truck not starting

[boatmanea]

2017 Ram 3500 dually 6.7l diesel 35,000 miles

Out of the blue, my truck decides not to start. Pressed the ignition and got a 'diesel warmup' message (it was 60 degrees outside!) Then tried to start, making one engine "turnover" noise, then nothing. Tried to start a few more times - same thing. Then the screens flicker and I get "service 4wd system" message. Ended up using my wife's car for the morning.

Later that afternoon, I check both batteries and both are holding at 13V. I run diagnostics and all I get is a "P24C7 particulate matter sensor temperature circuit range/performance" code. Not sure what to make of that. I try to start the truck, and it starts right up, no problem, no error messages, no flicker. I'm able to stop/start the engine about 10 times in a row without issue. Drove it a few miles - no messages or problems. Park it, and stop/start another 5 times - no problems. WTF?!?

Any ideas? Moisture in the sensor? Loose wires? Gremlins?

Thanks in advance.

-Erik

 

[17CrewCab1500]

Volts isn't what you really want to pay attention to with these trucks. You want to test amperage. IF the truck doesn't see the right amperage it will stop the truck from starting.

Check the battery connection on the passenger-side battery. Both ground and positive. Sometimes that can cause an issue.

 

[crash68]

If the turn over noises sounded like the engine was turning over slowly, I would have both batteries load tested. It's possible one of the cells is going bad.
If one is bad, unfortunately your looking at two new batteries, being a '17 it could still be under warranty.

 

[BossHogg]

It's possible one of the cells is going bad.

That is what it sounds like to me, I've had a single cell act up in the past. In my case, every once in a while the cell would flip its polarity bringing the battery potential to its knees then flip its polarity again. The way I caught it was monitoring the battery for several hours with a meter that could record minimum and maximum voltages.

I'm not a big fan of replacing both batteries because one failed, particularly when the batteries are not that old. The issue I described above, it was a brand new battery.

 

[boatmanea]

Problem solved. Bad cell in one of the OEM batteries. They were cheap-o no-name. Can't say I agree with you BossHogg on not replacing both batteries if they're crappy batteries to begin with. Can't afford to have that other battery go bad while we're on a long RV trip, so, two new Duralast gold batteries in place now with peace of mind.

 

[JohnnyMac]

Glad you found it. Thanks for letting us all know so it helps the next guy.

 

[boatmanea]

The trick with dual batteries that I learned is that one will "cover" for the other, giving the impression of good batteries (13V) when measured while still connected, but when you measure each individually WHEN DISCONNECTED, you will find the culprit - 10.5V on the driver side battery. The truck would start sometimes, with a little hesitation, so I probably wasn't far from the "bad cell" battery draining and killing the other.