Terrible Feature - Truck Shuts Off On It's Own?!?!

GTPprix · December 15, 2020

8 hours ago, bamorris2 said:

WAMS - In addition to programming it so that the truck doesn’t automatically turn off while idling in park, can you also make it so that accessory mode stays on indefinitely (or lengthen the timer)? I’m talking about the mode when you press the start button without your foot on the brake pedal).

Probably! Have not had a request for that thus far though.

kodiakdenali · December 15, 2020

3 hours ago, GTPprix said:

Probably! Have not had a request for that thus far though.

Especially if there would be a way to tie intermittent power into it as well, meaning it will stay on indefinitely -> unless the battery condition monitor indicates the battery is getting weak and there's a danger the truck might not be able to start the engine, in that case I'm good with accessory shutting down on its own.

GTPprix · December 15, 2020

May be able to lengthen the timer but when you start getting into logic it starts getting expensive real fast.

kodiakdenali · December 15, 2020

2 minutes ago, GTPprix said:

May be able to lengthen the timer but when you start getting into logic it starts getting expensive real fast.

understandable.

something really high on my wish list, that I'm not sure if its even a BCM function, but any chance you could come up with a way to make the truck start in sport mode every time? ideal world would be to have it remember what setting its in and go back to that setting automatically on the next start up. next best would be some way to control or pre-define what mode it starts in by default (driver can pick, set and forget, always start in the defined mode). I don't even run out of fingers on one hand before I count the number of times I've driven my truck in anything other than sport mode. or if all else fails, a way to make it start in sport always would be good enough. If no one comes up with a solution, I will build one myself. unfortunately it looks like GM has done something annoying with that control, based on the pinout its not a simple matter of creating a circuit that will short a couple of pins on the connector right after engine start. looks like its got a high reference and a low reference and a mode pin, which means you probably need to create and apply a properly calibrated voltage divider between the high and low to the mode wire...why did they have to do it this way? lol.

JDodge3 · December 18, 2020

OK, I purchased a 2020 Chevy Silverado 3500 for a fire department. The requisite emergency lights are installed and working. While working at a car wreck at night, using the truck to block traffic, with all the emergency lights on, the truck shuts off, including all the lights. Seems a bit dangerous, if I'm busy cutitng someone out of a car, to ahve all the lights shut off. Just seems a bit funny. The dealer said that there is no fix for this and GM said it would have to be done at the manufacturing plant.

Gilby Construction · December 19, 2020

21 hours ago, JDodge3 said:

OK, I purchased a 2020 Chevy Silverado 3500 for a fire department. The requisite emergency lights are installed and working. While working at a car wreck at night, using the truck to block traffic, with all the emergency lights on, the truck shuts off, including all the lights. Seems a bit dangerous, if I'm busy cutitng someone out of a car, to ahve all the lights shut off. Just seems a bit funny. The dealer said that there is no fix for this and GM said it would have to be done at the manufacturing plant.

It does seem a bit odd that there’s no way to change it

my 2020 3500 AT5 shuts off also

these are made to be work trucks and should be able to be changed easily - even if at the dealer

I’m going to try the neutral and park brake idea

Cjanik · December 20, 2020

On 12/18/2020 at 11:15 AM, JDodge3 said:

OK, I purchased a 2020 Chevy Silverado 3500 for a fire department. The requisite emergency lights are installed and working. While working at a car wreck at night, using the truck to block traffic, with all the emergency lights on, the truck shuts off, including all the lights. Seems a bit dangerous, if I'm busy cutitng someone out of a car, to ahve all the lights shut off. Just seems a bit funny. The dealer said that there is no fix for this and GM said it would have to be done at the manufacturing plant.

sounds like the installers need to find a better ignition sense source. I am a electronics/radio tech for my local agency. That loss of lights issue can be overcome, just make the installers aware of what its doing.

Edited December 20, 2020 by Cjanik

kodiakdenali · December 20, 2020

In a recent post in the thread about 6.2L spring defects someone posted a dealership procedure for testing doing a burn in run on the engine for 4.5h before sale was allowed. the procedure instructs the shop to start the engine by pushing and holding the start button for 15 seconds, indicating that this will bypass the auto shutoff for that ignition cycle. seems to be an undocumented feature. it does say that the trucks may not give any indication that the shutoff is bypassed whereas the SUVs should get a DIC message.

15 seconds feels like an eternity when you're holding a button down...its a pain, but way less of a pain than having your emergency lights shut off at the site of a roadside emergency or having the heater shut down if you're sleeping in the truck. would anyone have a good opportunity to test this out and see if it works?

kodiakdenali · December 20, 2020

On 12/15/2020 at 9:29 AM, GTPprix said:

May be able to lengthen the timer but when you start getting into logic it starts getting expensive real fast.

I sent you some questions a few days ago about the BCM reprogramming product, does the contact us thing on your site work? I haven't gotten a reply yet.

GTPprix · December 20, 2020

I sent you some questions a few days ago about the BCM reprogramming product, does the contact us thing on your site work? I haven't gotten a reply yet.

Yup it may have gone to your spam or if you have gmail it may have never gotten delivered due to the outages this week.

RWTJR · December 20, 2020

8 hours ago, kodiakdenali said:

In a recent post in the thread about 6.2L spring defects someone posted a dealership procedure for testing doing a burn in run on the engine for 4.5h before sale was allowed. the procedure instructs the shop to start the engine by pushing and holding the start button for 15 seconds, indicating that this will bypass the auto shutoff for that ignition cycle. seems to be an undocumented feature. it does say that the trucks may not give any indication that the shutoff is bypassed whereas the SUVs should get a DIC message.

15 seconds feels like an eternity when you're holding a button down...its a pain, but way less of a pain than having your emergency lights shut off at the site of a roadside emergency or having the heater shut down if you're sleeping in the truck. would anyone have a good opportunity to test this out and see if it works?

Good catch! This seems like a reasonable answer to the problem (assuming it works).

Why this isn't a documented feature is a mystery. I feel vehicle owners should have more and better control over all the automatic functions that seem to be increasing on new vehicles at an exponential rate.

JMHO

No expertise implied or expressed

bamorris2 · December 20, 2020

In a recent post in the thread about 6.2L spring defects someone posted a dealership procedure for testing doing a burn in run on the engine for 4.5h before sale was allowed. the procedure instructs the shop to start the engine by pushing and holding the start button for 15 seconds, indicating that this will bypass the auto shutoff for that ignition cycle. seems to be an undocumented feature. it does say that the trucks may not give any indication that the shutoff is bypassed whereas the SUVs should get a DIC message.
15 seconds feels like an eternity when you're holding a button down...its a pain, but way less of a pain than having your emergency lights shut off at the site of a roadside emergency or having the heater shut down if you're sleeping in the truck. would anyone have a good opportunity to test this out and see if it works?

Very interesting!! So foot ON the brake pedal and then hold button for 15 seconds? Or foot OFF the brake?