6.7L MegaCab

On Sunday when we loaded up to go to church the truck wouldn't turn over and just clicked. Which I found highly strange since it worked perfectly fine the night before (nothing was powered on, all lights were off). We ended up taking the Aspen so after we got home I went to Sears to pick up a couple Diehard Advanced Gold AGM batteries (that's all they had). I couldn't jump the truck either because I was nosed into the driveway against the garage.

Before I replaced the batteries I was getting the U0141 DTC again along with the IC acting up and sometimes the truck would not start because communication could not be established with the ECM (cycling the key a few times with the door open would fix it). Also, the power inverter had a distinct sound when the truck would start, similar to the sound that a store bought inverter would make when it didn't have enough juice (except nothing was plugged into the truck's outlet). Before I removed the old batteries, I checked the DTCs and had both the U0141 and a low power code (don't recall the number). Another issue I noticed happening over the last couple weeks was a slight buzz was coming from the Black Maxx.

After I installed the new batteries the check engine light went away and now the power inverter is no longer making noise after starting the truck, something it had been doing for at least the last year maybe 2 years. The BM is no longer buzzing either. I was adamant about replacing the batteries, so I didn't have the old ones checked, although I wish I did to see how bad they really were.

Is it possible if a battery is going out that the TIPM wouldn't be getting enough juice to power everything else it controls thus causing all the weird electrical issues? I know older vehicles could run on alternator alone, but if the battery was bad, then only a few systems would be powered by the alternator. Is the same true for our trucks?

I find it quite funny that all this happened Sunday because I finally broke down and bought the AutoEnginuity last Thursday (received yesterday) to try to diagnose the U0141 and the Aspen's check engine light, only to have the truck's batteries give out over night.

For those that aren't familiar, see my past threads, especially the "scared the bejeebers out of me" thread from 2012 and work your way forward from there.

Anyhow, just curious what y'all thought about this.

Sent from my Nexus 5 using Tapatalk

WeldinGas

When I worked on Cadillac's at the dealer back 8 years ago or so you would not imagine the weird issues a simple loose ground would cause. GM used the side post batteries and they could not keep them from leaking for some reason. We would have battery replacements all the time because the female threaded portion would come out after leaking. Battery trays(under rear seat) completely eaten away exposing the road below.


Several times we had cars come in with complaints of lights buzzing, instrument cluster flickering on and off, buzzers and just really off the wall stuff. Raise the back seat, pull out your trusty 8mm wrench and give the little bolts a turn, 9 times out of 10 the cable would fall right off. Replace the battery and issue solved. This was just about a daily occurrence in a large city shop. When we had issues electrically one thing we always checked was grounds and battery connections. Poor grounds can cause host of problems.


Dropping below 10 volts on todays electronically controlled vehicles and what you are describing sounds like standard operating procedure. Just enough to kind of power things up but not sustain it. Low voltage and grounds can cause crazy things, I have seen them first hand. With todays vehicles you have grounds everywhere, several on the engine, in the cabin of the vehicle, chassis. Old days you might have had handful.

6.7L MegaCab

That's pretty crazy. I can't believe someone in their right mind would put a battery inside a vehicle.

The passenger side positive post was ever so slightly wet when I disconnected the cable... So more than likely that battery was done.

I was thinking about the grounds yesterday. With everything that was disconnected through all of the modifications, some of those have a ground connection for the components they were connected to, so I'm kinda wondering with those being disconnected if that could cause an issue? I would think not, but you never know as one component disconnected could have separated one or multiple ground paths for other components, even though everything is working fine so far. I've looked at the chassis grounds and they all look good.

Sent from my Nexus 5 using Tapatalk

WeldinGas

Mercedes, BMW, Cadillac have had batteries under the rear seats for years. Cadillac finally went to top post batteries around 2005 I think, not for sure but around there.


Yeah, individual components/modules, a.k.a, computers with their own ground needs to be connected. I can't say that they are causing issues but as I said, electrical problems were what I thrived on at the dealer, loved them and saw some crazy poop happen with grounds, just simple things you wouldn't think about.


Resistance thru your ground cable for your battery, corrosion internally on the wires of the cable or your positive lead. I can't remember the voltage on the cars when they started getting weird but seems like it was around 10.5, 10 for sure. Below that and it was a crap shoot.

6.7L MegaCab

When I can catch a break from my class, I'll get out there and check the resistance on the ground wires. Before I swapped batteries, I did check the voltage. It was sitting at 12.32 with both connected. I was in a rush to swap because of my class so I forgot to check them individually before handing them over to Sears. I'll take a closer look for any corrosion on the pos/neg cables but I don't think there is any. There wasn't a hint of corrosion on the batteries... not that it means much. No computer components have their ground disconnected, just sensors and modules removed from the deletes....I will pull the TIPM off eventually based on pics I've seen online of them where the bottoms have holes... at least on the Jeeps... to check for any corrosion on the connectors.

Thanks for the help so far, much appreciated.

Sent from my Nexus 5 using Tapatalk

6.7L MegaCab

Nothing wrong with the grounds, but the issue came up again yesterday as far as all the computer gremlins I've been having. It may be the TIPM, but it is so random I don't have the patience or time to take it to the dealer. But I haven't had a single problem with the nav radio like I was having before. The nav would sometimes hang on the last location I was at when I shut it down and it would take a couple restarts to fix itself. The GPS would work just fine, just the icon stay put or just move around in relation to the direction I was traveling.