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PLEASE take the time to read this page, lots of info here, I get a lot of email with questions about AFM delete that ARE answered on this page.  Thanks. My address and payment info for AFM Delete Service is at bottom of the page, along with my phone number.  I have gotten a lot of questions if I was still doing programming, answer is YES, I have not stopped doing programming, nor do I plan to at all. This is my full time job.  Thanks, Brendan - 5/30/2017

If you have found this page you may be experiencing issues with your 2007+ GM Truck or SUV that has the active fuel management, or sometimes called DOD (Displacement on Demand)  This is the system that shuts down half the lifters in the engine and places it in a 4 cylinder operation mode.  While this idea to shut down cylinders to reduce fuel consumption sounded great on paper, it has also been causing a lot of issues for people.  Some of the issues observed deal with oil consumption, fouled spark plugs, and in some cases failed lifters, and repeat failures of lifters.  Repair process gets expensive due to requirement of removing the cylinder heads to replace lifters.  I have been working with a few local shops; we have had 4 or 5 trucks in my small town already with repeated lifter failures after replacement with new AFM lifters.  The AFM lifters appear to fail two different ways.   I have seen the lifter come a apart, causing valves to bend, and have also seen them get stuck in a compressed position, causing valves to stay closed, and pushrod to bounce around unloaded.  I believe that the lifter should not fail as soon, or maybe not at all, if you disable the cycling from on to off of the AFM lifter.  There are some vehicles where I have seen worn lifter guides, causing the AFM lifter to rotate slightly, and go into deactivated position on its own, also there are issues with the oil control solenoids that leak oil when not commanded, also causing cylinder deactivation. 

sample of lifters, some old design, some newer, some locked down

new & old lifter design, both locked down. new design has larger oil feed for inner lifter body, and slot/pin to keep internal part from rotating

was locked down, old design, inner part allowed to rotate, wear on ledge pins sit on.

this lifter from same engine as picture left, same old design, but no wear at all.

new style lifter with pin to prevent rotation. now wear is concentrated in one area, this lifter was also locked down.

metal debris on pin, likey wedged in lifter causing to stay locked down


OIL CONSUMPTION:  It is my conclusion that the oil consumption has something to do with a spray or mist of oil created when the lifters exit the cylinder shut down mode and the oil used to compress the lifter is exhausted. This oil sprays on bottom of cylinders and enters the PCV system, drawn into the intake and burned. This means depending on each persons driving style, the more the engine enters/exits 4 cylinder mode, the more oil consumption you may see.  This theory is backed up by the presence of oil fouling on spark plugs, usually worse on the AFM cylinders, but is present on all 8 cylinders. I have also found some vehicles that replacing the valve cover with updated design on the drivers side is helping too. Some vehicles with 3+ qt consumption in an oil change the AFM delete dropped it by half, and valve cover replacement further dropped the oil consumption.  

I have programmed 100+ local trucks to simple disable the AFM. Last year I have programmed over 100 mail order ECM's for people doing hardware deletes using methods I describe here! Most notice almost no difference in fuel economy due to the very tight conditions required to enter 4 cylinder mode.  Oil consumption appears to be eliminated by disabling the AFM system, as would be expected if my above theory is correct.  Some vehicles may be too far gone; oil rings already to dirty to come back to life. I have seen a few vehicles that oil use tapered off over a year following AFM delete. 

DISABLING THE AFM SYSTEM: If your vehicle is currently running with no mechanical problems; meaning, no misfires due to no compression, no stuck lifters, no loud lifters, I believe simply programming the ECM to disable the AFM activation will prolong the life of the engine, and eliminate oil consumption.  If you have experienced a lifter failure, and have a cylinder with zero compression, lifter replacement is now required! I would highly suggest removing the AFM hardware from the engine since you will have the cylinders heads off anyways.  !!!PROGRAMMING REQUIRED IF YOU REMOVE THE AFM HARDWARE!!! If you remove the AFM components, and start the engine, DTC P3401, P3425, P3441, P3449 will set. These are codes for the 4 solenoids that control AFM. When these codes set, the PCM will disable the injectors for those cylinders.  So the ECM has to be programmed to disable those diagnostic codes.  See bottom of this page for programming info.

PARTS NEEDED (I do not list needed parts such as gaskets, head bolts, cam bolt, cam thrust plate if needed)

Valley Cover Plate - GM Part# 12598832 (about $45.00)  this will replace the stock valley cover that contains the oil control solenoids responsible for activating AFM. This new valley cover will also block off the 8 oil ports on the block. Should include gaskets.

Lifters - GM Part# 12499225 (16 new lifters, $167.00) Your AFM engine will have 8 standard lifters, and 8 AFM lifters.  This part# gets you 16 new standard lifters.

Lifter Guides - GM Part # 12595365 ($8.00 each) These are the plastic guides that keep the lifters from rotating, keeping the roller going correct direction on the cam lobe. These guides are different for AFM lifters, and you will need 4 of these.   

CAMSHAFT - The AFM engines have a special camshaft.  The mechanism required for the AFM lifters to turn on/off requires the individual lobes of the cam with AFM lifters riding on them to be DIFFERENT than adjacent lobes with standard lifters.  You MUST replace the camshaft if you are going to replace the AFM lifters with standard lifters.  Failure to do so will result in 4 cylinders that are about 25 lbs low on compression. This WILL cause misfires at idle.  (Learned this the hard way, take my word, CHANGE THE CAMSHAFT)

GM PART# 12625437 is the stock camshaft used in the 4.8L engine that DID NOT come with AFM.  This camshaft is a direct replacement for the 5.3L AFM cam when you want to do the AFM delete and use standard lifters.  This cam will have a groove in the 2nd bearing journal that is used to supply oil for use in VVT (variable valve timing) that started in 2010.  This cam works just fine in 07-09 WITHOUT VVT, as well as 10+ WITH VVT when deleting AFM from 5.3l engines.  This cam will use the stock timing gear and bolt from the 5.3L as well.  As of this writing, this cam is around $90.00 brand new from GM, you can also get it on Amazon, Summit Racing, so on.  Most all GM parts are on Amazon or Summit Racing.  I'm not sure how performance is affected using this cam on larger 6.0/6.2 engines. I would suggest using a factory LY6 camshaft used in 3/4T 6.0L truck applications 07-09. 

Another option for camshaft; the cheapest way is to find a used 4.8/5.3/6.0 camshaft from 1999 to 2007 Gen 3 engine that did not have AFM. These can often be had for as cheap as $20 online.  There is one small difference. The Gen 3 camshafts use 3 bolts to hold the timing gear on, and the 2007+ use a single large bolt in the center.  On the 2007+ engine you must use a cam gear that has a 4x trigger wheel for the camshaft position sensor.  GM Part# 12586481 has a 3 bolt flange, and 4x trigger and will do this task and costs about $25.00.  The gen 3 camshaft option WILL NOT WORK if you have a 2010+ with VVT.  In that case, use the previously listed GM PART# 12625437 camshaft.

Another option, is to purchase an upgraded performance camshaft.  If you go this route, such as a COMP cam, you can ask for a Gen 3 cam grind, made on a single bolt core.  You need to let them know your intention to remove the AFM lifters, and you need all the intake lobes the same, and all exhaust lobes the same.  Some cam manufactures are making camshafts to be used with the AFM lifters, so be sure to get this right...  On the 2007+ trucks even the smallest performance camshafts will need a custom tune to get it to run perfect. You need to find a local tuner or dyno shop to talk about options after the cam install.

VVT, Variable Valve Timing - Some vehicles starting in 2007 had VVT, the 6.0L LY6, L76, and 6.2L engine family in the trucks ALL had VVT. Starting in 2010 ALL 4.8/5.3 engines also had VVT.  This required a change to the camshaft, which will be a groove in the 2nd bearing journal to supply oil to the VVT control valve located inside the cam bolt on these engines.  If you are doing the AFM delete on an engine with VVT, you can decide to keep the VVT, or get rid of it too.  Removing VVT will require a new timing cover, cam gear, and cam gear bolt.  The camshaft part# 12625437 listed above will work with or without VVT.  IF YOU WILL BE DELETING VVT, AND I WILL BE PROGRAMMING YOUR ECM, YOU MUST LET ME KNOW BOTH AFM/VVT WILL BE DELETED, BY DEFAULT, I WILL ONLY DELETE AFM ON ECM'S I RECIEVE.

In an attempt to gain more data on this subject, I am offering special deal for AFM delete.  I hope to get feedback about oil consumption, fuel mileage, just any results. I will disable AFM and ship the ECM back to you for $50.00 including return shipping via US Postal Service Priority Mail.  AFM will be the only thing I will be modifying for this price. 


ECM should be original to the vehicle.  If you wish to purchase a spare ECM, and ship it instead, you will have to have security relearned.  The ECM you purchase MUST have the exact same Service Number on the white sticker. There is an additional $25 for VIN programming, select service below in the white box.  GM Sometimes has new software for your vehicle, including some recalls for emissions.  If you take your vehicle in for a recall that involves reprogramming the ECM, they will overwrite the AFM Delete programming I do.  This could result in only running on 4 cylinders if you have done a mechanical delete.  I can perform the same GM programming and get you the latest GM software for your vin.  To see what updates maybe available for your vehicle, click here, enter your VIN, click 'Get CAL ID', Select 'ECM Engine Control Module', click 'Next', and click 'Complete History'  This will show all software for your ECM specific to your VIN#.  There are 8 modules in your ECM.  Some scan tools will display what your current vehicle software is, and you can use this tool to see if updates are available, and what that update is for. If you want this service at time of AFM delete, select it below by clicking in the white box, and choose the option with VIN Program, and select which shipping option you want. Please note, an ecm which is programmed with NEW GM software, may require a relearn procedure once you get it back in and running. If you get  P0315 code, this will mean you need to have a "crankshaft position sensor variation lean" procedure done with a scan tool.  This code will not cause any poor running or issue, but will prevent ECM from detecting misfires until the relearn is completed.

IF YOU HAVE A 2005 or 2006 TRAILBLAZER, ENVOY, RAINIER, OR SAAB 9-7X with the LH6 5.3L, you have an E40 ECM, and programming for AFM delete is $150 total due to my programming hardware limitations on those applications.  I have to purchase a $100 license to program those ECM's.   Also, one other difference on these applications, I think you will have a 3 bolt camshaft already, so using the NEW camshaft part# I list above is not going to work for you.  You should find a used 99-07 LM7 camshaft. 2007+ Trailblazer, Envoy programming is same as 07+ pickup, use link below for $50.00

ECM LOCATION UNDER HOOD I only need the ECM, unplug it, and remove from bracket.

If you have these buttons, cycle top button until display shows 'instant economy''

You can monitor the vehicle cycling into/out of V4/V8 mode.

e38 ECM, used 07-14 trucks.

2007: 12597121

2008: 12612384

2009: 12625455

2010-11: 12633238

2012+ ????





Ship to:

Brendan Patten

7227 Private Road 1830

West Plains, MO 65775

If you mark the outside of the box with black marker in big letters AFM, and ship it to me USPS, I often will program, and ship back out the SAME DAY! Be sure payment is included inside the box, or made prior to me receiving the ECM for the quickest turn around time. Any questions on this call me, 417-257-0014

E-Mail with questions: brendan@lt1swap.com

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Why are you deleting AFM?