MM3 Trouble Led To An Unexpected Discovery

**Acerock** · 09-23-2022

I have a 2019 Ram 2500 tuned via an MM3.

Recently it started giving me trouble upon engine startup.

The MM3 wouldn't boot up and required unplugging it from the OBD2 plug and plugging it back in.

I checked the troubleshooting guide that mentioned a possible problem with the memory card but what I found odd was that it would boot simply turned the ignition to run but didn't start the engine; once the starter was engaged, it would shut off and flash a sequence of red & green flashes.

That forced me to check my truck's batteries.

I had one shot battery giving out only 10 volts, and the other was strong at 12.7. I probably wouldn't have discovered this as quickly because the engine was still starting pretty well.

I'm sure as soon as the weather turned cold, it would have left me stranded!

So bottom line, listen to what this nifty little device is trying to tell you; it saved me a bunch of grief down the line.

Since my other battery was strong, the truck never gave me warnings.

I'm glad the MM3 warned me, even if it wasn't intended!

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