Circuit Description

Modules connected to class 2 serial data circuit monitor for serial data communications during normal vehicle operation. Operating information and commands are exchanged among modules. In addition to this, state of health messages are transmitted by each module on class 2 serial data circuit about once every 2 seconds. When module detects no messages on class 2 serial data circuit for approximately 3 seconds, U1305 is set and setting of all other class 2 serial communication DTCs is inhibited.

DTC U1305 sets when, no valid class 2 messages are detected on class 2 serial data circuit and condition is met for approximately 3 seconds.

When DTC sets, module inhibits setting of all other class 2 DTCs. Module uses default values for all parameters received on class 2 serial data circuit.

A current U1305 will clear when a valid class 2 message is detected on class 2 serial data circuit or at end of current ignition cycle. A history U1305 can be cleared with scan tool.