2015 Jeep Wrangler P0622 Fault: Alternator or ECM? Transmission Shift Issues

I own a 2015 Jeep Wrangler Sport Unlimited with a 3.6L V6 engine. Recently, my transmission has been malfunctioning — it refuses to shift into gear properly unless I manually force the shift. The vehicle has died five times during driving, and on two occasions, after restarting, it would not engage any gears (D or R). After turning it off and waiting, it eventually started shifting again. However, yesterday it failed to start at all. I checked the diagnostic codes and found P062-2. According to the code lookup, this indicates an alternator issue or a problem with the Powertrain Control Module (PCM) — though the alternator was tested and confirmed functional. AutoZone ran a diagnostic and suggested I check the Engine Control Module (ECM). I'm now uncertain whether the issue lies with the ECM or the PCM. Any insights or recommendations would be greatly appreciated.