Short answer
The OBD-II port is powered even with the engine off, so every plug-in disabler draws some current. Only BOOST publishes figures: 0.10 mA for its DFM (Global B) model and 0.71 mA for its AFM & DFM model. Others claim a sleep mode without a number, or say nothing. If the vehicle will sit a week or more, unplug it or switch it off.
Stated standby draw, every tracked model
We list what each maker or listing says. We don't measure current ourselves.
| Disabler | Engine-off draw | Switch |
|---|---|---|
| BOOST DFM Disabler (Global B) | 0.1 mA (stated) | No |
| BOOST AFM & DFM Disabler | 0.71 mA (stated) | No |
| Genapendex AFM/DFM Disabler | Sleep mode claimed, no figure | No |
| IceHeat AFM/DFM Disabler | Sleep mode claimed, no figure | Yes |
| FOSAJIK AFM/DFM Disabler (Smart Auto-Sleep) | Sleep mode claimed, no figure | No |
| FOSAJIK AFM/DFM Disabler with OBD pass-through | Sleep mode claimed, no figure | No |
| UltraEra DFM Disabler (2022.5–2026) | Sleep mode claimed, no figure | Yes |
| WishWeaver AFM/DFM Disabler with switch | Sleep mode claimed, no figure | Yes |
| Torqy AFM/DFM Disabler | Sleep mode claimed, no figure | Yes |
| JOPLAY AFM DFM Disabler | Sleep mode claimed, no figure | No |
| LYMAYDA AFM/DFM Disabler | Sleep mode claimed, no figure | No |
| KUYTN mini AFM/DFM Disabler | Sleep mode claimed, no figure | No |
| ROPODE AFM/DFM Disabler | Not stated | No |
| Range Technology RA003B AFM/DFM Disabler | "Virtually no draw", no figure | No |
| Range Technology RA007 DFM Disabler | Not stated | No |
| "American Design" AFM/DFM DOD Disabler | Not stated | No |
| OBDCAR AFM/DFM Disabler | Not stated | No |
| Max Cylinder AFM/DFM Disabler | Not stated | No |
| Glvvexa AFM Disabler (Silverado 2010–2018) | Not stated | No |
| RISEAID AFM/DFM Disabler | Not stated | No |
| CARAMAX AFM/DFM Disabler | Not stated | No |
| mataunion AFM/DFM Disabler | Not stated | Yes |
| CheerCode AFM DFM Disabler (V6/V8) | Not stated | No |
| CheerCode AFM/DFM Disabler (2007–2022 V8) | Not stated | Yes |
| NOOYEESMO "RA003" AFM Disabler | Not stated | No |
| METRICSQUARE AFM/DFM Disabler | Not stated | No |
| BELZAR AFM Disabler (Silverado 2010–2018) | Not stated | No |
| Carropecas AFM/DFM Disabler | Not stated | No |
| UltraEra AFM/DFM Disabler | Not stated | No |
| Bullro AFM/DFM Disabler | Not stated | No |
| Fioqe AFM/DFM Disabler | Not stated | No |
| CYTROBE "RA003" AFM/DFM Disabler | Not stated | No |
| Saicak AFM/DFM Disabler with switch | Not stated | Yes |
| ELFREE AFM/DFM Disabler (fault indicator) | Not stated | No |
| LUKYUCHA AFM/DFM Disabler | Not stated | No |
What a number means in days
Simple arithmetic, not a measurement: a 0.71 mA draw uses about 17 mAh a day, around 0.5 Ah a month. A typical truck battery holds 60 to 80 Ah, so the disabler alone is small. The catch is that your truck already has its own parasitic draw (modules, alarm, telematics), batteries age, and cold weather cuts capacity. An unknown draw from a cheap clone could be much higher. That's why owners still report dead batteries after a week or more.
What owners report
- A 2025 Sierra with a BOOST DFM: battery flat after six days parked, followed by a string of warning messages after recharging.
- A BOOST AFM & DFM owner: battery flat after one night (the battery may have been weak).
- OBDCAR and Max Cylinder: several "it drained my battery" reviews despite the listings.
- Range owners: Range's own advice is to unplug if the vehicle sits more than about three days.
Not always the disabler
On 2021+ Global B vehicles, GM itself issued a bulletin about battery drain after over-the-air updates. If your battery dies, test without the disabler before blaming it.
How to avoid it
- Choose a model with a published low draw or an on/off switch.
- Unplug it, or switch it off, if the vehicle will sit a week or more.
- Use an OBD extension cable with a switch if the port is hard to reach.
- Keep the battery healthy; have it tested if it's more than four or five years old.
Picks for low drain
For 2007–2022.0 vehicles, the BOOST AFM & DFM (0.71 mA stated) or a model with a switch such as the mataunion. For 2022.5+ trucks and 2021–2024 SUVs, the BOOST DFM (0.10 mA stated).
Questions owners ask
Does the Range AFM disabler drain the battery?
Range says "virtually no battery draw" without a figure, and recommends unplugging if the vehicle sits for more than a few days. Some owners report no issue, others a weak battery after long parking.
How long can my truck sit with a disabler plugged in?
With a healthy battery and a low-draw unit, usually several days to a week or more. With an older battery, other accessories or an unknown draw, it can be less. When in doubt, unplug it or switch it off.
Is an OBD extension with a switch a good idea?
Many owners use one so they can cut power to the disabler without reaching under the dash. Make sure the cable doesn't hang near the pedals.
Sources
- BOOST AFM & DFM and BOOST DFM (Global B) Amazon listings: stated engine-off draw, read October 27, 2026
- Range Technology RA003B page: "virtually no battery draw"
- Jalopnik: can an AFM disabler damage your engine (battery drain when parked)
- GM bulletin MC-11006207 (2024): battery drain on Global B vehicles after over-the-air updates
- Owner reviews of BOOST, Range, OBDCAR and Max Cylinder disablers on Amazon (our summary)