Reflash for Funky O2 Codes
This bulletin applies to 2014 Dodge Challenger, Charger and Chrysler 300 vehicles equipped with a 5.7L engine and built on or before Sept.4, 2013. A MIL may be on, with DTC P1621 (O2 sensor reference voltage circuit low) or P1622 (O2 sensor reference voltage circuit high).
The fix involves selectively erasing and reprogramming the PCM with new software at release 14.01 or higher. Using a scan tool (wiTECH), verify that all engine systems are functioning as designed. If DTCs other than the two noted here are present, record and repair as needed before reflashing.
Install a battery charger to ensure that battery voltage does not drop below 13.2 volts or rise above 13.5 volts during the flash process.