U0100 code

[Joe Merchak]

Hey guys,

So today I was driving the truck and had to stop at the bank for my wife. When she went in I shut it down but left it on acc so I could listen to the radio. When she came back out the truck would not start. I turned it off and back on, nothing. I open the doors and nothing. I finally open and closed doors, locked and unlock the truck and then the engine started. A mile down the road the check engine light came on and the truck had no power. The truck never went into eco mode so I took it back home. I read the code and it was U0100. Letting the truck off for 3 hours the code is still there. Any of you had this issue?

Truck is a 2018 express with the hemi and 8 speed.

Figures too, it was just in the shop yesterday getting its first service.

Thanks

Joe

 

[kad]

U0100 = Lost Communication with ECM/PCM

-K

 

[ExpressRules]

Disconnect the battery for 10 minutes or so, then restart to see if it goes away.

 

[Jrod]

Disconnecting the battery may clear the code, but cross your fingers for it to stay clear. If it’s an actual problem the code will repop within minutes or a couple of days. Just FYI

 

[Joe Merchak]

Thanks guys. I think I just take it to ram and have them figure it out. Don’t want to remove the battery since they won’t be able to figure what is wrong

 

[Joe Merchak]

SO talk to the dealer yesterday and got them to bring it in right away once I get there. I go home, start the truck and no light. I am like what the "f". I call the dealer back and said it was still up to me but without the light it going to be hard to diagnose. At this time I am pissed and just park the truck. About 3 hour later talking to my friend, he suggested I re-read the computer. I have a scanner that will read all the modules so I did a full system scan. It had all these store codes but it makes made no sense. Once was could not talk to transmission but when I was driving it around I could manually change gears and it function perfectly. Another said power steering was non functional, again it worked perfectly. There were a few other again no issues with the truck. So I decided to clear all codes and would drive it to work and see how it ran. So far no code and no issue.

This all happened after we had 4 days of 0 or below 0 temps. Yesterday it was 60, could all of this be battery related? I bought it in Aug and it only has 5K on the truck.

Joe

 

[kad]

SO talk to the dealer yesterday and got them to bring it in right away once I get there. I go home, start the truck and no light. I am like what the "f". I call the dealer back and said it was still up to me but without the light it going to be hard to diagnose. At this time I am pissed and just park the truck. About 3 hour later talking to my friend, he suggested I re-read the computer. I have a scanner that will read all the modules so I did a full system scan. It had all these store codes but it makes made no sense. Once was could not talk to transmission but when I was driving it around I could manually change gears and it function perfectly. Another said power steering was non functional, again it worked perfectly. There were a few other again no issues with the truck. So I decided to clear all codes and would drive it to work and see how it ran. So far no code and no issue.

This all happened after we had 4 days of 0 or below 0 temps. Yesterday it was 60, could all of this be battery related? I bought it in Aug and it only has 5K on the truck.

Joe

It could be, these trucks do very strange things when the battery is on it's way out. But it certainly should not be failing due to age this fast so if it is, it's a defective battery IMO.

You're in NJ? I'm a few hours north of you in NY and we had the same cold snap. Other than her not being real happy when first started (some minor belt squealing) I had no issues with the cold snap. My truck lives outdoors and I do not have a block heater or battery tender, but I DO have a brand new AGM battery just put in this last fall.

-K

 

[Joe Merchak]

I live in Hackettstown which is exit 19 off Interstate 80. The truck sat for the whole cold snap, Friday was the first time I drove it in a week. The truck is used for running around the weekend and pulling my travel trailer so it sits usually 5 days a week in the winter. I am going to see what happens but its really weird.

 

[kad]

I live in Hackettstown which is exit 19 off Interstate 80. The truck sat for the whole cold snap, Friday was the first time I drove it in a week. The truck is used for running around the weekend and pulling my travel trailer so it sits usually 5 days a week in the winter. I am going to see what happens but its really weird.

Good luck with it. Come back to this thread in a week or so and let us know how it goes. (That's how we keep the knowledge flowing around here! )

-K

 

[Joe Merchak]

So drove the truck today, light came on then off. Now I have pending codes

U0100
U1197
C006A
U0415
U0102

This really sucks. Goes in Thursday.

 

[Joe Merchak]

Well they spent the day yesterday working on it and have no clue how to fix it. They said they will let me know today and see if they have a answer. They did confirm the code I told them were there in the system.

 

[Joe Merchak]

So got the truck back friday. They had to replace the ABS module. It was crashing the bus and that is why all the codes were showing. I talk to the tech and he did it by his gut because he seen the issue before in other trucks. Drove the truck all weekends and still no code so I guess he is right. Crazy how one module can take down the truck.

 

[LoadedExpressRam]

So got the truck back friday. They had to replace the ABS module. It was crashing the bus and that is why all the codes were showing. I talk to the tech and he did it by his gut because he seen the issue before in other trucks. Drove the truck all weekends and still no code so I guess he is right. Crazy how one module can take down the truck.

Would you happen to have the actual part number on the module they replaced? It seems i may be having this issue. Appreciate any help.

 

[Joe Merchak]

Yea let me look for the repair order.

 

[LoadedExpressRam]

Yea let me look for the repair order.

Disregard buddy i appreciate it though. Turns out it was just the bracket that holds my brake pedal switch was bent causing the switch to not deactivate. The metal that holds the switch in place is some what flimsy. Thanks again.

 

[Joe Merchak]

oh ok because i did get it, it was part 68295368AC

 

[HemiPower36]

Has this problem come back since? I have have a no start/ no crank with U0100 code. I am trying to fix it on my own because the dealer will try and sell me everything under the sun. Google isn't helping, seems like the problems could be a list of countless things..... sucks.

 

[Joe Merchak]

Nope its been fine since they fixed it.