Automatic Start-Stop Feature (2019 Sierra Denali)

nealap · March 18, 2019

Is anyone else having an issue where the automatic start-stop feature on the vehicle stopped working? I just got the truck about 3 weeks ago (Brand New) and this is the only feature giving me an issue. It worked at first, but after driving it a week, it has not worked since. The only modification I have done on the truck is change out the License Plate light bulbs from halogen to LED. I'm at the dealership right now and they can't figure it out, so they are trying to contact GM regarding this issue. No error codes showing up according to them.

fish_guru · March 18, 2019

What exactly do you mean by not working? Are you talking about the switch to disable the feature or the truck is not turning off when it should (complete stop, with foot on the brake and the truck in gear)?

If it's the latter, sometimes if power consumption is too much (AC or heat on high) the truck will not turn off.

Edited March 19, 2019 by fish_guru
spelling

nealap · March 18, 2019

Not working as in the truck is not turning off when it should (at a complete stop with foot on the brake pedal). So I turned off the Climate control completely, and the truck still does not turn off. I even read the manual where it says if it is on a steep hill, it will not turn off. To test that, I was on a completely flat road and the truck still did not turn off at the red light.

eppieguy · March 18, 2019

I wish I had that issue!

Limelight · March 18, 2019

4 minutes ago, eppieguy said:

I wish I had that issue!

I agree!

Find out what's causing it and post it up so we can all share in the joy, lol.

nealap · March 18, 2019

To be honest, I hate the feature too. But I just want to be sure to fix it because I don’t know how it can affect the vehicle in the long run! Haha but for sure I will post what they find out once they tell me!

nealap · March 18, 2019

UPDATE: Dealer couldn’t figure it out. He said to bring it in again and they’re going to try to update the ECM. They’re not sure if the ECM will even fix the issue or not. Apparently their network was down so they were not able to carry out that update today. Apparently I’m the first out of everyone to experience this issue according to GM so yay me.

Rocz3cqg · March 18, 2019

Conditions for Auto Start/Stop

In a vehicle with a manual transmission, the transmission must be in Neutral and the clutch pedal fully released.
       Ambient and engine coolant temperature correlation must meet specified values.
       Ambient and transmission fluid temperature correlation must meet specified values.
       Hood switch status is closed.
       Brake pedal is depressed beyond a specific value (approximately 27%).
       Accelerator pedal is in the learned home position.
       Brake booster vacuum is greater than 45 kPa (7 PSI).
       Transmission gear selector is in the Drive position.
       Vehicle speed is less than 3 MPH (5 km/h).
       Engine speed is below 1500 RPM.
       Engine coolant temperature is less than 248°F (120°C).
       No A/C compressor request from the HVAC system (A/C or Defrost modes).
       Battery voltage greater than 12 V.
       Battery state of charge in the ECM is greater than 75% (changes with state of health).

Dougie86 · March 18, 2019

If it's colder than -5 celsius it will not shut off

gearheadesw · March 18, 2019

I'd leave it off also, forever.

jagabom (Esquire) · March 19, 2019

4 hours ago, Rocz3cqg said:

Conditions for Auto Start/Stop

The conditions are amazing for the stop/start to work.

Jim

Jessica Lambert · April 2, 2019

If it ever comes back on, the Autostop Eliminator will fix it for you. There a 15% off coupon code that works through April 15, 2019. Coupon code: FBGM

Limelight · April 2, 2019

1 hour ago, Jessica Lambert said:

If it ever comes back on, the Autostop Eliminator will fix it for you. There a 15% off coupon code that works through April 15, 2019. Coupon code: FBGM

Thanks for this! Just ordered one for a great price. Glad I waited.