U1301

U1301 - Class II Data Link High


Modules connected to the Class II serial data circuit monitor for serial data communication during normal vehicle operation. Operation commands are exchanged among the modules. In addition to this, Node Alive (State of Health) messages are transmitted by each module on the Class II serial circuit about once every 2 - 5 seconds. When the module detects no messages and a high voltage on the Class II serial data circuit for approximately three seconds, U1301 is set and the setting of all other communication DTCs is inhibited.

Diagnostic Aids
^ This DTC cannot be retrieved with a current status. Diagnosis of a history U1301 is accomplished via the symptom No Communication On Class II Data Link
^ An intermittent is diagnosed by using the No Communication On Class II Link to isolate an intermittent short to ground.
^ A current U1301 will clear when a valid Class II message is detected on the Class II serial data circuit or at the end of the current ignition cycle.
^ A history U1301 will clear after completion of 100 ignition switch ON/OFF cycles with no repeated malfunction.
^ When this DTC sets, all other DTCs are inhibited.
^ This code is checked for and will set if the voltage supplied to the modules is between 9 - 16 volts. If there are no valid Class II messages on the Class II line for 3 seconds or if the voltage level on the Class II data circuit is high for 3 seconds, this code will set.