U1300

DTC U1300

CIRCUIT DESCRIPTION
Each control module connected to the class 2 serial data circuit monitors the voltage on the circuit. If a control module detects the class 2 serial data circuit is open or shorted for 3 seconds, all other class 2 serial communication DTCs are inhibited and DTC U1300, U1301, or U1305 will set.

DTC DESCRIPTORS
This diagnostic procedure supports the following DTCs.
- DTC U1300 Class 2 Data Link Low
- DTC U1301 Class 2 Data Link High
- DTC U1305 Class 2 Data Link Low or High

CONDITIONS FOR RUNNING THE DTCS
- Voltage supplied to the module is in the normal operating voltage range.
- The vehicle power mode requires serial data communication to occur.

CONDITIONS FOR SETTING THE DTCs
- No valid messages are detected on the class 2 serial data circuit.
- The voltage level detected on the class 2 serial data circuit is always low or always high.
- The above conditions are met for 3 seconds.

ACTION TAKEN WHEN THE DTCS SETS
- The module inhibits the setting of all other class 2 DTCs.
- The module uses default values for all parameters received on the class 2 serial data circuit.

CONDITIONS FOR CLEARING THE DTC
- A current DTC clears when the malfunction is no longer present, or when the ignition is cycled.
- A history DTC clears when the ignition has been cycled 100 times, without a repeat of the malfunction.

DIAGNOSTIC AIDS
- DTCs U1300, U1301, and U1305 cannot be retrieved while the condition is present. Diagnosis of these DTCs is accomplished via the symptom Scan Tool Does Not Communicate with a Class 2 Device. Refer to Scan Tool Does Not Communicate with Class 2 Device. Symptom Related Diagnostic Procedures
- An intermittent condition is likely to be caused by a short or an open on the class 2 serial data circuit. Use the Scan Tool Does Not Communicate with a Class 2 Device procedure in order to isolate an intermittent condition. Refer to Scan Tool Does Not Communicate with Class 2 Device. Symptom Related Diagnostic Procedures