Multiplex Communication System

DIAGNOSTIC TROUBLE CODE CHART

B1211/11 - B1272/72:

If a malfunction code is displayed during the DTC check, check the circuit listed for that code in the table (Proceed to the troubleshooting given for that circuit).

HINT:
DTC 21-24 don't mean switch abnormal but notify how switch works.
If DTC is not output when operating switch, it means failure of switch contact.
If DTC is output when not opening switch, it means stick of switch.