Preventing DOD\AFM troubles

TJBaker57

Original poster
Lifetime VIP Donor
Member
Aug 16, 2015
3,213
Colorado
So I have noodled about briefly this AM seeking "best practices" for preventing AFM Lifter failure. Not an issue for myself but I learned yesterday that a friend has just acquired a 2007 Ranier with LH6. 152xxx miles. 3 previous owners, all within an hours drive here locally. Looks sharp & clean and is fairly "loaded" options wise.

Anyway it would seem that frequent oil changing with high quality oil is standard? I would imagine a full synthetic, right?

I ran a VIN check for maintenance history and there is none for the first 8 or so years of it's life but that in itself is not surprising given my remote location. The garages here are very unlikely to participate in such reporting.

Also just came across this pdf from Melling...


Then there will be the normal operations to do for a new acquisition like changing the transfer case AutoTrak fluid etc.

Who's got additional advisements??
 

northcreek

Member
Jan 15, 2012
3,374
WNY
Anyway it would seem that frequent oil changing with high quality oil is standard? I would imagine a full synthetic, right?
I had an 07 Envoy Denali with the LH6. I ran Mobil 1, changed via the OLM and never had a problem with the AFM . I traded it at 120 K miles and it was still going strong . I did check the screen at that mileage and it was clean as a whistle.
 

Mooseman

Moderator
Dec 4, 2011
26,034
Ottawa, ON
The best way to prevent an AFM failure is to disable it. Failure happens when cylinder deactivation was commanded and when it tries to reactivate it, one lifter fails to return to normal and stays in a collapsed state.

Short term, you can unplug the vacuum sensor located on the brake booster. You will get a CEL for the disconnected sensor. Long term, it can be permanently disabled via a tune or using something like the Range AFM disabler, both of which will prevent the CEL and code from setting however the Range, if unplugged for an e-test, will allow it to go into AFM. I recommend a tune.

It doesn't matter if it was well cared for with regular oil changes, it will eventually fail. It is a mechanical design flaw of the lifter. If it's stopped from activating, it should live the rest of its life as a normal lifter.
 
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Mramses

Member
Jul 19, 2020
322
17176352
La mejor manera de evitar una falla de AFM es deshabilitarlo. La falla ocurre cuando se ordenó la desactivación del cilindro y cuando intenta reactivarlo, un elevador no logra volver a la normalidad y queda colapsado.

A corto plazo, puede desconectar el sensor de vacío ubicado en el servofreno. Obtendrá un CEL para el sensor desconectado. A largo plazo, se puede deshabilitar permanentemente a través de una melodía o usando algo como el desactivador Range AFM, los cuales evitarán que el CEL y el código se configuren; sin embargo, Range, si se desconecta para una prueba electrónica, permitirá que entre en AFM . Recomiendo una melodía.

No importa si se cuidó bien con cambios regulares de aceite, eventualmente fallará. Es un defecto de diseño mecánico del levantador. Si deja de activarse, debería vivir el resto de su vida como un levantador normal.
Buenas noches amigo. Espero que te encuentres bien. ¿Podría guiarme más sobre cómo deshabilitar AFM para un vortec TrailBlazer 5.3l 2007, por favor? Lo poco que me he informado es sobre la GAMA pero soy de Venezuela y quisiera saber si actualmente hay otras alternativas para desactivar el AFM de la camioneta.
gracias
 

Mramses

Member
Jul 19, 2020
322
17176352
Buenas noches amigo. Espero que te encuentres bien. ¿Podría guiarme más sobre cómo deshabilitar AFM para un vortec TrailBlazer 5.3l 2007, por favor? Lo poco que me informó es sobre la GAMA pero soy de Venezuela y quisiera saber si actualmente hay otras alternativas para desactivar el AFM de la camioneta.
gracias
Es posible desactivar sin usar el RANGE?
 

Mooseman

Moderator
Dec 4, 2011
26,034
Ottawa, ON
English please as per the rules.
 

TollKeeper

Supporting Donor
Member
Dec 3, 2011
8,255
Brighton, CO
Goodnight friend. I hope you are well. Could you guide me further on how to disable AFM for a 2007 vortec TrailBlazer 5.3l please? The little that I have informed myself is about the GAMA but I am from Venezuela and I would like to know if there are currently other alternatives to deactivate the AFM of the truck.
thank you
There is only one way to disable the AFM/DOD.. Tune it, modify the VLOM, and put the oil block bung in.

CrazedPerformanceRepair on YouTube has many videos about it.
 
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