2021 Laramie 2500 Cummins won't start after Diesel Pre-Heat

[PaulHubbard]

This morning it got down to 48 degrees. Jumped in the truck, hit the start button, and the "Waiting for Diesel Pre-Heat" came on for 10 seconds - All normal and expected. Then the starter just clicked, the dash said "Fuel Filter Service Required". The filters were changed less than 2,000 miles ago. Now it goes into Pre-Heat, then just clicks, and a loud POP can be heard (I think from the stereo?), but no fuel filter message, and it goes right back to Diesel Pre-Heat (over and over). Any ideas? Thanks in advance!

 

[mtnrider]

Dead batteries, classic sign. Get them load tested but I guarantee you that's what it is. They only last 2-3 years in these trucks.

Even though everything turns on these trucks are very sensitive to have adequate voltage under load of starting. It's your batteries....
.

 

[TMyers]

Dead batteries, classic sign. Get them load tested but I guarantee you that's what it is. They only last 2-3 years in these trucks.

.

This is what I was typing as I got a message that someone else had posted. The grid heater and the cooler temps drained the failing batteries.

 

[PaulHubbard]

Tried each battery indendently by disconnecting one at a time. Chances of both batteries dying at the same time? Or does it *require* both batteries to be hooked up and fully functional? Voltage indicator reads 12.1v.

 

[Tulecreeper]

Tried each battery indendently by disconnecting one at a time. Chances of both batteries dying at the same time? Or does it *require* both batteries to be hooked up and fully functional? Voltage indicator reads 12.1v.

12.1 volts is less than 40% charged.

 

[crash68]

All it really takes is one bad cell between the two batteries to cause the this. If you really needed to get the truck started, you could try popping the ground off one or the other batteries, but better to jump start the truck.
Even if it's just one of the batteries that's weak, both of them need to be replaced at the same time lor the mismatch of the cells can cause rapid self discharging.

 

[mtnrider]

Tried each battery indendently by disconnecting one at a time. Chances of both batteries dying at the same time? Or does it *require* both batteries to be hooked up and fully functional? Voltage indicator reads 12.1v.

It will not start on 1 battery well (with the grid heater kicking on). Get them load tested, I guarantee one of them is low on cranking amps. It doesn't take much

 

[PaulHubbard]

All it really takes is one bad cell between the two batteries to cause the this. If you really needed to get the truck started, you could try popping the ground off one or the other batteries, but better to jump start the truck.
Even if it's just one of the batteries that's weak, both of them need to be replaced at the same time lor the mismatch of the cells can cause rapid self discharging.

I tried popping the ground off of each battery, one at a time, both act the same... It's still under warranty, will probably have the dealer diagnose, but it's just a pain to get it towed, be without, get a rental, etc...

 

[mtnrider]

Save yourself a tow and take them to a auto parts store and get them load test, you have a bad battery. This is all too common....

 

[TMyers]

I tried popping the ground off of each battery, one at a time, both act the same... It's still under warranty, will probably have the dealer diagnose, but it's just a pain to get it towed, be without, get a rental, etc...

Jump it off and drive it.

 

[PaulHubbard]

Save yourself a tow and take them to a auto parts store and get them load test, you have a bad battery. This is all too common....

Should it start with a jump? I have a power pack, that is said to have enough power to start my RAM, but it doesn't help at all...

 

[mtnrider]

Should it start with a jump? I have a power pack, that is said to have enough power to start my RAM, but it doesn't help at all...

Nope. If you have a bad cell it will just drag it down. Either way it won't last long. Pull them and get someone to take you to the auto store

 

[PaulHubbard]

Nope. If you have a bad cell it will just drag it down. Either way it won't last long. Pull them and get someone to take you to the auto store

Easier said than done... I think they hang the batteries (especially the passenger side) in the air then build the truck around them. ;-)

 

[mtnrider]

Easier said than done... I think they hang the batteries (especially the passenger side) in the air then build the truck around them. ;-)

Oh yeah, been there a couple of times already. They are heavy as heck trying to get them out of there.

.

 

[PaulHubbard]

Update: AAA came out, tested, found one battery was at 60%, replaced them both (for $508, not bad including labor) and we're good to go!!

 

[06 Dodge]

Update: AAA came out, tested, found one battery was at 60%, replaced them both (for $508, not bad including labor) and we're good to go!!

FYI, if ever needed ya can by pass the grid heater by pushing the start button twice...

 

[mtnrider]

Update: AAA came out, tested, found one battery was at 60%, replaced them both (for $508, not bad including labor) and we're good to go!!

Glad you got it sorted out. That's all it takes, just one a little low and it's all over. Always check them first when you have weird no start symptoms like that. Like I said 2-3 years is all you will get out of them (on average)

 

[JayLeonard]

12.1 volts is less than 40% charged.

50% according to the chart I have been using for years.

 

[Tulecreeper]

50% according to the chart I have been using for years.

Close enough - still far from fully charged.