What do the blue lights mean? Will I see V4 Mode?

By: Ken Mosher11/18/2019 < Back to Blog Home
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Being a DISABLER, by definition, you will NOT see V4 Mode.

On the latest AFM DISABLER Modules, the four blue lights are basically to indicate the unit is operating. THEY WILL GO OUT WHEN THE VEHICLE IS NOT RUNNING as described below (Power Saving). The lights are as follows:


  • LED #1 - Power is ON and unit is AWAKE and vehicle is ready for commands
  • LED #2 - RPM > 500 and Engine is Running (not cranking or stalled)
  • LED #3 - Vehicle V8 mode is legal (no engine damaging DTCs present or other parameters out of spec)
  • LED #4 - In active command mode and controlling the AFM

The LEDs are numbered FROM RIGHT TO LEFT as you see them when plugged into the OBD2 port.

When you first plug the module into the OBD2 port, you may see the LED cycle in a pattern (units produced after Sept. 22rd 2014) which is just an indication that it is performing internal hardware diagnostic checks before going into full operating mode. Earlier modules may not cycle the LEDs (but still perform the hardware checks in "silent" mode).


During operation, it is normal to see the lights cycle and go on/off in different sequences sometimes appearing to dim or vary in brightness (or even almost go dark). The lights are not really useful to you as the driver, but are used more for diagnostic or status indications when doing troubleshooting/verification. You will see the lights dim dramatically as you slow down/brake. As long as the vehicle is staying in V8 the unit is operating normally.


Also, the units have a "SLEEP" mode where after you shut the key off and/or the engine is not running. All the LIGHTS WILL GO OUT and it will go into power saving mode. 

This power saving mode is EXTREMELY low powered and on a normal capacity battery in normal temperatures (i.e. ~70 degrees F) it should not affect normal battery voltage/charge for at least a couple of weeks (and probably much longer). The maximum draw in sleep mode is 6mA (and is nominally about 2-3mA).


The device will wake up again when you start the engine and the LEDs may cycle 2-3 times as the unit performs internal diagnostics. Earlier versions may not cycle the LEDs.


It may take up to 20 seconds (usually less) for it to start showing lights again ... this is NORMAL because it may take that long before we can send commands to the vehicle (especially on a cold motor).

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