Some owners of 2007-2013 Chevy Avalanche, 2007-2018 Silverado, 2019 Silverado LD and 2500/3500, and 2007-2020 Tahoe vehicles may comment of an intermittent SIR MIL. When checking for DTCs, any of the following may be set: B0012, B0013, B0014, B0015, B0019, B0020, B0021 and/or B0022. In most cases, it will have symptom codes for both high and low loop resistance.
This concern could be caused by interference from an aftermarket USB and/or phone charger plugged into the 12-volt power outlet.
If, after following normal diagnostics and the root cause is not found, inspect the vehicle and/or question the customer if they are using any type of USB/phone charger, etc. In the example screenshot shown here, the scan tool was used to monitor the suspect air bag loop resistance while using/operating the aftermarket item plugged into the 12-volt power outlet.
If the concern is intermittent and/or cannot be duplicated, ask the owner to refrain from using anything that is plugged into the 12-volt power outlets and see if the issue goes away.
