Circuit Description

Serial data circuit is used to communicate information between systems. Each system on the serial data line is assigned its own identification number, which is used to identify which system is communicating. Systems periodically send a State of Health (SOH) message to other systems. If those systems fail to send an SOH message back, a corresponding DTC will be set. Also, any system that cannot communicate properly will set the corresponding DTC.

DTCs B1327 or B1328 must not be set current. When module detects no messages and high voltage on the Class 2 serial data link for approximately three seconds, U1301 will set. Setting of all other class 2 serial communication DTCs will be disabled.

If conditions for malfunction no longer exist, DTC U1301 requires an ignition cycle to change from current to history. DTC U1301 can be cleared using scan tool.