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Discussion Starter #1
It’s a 2015 ram fully deleted with mm3. Back in December I went to drive it after sitting for a few weeks and the battery’s were dead so I jumped it off my wrangler and started no problem and drove it for the weekend with no issues. I put a tender on it the next weekend for the winter. I went out last weekend to start it and there was nothing happening. Key still unlocks the doors and interior lights come on but when I put the key in the only thing that happens is the dash gets brighter. When I turn the key nothing happens. No more lights no dinging no radio like I’m not even key. Though maybe the batteries where toast so I put new ones in, no change. Checked all fuses I could think of and couldn’t find any bad ones. Tried the spare key and no change either. Unhooked batteries for the night to see if something, anything would reset, no change. I called the shop I use and he’s afraid I cooked the ECU when I jumped it. I’ve been searching the internet the past couple of day but couldn’t find much with this particular problem. And if it is the ECU, what would be he next step? Thanks in advance.
Matt
 

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Have you tried a new or your spare key maybe key fob went bad.

Sent from my ONEPLUS A6013 using Tapatalk
 

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Have you tried a new or your spare key maybe key fob went bad.

Sent from my ONEPLUS A6013 using Tapatalk
I agree, put a new battery in the FOB..sounds like the truck sat parked for 3 months
 

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It’s a 2015 ram fully deleted with mm3. Back in December I went to drive it after sitting for a few weeks and the battery’s were dead so I jumped it off my wrangler and started no problem and drove it for the weekend with no issues. I put a tender on it the next weekend for the winter. I went out last weekend to start it and there was nothing happening. Key still unlocks the doors and interior lights come on but when I put the key in the only thing that happens is the dash gets brighter. When I turn the key nothing happens. No more lights no dinging no radio like I’m not even key. Though maybe the batteries where toast so I put new ones in, no change. Checked all fuses I could think of and couldn’t find any bad ones. Tried the spare key and no change either. Unhooked batteries for the night to see if something, anything would reset, no change. I called the shop I use and he’s afraid I cooked the ECU when I jumped it. I’ve been searching the internet the past couple of day but couldn’t find much with this particular problem. And if it is the ECU, what would be he next step? Thanks in advance.
Matt
Buh, Buh, Buh....... Ive been told countless times that's not possible. :confused013:

It is. As in 'very'. And you don't even have to reverse the cables.

I'd look for a loose ground somewhere before I threw in the towel. I don't see how, in this case, you fried the computer. this time..... hopefully

Does the grid heater come on? I assume not. Look for that loose ground. You might need the help of a pro with the correct gauges/instruments to track it down. Might even be a dead short. Could also, very likely, be in your tuner.

I serioously doubt this has anything to do with anything, but I put an analyzer on mine when it was cold enough out for the grid heater to come on, and turned the ignition....... Nothing. A mess. The ECU had a nervous breakdown. Had to disconnect the batteries and let it reset. Took it to the Dealer for a warranty problem and it showed up for them. I did not confess.

Good luck.
 

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I agree, put a new battery in the FOB..sounds like the truck sat parked for 3 months
On another vehicle I had, I noticed that if the Key Fob is within a certain distance..... If it can communicate with the vehicle or is almost able to communicate with the vehicle, it will wear down the Key Fob battery more quickly.

So if your truck is in the garage and you hang the Key Fob in the kitchen, 15 feet away.....

But that's a WAG. Defintely replace the battery in the Fob before spending any money
 

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On another vehicle I had, I noticed that if the Key Fob is within a certain distance..... If it can communicate with the vehicle or is almost able to communicate with the vehicle, it will wear down the Key Fob battery more quickly.

So if your truck is in the garage and you hang the Key Fob in the kitchen, 15 feet away.....

But that's a WAG. Defintely replace the battery in the Fob before spending any money
That happened to my Harley, key FOB communicates with the bike if the key is too close. FOB battery went dead.
I wonder if the OP left the key in or near the truck while it sat parked for the winter.
 

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One thing that can definitely be ruled out is the key fob battery, because you don’t even need one in the fob for the truck to start. The battery in the fob is only for the remote lock/unlock/start functions.
Does the message “key fob not detected” display in the EVIC? When they say the ECU is cooked, which one are they referring to? ECU and ECM are generic terms for any electronic control unit/control module on the truck.
 

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One other possibility is there is a voltage sensor on these trucks and I that my have got damage when jumped. If that goes bad won't kick starter on.

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That happened to my Harley, key FOB communicates with the bike if the key is too close. FOB battery went dead.
I wonder if the OP left the key in or near the truck while it sat parked for the winter.
Exactly what I was talking about. Had to put my keys in another room to where they wouldn't try to interact with the bike.

I have no clue if the Ram is like that but I don't see what's different about the Key Fobs.

I always carry a spare coin battery with me. Always.

If I ever need it, finding it might be a challenge.
 

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Was the Wrangler running when you hooked up to the RAM and started the diesel?
The problem arises when BOTH vehicles are running at the same time. The Jumpee and the Jumper. The vehicle's system is getting blasted with both alternators wide-open. Hitting it as hard as they can. Which can result in a french fried computer.

I believe our (Mine does, anyway) has a delay on it until the Alternator kicks on. Probably for that exact reason.

If you stand around and scratch yourself and let both vehicles run, it can sometimes cause damage.

I'm hoping, for the sake of the OP, that it isn't the ECU. They're pretty tough these days. But not indestructible
 

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Discussion Starter #12
I change both FOB batteries, no change. The wrangler was running when I jumped the truck. I took the cables off right away. Do these trucks have some sort of security on them?
 

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I change both FOB batteries, no change. The wrangler was running when I jumped the truck. I took the cables off right away. Do these trucks have some sort of security on them?
the only security system i can think of is the chip in the keyfob
 

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I wonder if it's possible that the tender fried it??

I'd start looking for loose ground wires (and other loose wires as well) and maybe at the tuner. Might be a BCM. Was there a recall on yours?? dunno

If you have to have it towed, let us know what was wrong with it after it's fixed. please
 

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the only security system i can think of is the chip in the keyfob
....which needs to verify the secret key information with the PCM and the RF hub. If the SKIM system detects a VIN mismatch or other info that doesn’t line up, the truck will start and die immediately. If a fob went bad or lost it’s programming somehow, when the key is inserted, the PCM and RF hub won’t recognize it and should display a message like “fob not detected”. If nothing is happening at all when the key is inserted and turned, it could be a bad ignition switch, bad rf hub, or bad PCM (not verifying secret key information at all).
 

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I"ve not had any issues jumping anything off with the Ram (including the other ram). I've had the batteries replaced in both recently, and the 2017 often got jump duty for the Lexus before I sold it.... and the Jeep.

Apparently batteries and I don't get along...

So I would say the the chances of frying the ECU are small; but I suppose it's possible...

I've also seen it where (and this was true on my 2017) there was enough voltage to light up the basics, but the ECU would not allow anything else to occur without more juice. Replaced the truck batteries, and all was well with the world.

Please note that in this state, attempting to jump start it wouldn't even work.... It would do absolutely nothing.

Honestly I would get your truck batteries tested before I went any further. These trucks are super sensitive to voltage/amperage and will do some weird things when it's not correct
 

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You need to load test both batteries separately and disconnected. Replace both even one is a little bad. Make sure all terminals are perfectly cleaned to metal and tight.
 

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Discussion Starter #19
The weather is supposed to clear up today so I’ll get out and mess around with the truck again. If nothing turns up does anyone have a dealer in the Cleveland/Akron Ohio area they like and think would be helpful. I assume that’s about my only option.
 

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dude, replace both batteries first. It's $350. The stock batteries last less than 2 years on average.

Your signature doesn't say how old your truck is; but... I'm guessing it's at least two years old, since even a brand new 2018 is now over a year old...
 
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