Auto start stop troubleshooting.

[MadMatt3883]

Greetings. I just recently (last couple of weeks) picked up a used 2019 Silverado LT 2wd.  I’ve noticed that the auto start stop has never activated. I’m not getting any error messages and I don’t have a check engine light. I’m guessing the battery may be the issue. If the battery is from the factory, it’s probably just getting old. If the previous owner replaced the battery, maybe he didn’t replace it with an AGM battery.  I posted a couple of pics of the battery, just wondering if anybody can tell if this is the original battery or if it looks like a replacement. I’m not seeing any brand labeling on the battery, just the warning label on top. 

Edited March 6, 2023 by MadMatt3883
Added text.

[AntonyU21]

It is recommended to ask a professional mechanic

[silveradosid]

battery has nothing to do with the auto stop, start. previous owner might have an auto start stop delete installed in the truck

[MadMatt3883]

7 hours ago, AntonyU21 said:

It is recommended to ask a professional mechanic

I’m not spending money to fix this. If it’s an easy fix I’ll do it, otherwise I’ll leave it alone. 

[MadMatt3883]

1 hour ago, silveradosid said:

battery has nothing to do with the auto stop, start. previous owner might have an auto start stop delete installed in the truck

Are you talking about the aftermarket cable installed behind the switch?

[jaxcam02]

Have you ever checked to see if the truck has an aftermarket tune. I'm betting thats your answer

[PhilB]

Actually, the battery has a lot to do with the auto stop/start.  If the computer detects that the battery voltage is low, it will not allow the auto stop/start to function.  This has happened on my Silverado and Traverse.  Both times I had to have the battery replaced.  Problem solved.  One way to test, which I did on the Traverse, was to connect a battery charger to the battery and let it charge overnight.  Then for the next several days the auto stop/start worked.  After that, it quit working.  After a few weeks of driving it around and it wasn't functioning, I took it to the dealer who confirmed it was the battery.  

 

I know a lot of folks on here hate the auto stop/start, but I look at it as the canary in the coal mine.  When it stops functioning, there is an issue with the electrical system.  Could be the battery, could be the alternator, could be the current/temp sensors, etc.  Just my opinion.... 

 

It could also be like the others have posted above, the previous owner did something to disable it.  

Edited March 7, 2023 by PhilB

[MadMatt3883]

7 hours ago, jaxcam02 said:

Have you ever checked to see if the truck has an aftermarket tune. I'm betting thats your answer

No. What type of ODB scanner would I need for that?

[MadMatt3883]

8 hours ago, PhilB said:

Actually, the battery has a lot to do with the auto stop/start.  If the computer detects that the battery voltage is low, it will not allow the auto stop/start to function.  This has happened on my Silverado and Traverse.  Both times I had to have the battery replaced.  Problem solved.  One way to test, which I did on the Traverse, was to connect a battery charger to the battery and let it charge overnight.  Then for the next several days the auto stop/start worked.  After that, it quit working.  After a few weeks of driving it around and it wasn't functioning, I took it to the dealer who confirmed it was the battery.  

 

I know a lot of folks on here hate the auto stop/start, but I look at it as the canary in the coal mine.  When it stops functioning, there is an issue with the electrical system.  Could be the battery, could be the alternator, could be the current/temp sensors, etc.  Just my opinion.... 

 

It could also be like the others have posted above, the previous owner did something to disable it.  

My money is on the battery. I was hoping someone would be able to recognize my battery as being factory or not factory. When I have time I’m going to take it to autozone and have the battery tested. 
 

Edit:  pulled the top cover off. Factory battery. Now I have a check engine light after disconnecting the battery lol. 

Edited March 7, 2023 by MadMatt3883
Added pic.

[jaxcam02]

4 hours ago, MadMatt3883 said:

No. What type of ODB scanner would I need for that?

If you've exhausted the battery and it's not the cause,  you'll need to find a tuner to look if the truck has been tuned. The dealer can also look at the tune counter and tell you. Simple obd scanner won't tell you anything. 

[MadMatt3883]

20 minutes ago, jaxcam02 said:

If you've exhausted the battery and it's not the cause,  you'll need to find a tuner to look if the truck has been tuned. The dealer can also look at the tune counter and tell you. Simple obd scanner won't tell you anything. 

When I get a chance I’m going to test the battery.  That battery is 4 years old now.  I’m in south Texas and down here car/truck batteries suffer from early deaths due to the heat.  

[MadMatt3883]

So I can rule out a tune. Out of nowhere it started working today. 

[PhilB]

Could have been a loose connection that corrected itself when you removed and reinstalled the battery cover.  Just a thought.  IIRC, there was something about the bolts that hold the connector board in the battery cover that needed tightening.  

 

Keep us updated.  

[newdude]

Here is the entire possibilities list of why the auto stop would disable.  I bolded a few candidates that are either somewhat obvious reasons it wouldn't work, and some not so obvious inhibiting reasons.  The auto start disable list is about identical. 

 

I don't see where these trucks use it per the description and operation, but some of the earlier stop/start that GM used had some sort of an internal timer counter or something that the dealer can go in and reset.  Chances are if these use the same thing, you pulling the battery reset the counter.  

 

Autostop Disable Reason - Transmission Range

 

Autostop Disable Reason - Passenger Compartment Heater On

 

Autostop Disable Reason - Driver Exited Vehicle

 

Autostop Disable Reason - 12V Start Counter Exceeded

 

Autostop Disable Reason - Vehicle Inclination

 

Autostop Disable Reason - Remote Vehicle Start Request

 

Autostop Disable Reason - Acceleration Request

 

Autostop Disable Reason - Transmission In Reverse

 

Autostop Disable Reason - Reduced Engine Power Active

 

Autostop Disable Reason - Transmission Range

 

Autostop Disable Reason - Ignition Switch Start

 

Autostop Disable Reason - TCM Request

 

Autostop Disable Reason - System Optimization

 

Autostop Disable Reason - System Voltage Low

 

Autostop Disable Reason - Engine Coolant Temperature Out Of Range

 

Autostop Disable Reason - Catalyst Test In Progress

 

Autostop Disable Reason - HO2S Test In Progress

 

Autostop Disable Reason - Misfire Test In Progress

 

Autostop Disable Reason - Catalyst not at Operating Temperature

 

Autostop Disable Reason - Intake Manifold Temperature Too High

 

Autostop Disable Reason - Engine Speed Test in Progress

 

Autostop Disable Reason - MAF sensor Test In Progress

 

Autostop Disable Reason - MAP Sensor Test In Progress

 

Autostop Disable Reason - Engine Oil Temperature Too High

 

Autostop Disable Reason - Engine Stop/Start Test in Progress

 

Autostop Disable Reason - Engine Coolant Temperature Test In Progress

 

Autostop Disable Reason - EVAP System Test In Progress

 

Autostop Disable Reason - Fuel Injector Test In Progress

 

Autostop Disable Reason - Fuel Pressure Test In Progress

 

Autostop Disable Reason - Fuel System Test In Progress

 

Autostop Disable Reason - Parking Maneuver Detected

 

Autostop Disable Reason - High Engine Rotating Torque

 

Autostop Disable Reason - BARO Pressure Too Low

 

Autostop Disable Reason - Fuel Temperature Too High

 

Autostop Disable Reason - System Malfunction

 

Autostop Disable Reason - Turbocharger Temperature Too High

 

Autostop Disable Reason - Hood Ajar

 

Autostop Disable Reason - ECM Request

 

Autostop Disable Reason - Run/Crank Not Active

 

Autostop Disable Reason - Minimum Engine Run Time Not Met

 

Autostop Disable Reason - Control Function Active

 

Autostop Disable Reason - Auxiliary Transmission Fluid Pump/Accumulator Not Available

 

Autostop Disable Reason - Engine Coolant Temperature Out of Range

 

Autostop Disable Reason - Invalid Data Received

 

Autostop Disable Reason - Vehicle Speed Too High

 

Autostop Disable Reason - Transmission Fluid Temperature Out of Range

 

Autostop Disable Reason - Brake Pedal Released

 

Autostop Disable Reason - Brake Booster Weak Vacuum

 

Autostop Disable Reason - Accelerator Pedal Pressed

 

Autostop Disable Reason - A/C Request

 

Autostop Disable Reason - Low-Voltage Battery Voltage Low

 

Autostop Disable Reason - Low-Voltage Battery State of Health Low

 

Autostop Disable Reason - Low-Voltage Battery State of Charge Low

 

Autostop Disable Reason - Low-Voltage Battery Discharge Current High

 

Autostop Disable Reason - Intake Manifold Weak Vacuum

 

Autostop Disable Reason - Engine Speed High

 

Autostop Disable Reason - Wheel Slip Detected

 

Autostop Disable Reason - Vehicle Speed Threshold Not Reached

 

Autostop Disable Reason - Maximum Vehicle Stop Time Exceeded

 

Autostop Disable Reason - Starter System Malfunction

 

Autostop Disable Reason - System Malfunction

 

Autostop Disable Reason - Stop/Start Select Switch

 

Autostop Disable Reason - Idle Boost Mode Active

 

Autostop Disable Reason - Generator Load High

 

Autostop Disable Reason - Low-Voltage Battery Temperature Out of Range

 

Autostop Disable Reason - Low-Voltage Battery State of Function Low

Edited March 14, 2023 by newdude

[MadMatt3883]

I found the issue. There’s no problem. The transmission fluid temperature isn’t hot enough. Unlike my previous truck (F150) the transmission in this truck heats up real slow. My daily commute to work is about 17 miles one way and is mostly highway.  The hottest the fluid gets on one leg of the commute is about 115-135.  I noticed when the fluid gets to about 165 is when auto start/stop begins to engage. In my case, that hardly ever happens.