GM AFM/DFM Disabler
Keep your V8 on all 8 cylinders
Plug it into the OBD-II port and Active Fuel Management stays off. No tuner, no reflash, no engine teardown.
- Plug-and-play, about 1 minute
- No tuner, no reflash
- Unplug = back to stock
- Built & shipped by Bo, Texas
Will it fit my truck?
Pick your truck and I’ll tell you if it fits.
I run these on my own trucks. — Bo
Heads up: not for 2019+ Silverado and Sierra with the 5.3L or 6.2L and the 10-speed.
Not for 2019+ Silverado and Sierra with the 5.3L or 6.2L and the 10-speed. Not on the list? Ask Bo before you order.
Bo’s shipping & returns
Bo’s shipping & returns
Free shipping. I make, pack and ship every order myself from Texas.
30-day returns. Changed your mind? You have 30 days after delivery to ask for a return.
Your GM engine is wearing itself out
Do nothing, and AFM keeps shutting half your cylinders off and back on, every mile you drive. That’s where the shudder, the tick and the big repair bills start.
The lifters take the hit
Special AFM lifters do all that switching, and they’re the best-known weak spot on these engines.
Shudder, ticking, misfires
You feel the shudder when it drops to V4. When a lifter starts to go, you hear a tick or get a misfire.
A lifter job often runs $3,000+
Fixing it means opening up the engine. That’s a big bill and a lot of days without your truck.
How it works
V8 → V4 → V8, over and over Plugging in… about a minute All 8 cylinders, no switching
-
1
Without the module
Cruise light and AFM shuts off cylinders 1, 4, 6 and 7, then wakes them back up. Every switch works the lifters.
-
2
Plug in Bo’s module
It goes into the OBD-II port under the dash. About a minute, no tools, no reflash.
-
3
With Bo’s module
AFM stays off: all eight cylinders, every mile, no switching. Unplug it any time and you’re back to stock.
Illustration of how AFM works, not a measurement.
Your two options
Plug-in or AFM delete
| Plug-in or AFM delete | Bo’s plug-in | AFM delete |
|---|---|---|
| Cost | $69.99 | $1,500–3,000+ |
| Engine teardown | None | Yes |
| Time | 1 minute | Days in a shop |
| Stops AFM switching | ||
| Back to stock | ||
| No tune or reflash |
Installed before your coffee cools
1. Find the port
The OBD-II port sits under the dash, near your left knee.
2. Plug it in
Push the module in until it seats. No tools.
3. Start the truck
Watch for the status light to come on.
4. Drive
All eight cylinders, every mile.
Will it fit my truck?
Pick your truck. If it’s on the list, you’re good to order.
Pick your truck and I’ll tell you if it fits.
I run these on my own trucks. — Bo
Heads up: not for 2019+ Silverado and Sierra with the 5.3L or 6.2L and the 10-speed.
Not for 2019+ Silverado and Sierra with the 5.3L or 6.2L and the 10-speed. Not on the list? Ask Bo before you order.
No tricks, just treats
Who’s behind this
Hi, I’m Bo
I’m Bodie McCoy — Bo to just about everybody. I’m 56, I live in Texas, and I’ve always been a pickup and RV guy.
Here’s how it works: I find a piece of gear that solves a real problem, build my own better version in my garage, run it on my own rigs, then pack it and ship it myself.
Bo’s plug-in
$69.99 now or a lifter job later
It plugs in in about a minute and comes out just as fast. I’d rather you spend $69.99 today than thousands on lifters down the road. — Bo
FAQ
Questions about the disabler
Still not sure? Send Bo a message and he will tell you straight.
Will it affect my warranty?
I can’t speak for your dealer. The module plugs in and comes out without tools and doesn’t reprogram the engine computer. If you’re under warranty, ask your dealer first, and unplug it before a service visit.
Will it fit my truck?
Use the fit check above; it follows the maker’s list. It is not for 2019+ Silverado and Sierra with the 5.3L or 6.2L and the 10-speed. Not on the list? Message me your year, model and engine before you order.
How hard is it to install?
About a minute. Find the OBD-II port under the dash, plug the module in and start the truck. No tools.
Will I use more fuel?
On the highway, a little. The engine stays on all eight instead of dropping to V4 at cruise, so expect fuel use to go up a bit there.
Will it turn on the check engine light?
It isn’t meant to. If a warning light does come on after you plug it in, unplug it and message me your year, model and engine.
Will it drain my battery?
It draws its power from the OBD-II port like any plug-in device. If the truck is going to sit for weeks, unplug it.
Is it OK to run on all eight all the time?
These engines run on all eight every time you pull, pass or tow. AFM only shuts cylinders off to save a little fuel at light cruise. With the module, it simply stays on eight.
What if it’s not for me?
You have 30 days after delivery to ask for a return. Shipping is free, and I make, pack and ship every order myself from Texas.
My engine already ticks. Will this fix it?
No, and I won’t tell you it will. If you already hear a tick or get a misfire, have the engine checked first. This keeps AFM switched off; it doesn’t repair a lifter that’s already worn.
Does it work on V6 engines?
Some, yes. A few GM V6s with AFM are on the list, like the 4.3L in 2014–2018 Silverado and Sierra. Check yours in the fit check.
What’s the difference between AFM and DFM?
AFM is GM’s older system that drops a V8 to four cylinders. DFM on newer engines can shut off cylinders in more patterns. Whether your truck is covered comes down to the list, so check the fit check or ask me.
Can I still use a scan tool?
Yes. Unplug the module, then plug your scan tool into the same port.