Check Engine Light after jump start (1 Viewer)

[dms]

My 18 LC is kept in storage most of the time. I usually try to drive it around every couple of weeks and even then, my battery is often weak (replace battery about 6 months ago). Yesterday, I tried to start and after a couple of groans, it started clicking so I took my power cell and after connecting the negative to the terminal as soon as I connected the positive, the lights came on which lead me to believe that the ignition was somehow still on. I jumped in and hit the start button which immediately brought the beast to live and disconnected the power cell. As soon as I got back into the seat, I noticed that the check engine light was on and the trac control was off and the button was unresponsive.
I turned the truck off and after a few minutes repeated the process to see if it might re-set itself (no luck).
Being Saturday afternoon, I decided to take it to the dealership and let them sort it out.
Any thoughts as to what damage I have done?

 

[Lou Gill]

Try disconnecting the battery and why don’t you try keeping the battery on a battery tender?

 

[dms]

Try disconnecting the battery and why don’t you try keeping the battery on a battery tender?

I would use a tender, but there is no power. I am going to try to figure out a way to power a tender.

 

[Sandroad]

The dealer will read the CEL code for diagnosis. I suspect the repeated low/dead battery is not something the truck likes. It could be resetting the codes will clear things up. Simply jump starting would not normally damage anything. Although I think the recommended procedure is to connect the positive first and then connect the negative at a chassis ground and not at the battery to make sure a spark doesn’t cause problem. If you can’t get a trickle charger on it in storage, when you drive every couple weeks, take a bit of a trip. It’s important in your scenario to get the battery fully charged between uses. If you have been almost fully discharging the battery regularly and finally killed it this time, you may need another new battery. They sulfate up in that kind of abuse. There is always the possibility your truck has an electrical issue. Is it stored inside? Any possibility of rodent damage?

 

[dms]

The dealer will read the CEL code for diagnosis. I suspect the repeated low/dead battery is not something the truck likes. It could be resetting the codes will clear things up. Simply jump starting would not normally damage anything. Although I think the recommended procedure is to connect the positive first and then connect the negative at a chassis ground and not at the battery to make sure a spark doesn’t cause problem. If you can’t get a trickle charger on it in storage, when you drive every couple weeks, take a bit of a trip. It’s important in your scenario to get the battery fully charged between uses. If you have been almost fully discharging the battery regularly and finally killed it this time, you may need another new battery. They sulfate up in that kind of abuse. There is always the possibility your truck has an electrical issue. Is it stored inside? Any possibility of rodent damage?

I am certain that it is not driven enough. My power cell does not have the cable length to get a good ground on the chassis so I opt for the negative terminal. I know there is no rodent damage. I store it inside in town rather than in the barn at the farm where I would worry much more about rodents. That being said, I recently purchased some spray to put on the mowers and gator to help prevent rodent damage. I told the dealership to put in a new "Toyota" battery even though my Autozone battery was still within warranty.

 

[Boston Mangler]

I would use a tender, but there is no power. I am going to try to figure out a way to power a tender.

I got a solar panel tender off of amazon for my Ram diesel that sometime sits for months at a time

It does its job, and the suction cups make it easy to remove and install without issue:

https://www.amazon.com/Battery-Portable-Waterproof-Maintainer-conversion/dp/B07JLWFPX6/ref=sr_1_2_sspa?crid=125XK6O1MSPQK&dib=eyJ2IjoiMSJ9.CTcfaSa6eJP4G7yDOBBeFONEPDPlsGAi9ELLIWVZCAegD-0YaBR2z8ZQ8dnaNMdu2eJ84wwgF69NabWS2Y8x7k7VjxSfGWw3LbaadvLD3lzn690jDYDqxsmBM1-pCYtdKd75dFmYH3x3WXNKBWD_WF-geZHyXcAuAZ-Nl88NOKhcfm8HmKxtqgdqLLQsjDSc58OduMQjuBUmiTIt9MiyZyzYxGJ_DgwaA67K42OM_J4.veVS0xmVORkkvNMAeZcX0xAQ32BBrYPAElwutebva48&dib_tag=se&keywords=solar+battery+tender+12v+automotive&qid=1713103342&sprefix=solar+battery+t%2Caps%2C156&sr=8-2-spons&sp_csd=d2lkZ2V0TmFtZT1zcF9hdGY&psc=1

 

[FrazzledHunter]

These trucks can throw codes when the battery dies and you then restart them.
I had the battery run down camping and jump started the truck with the 2nd battery.
The truck started but in limp-in mode and it couldn't be driven.
In a hail-Mary move I used Blue Driver to clear a very strange error code I got after running the battery down.
Without Blue Driver it would have been a very expensive tow from a remote location.
Clearing the code with Blue Driver "fixed" the problem and it hasn't returned even though the battery has been disconnected for service more than once since them.

This whole thing is baffling to me.

Here's the post I made about the whole fiasco:
REF:

Error code P0121 brake override malfunction solved in the field - https://forum.ih8mud.com/threads/error-code-p0121-brake-override-malfunction-solved-in-the-field.1321119/#post-15129436

 

[doru]

I would put a new deep cycle battery not the regular starting battery. The deep ones are made for this kind of abuse.
The I'll put a solar powered trickle charger on it.
Finally I'll buy an OBDII dongle and phone app to read and reset codes when needed. Search the forum, there was a discussion on this a few days back.

Finally Christmas tree lights are to be expected when battery goes low on most modern vehicles.

 

[08URJ200]

Disconnecting the negative terminal will slow the battery draining in my experience. YMMV. Tinder is the way to go if feasible but in the interim removing the negative helps significantly.

 

[HighRanch]

I have had similar issue with running my battery down and recharging with my NOCO charger.
The car started and I received check engine light and decided to drive to mechanic and initially got strange transmission
lurching.....after taking the car to the mechanic they ran diagnostics and told me that they loaded a SW fix to the transmission.
Still not sure what this was all about, but agree these trucks don't do well when the battery goes dead.

 

[bloc]

I have had similar issue with running my battery down and recharging with my NOCO charger.
The car started and I received check engine light and decided to drive to mechanic and initially got strange transmission
lurching.....after taking the car to the mechanic they ran diagnostics and told me that they loaded a SW fix to the transmission.
Still not sure what this was all about, but agree these trucks don't do well when the battery goes dead.

16-21 model with the 8-spd? If so yes there was a TSB and software update for the transmission to address some undesirable behavior during normal driving.

In your case having everything reset may have also reset the clutch learn values so it was especially bad.. but yes many people report a big improvement in the 8spd after the update.

 

[dms]

Thanks for all of the input and advice!!! Replacing the battery solved the issues. Now to figure out how to covertly place a solar panel at my storage unit so I can utilize a battery tender.