Recently my dealership noticed the B2102 diagnostic trouble code (DTC) has been stored in my Evo X during a service visit. This happened previously, but they were unable to find out the cause.

Long story short, we brought in the master tech and he did a few tests. It turned out that this relates to the (aftermarket) remote starter. As a manual car, if I turn off the engine without stepping on the brake, the remote starter will keep the engine running and stop the engine only after I have closed the doors and locked the car. In that way, the remote starter knows that the shifter is left in neutral for remote starting.

Evo X's (factory) ECU will register an event whenever the ignition switch (knob) is turned off, but the actual ignition is still on (i.e. engine still running). If this event happens 10 times, it will store a B2102 code.

So the bottom line is that there is nothing to worry about if you have a similar remote starter that keeps the engine running after you turn off the ignition switch (knob).

 

In case if anyone cannot see the MEDIC screenshot above:

The shortcoming with the MEDIC hints is that it does not take into consideration that many Evo X's have remote starters. If an inexperienced technician relies on the MEDIC tool only, he or she will end up running circles diagnosing CAN bus line, the switch, and the ECU's without realizing the stored B2102 code is normal with the remote starter.