

Alongside the MDS solenoid code after making the post the truck put up a whole bunch of u codes at once. They came up right as I unplugged my code scanner, the screen did a little glitch then the CEL flashed. I scanned it and it came up with several codes which start with U.
U0121
U0100
U11BC
U1110

U0140 - this one, for the BCM, truck has had it for years, since being repaired after an accident, never poses a check engine or anyt issue, and it's last on the list, thought I'd still include it though.

I'll put pictures of my scanner screen with the code descriptions.

The truck runs and drives perfectly fine. The CEL flashes when first starting it but doesn't again. All of this is just based off of one drive post cam swap.

I got the parts store to test the battery for me, they said it's in perfect shape, but I'm not so sure since it's been used for 4 summers and 4 brutal winters to start this thing, and sat in my warm barn during the entire summer and last winter without being charged. It was just one of those handheld testers. I'll put those results in a picture too.

Can anyone think of anything I may have missed post cam swap, or something I can check up on? Electrical stuff is not at all what I'm good with really. I did create a new ground for the ground wires that go from the back of the heads. I reused the old ribbon like wire for head to head, then used a new ground cable from one of the heads to the grounding bolt between the battery area and fender. Could that be part of this?
Did you change any sensors? I had a real shyte storm of U codes because of some cheap o2 sensors from Amazon. Changed them out, problem went away.
 
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billetgrey

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Did you change any sensors? I had a real shyte storm of U codes because of some cheap o2 sensors from Amazon. Changed them out, problem went away.
Just the water temp sensor since the old one with plastic threads wouldn't come out.
 
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