I was reviewing the service manual and it mentioned a TSB wherein, when servicing the hybrid, you have to turn off and remove the key. leaving it in ON might trigger auto/stop mode. anybody experience it? I tried putting it in ON and tried to change gear and press the gas, it did not start/move the vehicle I wanted it to turn ON when the key is in ON position so you don't have to twist the key to start but have anybody tried it? thanks! it would have been a cool feature like the prius.

 

No, I did read about someone killing the 12v battery by leaving the truck in 'on' to listen to the radio. They had to jump the 12v battery to start the car. I thought this was strange because I thought the truck started from the 300v and the tranny basically bump starting the engine. I could be wrong on this starting process, but the dead battery issue was posted on the tahoe forum last year sometime.

So that tells me, that no, it won't start the truck.

 

If the Tahoe starts like the Accord IMA system you are correct. But the 12V battery voltage is needed in the Honda system and it must be at a minimium voltage in order for the IMA system to start the vehicle. If the 12V battery voltage is to low the car will not start.

The first time I ever drove a Accord Hybrid the dealer had let the 12v battery run down below the required voltage. The dash lights and gauges were all nice and bright but the car would not make even the slightest sound like it was trying to start. One of the mechanics went and got one of those little portable battery jump boxes and within about 1 second of his hooking it to the 12V battery the car started the instant the key was turned. Clearly all the car wanted was a voltage number higher than that being supplied by the weak 12V battery. It was certainly not providing the starting power.

Just a guess but the GM probably works in a similiar fashion. (FWIW the Honda does have a conventional starter also and will use it in certain situations and that would require a strong 12V battery.)

 

Yes, very similar, and the reason is the 12V system runs a bunch of systems, including the ECU, that are needed to start the car. If the battery is below a threshold (10.2V?) then it will lock-out starting. It isn't like the old days when the car would crank slowly...

The warning about key-off, is in-case they had it running and it auto-stopped, then they wouldn't get their hand stuck in a belt or other spinning thingy. That is why the auto-stop is disabled with the hood open, to let you know the key is still on.

 

One of the electric motors in the transmission also acts like a starter. Just an item of note if you leave the truck running after starting it will eventually go into auto-stop and it will also do this sometimes during the remote start 10 min interval. There are other options/features i would like to see before the push start, although it is nice.

 

Jeremy: you must always crank the 2 Mode trucks. Just turning to run will power up most the systems but you won't get any torque applied to the wheels until the engine has actually run. The whole system must be active.

A fully warmed up 2 Mode will crank and run the engine for short time, about 10 seconds. Then it should settle into Auto-Stop.

Once in Auto-Stop, if you pop the hood latch the engine cranks up. You don't want a hand near the belt when the engine comes on so the engine lets you know it is operational.

The 2 Mode is capable of a Prius like start but GM chose not to enable that as a feature.

Not sure why.

 

Just curious, what is a 'Prius like start?'

 

T-Pole In the Prius I just think you push a start button.