U1300

DTC U1300 Class 2 Short To Ground:

DTC U1301 Class 2 Short To Battery:

CIRCUIT DESCRIPTION
Modules connected to the Class 2 data link monitor the link for serial data communications during normal vehicle operation. Operating information and commands are exchanged among the modules. In addition to this, Node Alive (State of Health) messages are transmitted by each module on the data link about once every 2 seconds. When the Body Control Module (BCM) and radio receiver detects no messages and a low voltage on the data link for approximately 3 seconds, U1300 is set and the setting of all other communication DTCs is inhibited.

CONDITIONS FOR SETTING THE DTC
^ Voltage supplied to the modules are in the normal operating voltage range (approximately 9-16 volts).
^ No valid Class 2 messages are detected on the data link.
^ The voltage level detected on the data link is low.
^ The above conditions are all met simultaneously for 3 seconds.

CONDITIONS FOR CLEARING THE DTC
^ A current U1300 will clear when a valid Class 2 message is detected on the data link or at the end of the current ignition cycle.
^ A history U1300 will clear upon receipt of a scan tool CLEAR DTCs command.

DIAGNOSTIC AIDS
^ This DTC cannot be retrieved with a current status. Diagnosis of a current U1300 is accomplished via the symptom, Scan Tool Will Not Communicate With the Class 2 Serial Data Line.
^ An intermittent condition is likely to be caused by a short to ground on the Class 2 serial data line.
^ To assist in diagnosis, refer to Wiring Systems and the DLC schematics.