cylinder deactivation issue - dealer response

[tahoesteve]

Took my 2012 Tahoe LT to the dealer because the transition from 8 to 4 cylinders caused the truck to vibrate, especially at low speeds. A tech rode with me and agreed that it seemed excessive. Returning to the shop and reporting to the service writer what we found, he reached in drawer and pulled out a SB that sez it's normal. The tech said he found an update for the computer that would change the transmission shift points but it probably wouldn't adress the vibration. I like the way it shifts with the new settings and it seems the cylinder transition is a little less bothersome. I realize I'm not the first peson on the forum to bring this up. However, if your vehicle qualifies for the computer flash, you might want to consider it. Essentially, it shortens the time between shifts.

 

[goat364]

Thanks for the post! I have an 07 so i have a 4spd trans where you have the 6spd. But after installing a mild flowmaster exhaust the switch from v4 to v8 has gotten really noticable. It has always felt like the engine "lugs" in v4 and does vibrate the truck. Thanks to you i'm gonna look into what the dealer can do for me. I will probably have to pay for a tune but thats ok. My other option is to get a performance tuner myself and adjust the shift points and/or turn the cylinder deactivation off completely.

 

[bluepit36]

I have an 08 Tahoe and learned the AFM also burns about a quart of oil between oil changes if you don't check it regularly. I planned on buying a tuner but was given a Range Technology AFM disabler. You plug it in the OBD port and leave it in and it keeps your vehicle in V8 100% of the time. Supposedly it tells the vehicle to stay in V8 until you unplug it then it reverts back to AFM. It does work and no more semi-truck jake brake type sound from my exhaust. No more lag from switching from 4 to 8 cylinders either. I priced it and costs around $200. Pretty spendy for just an AFM disabler and not a tuner though.