Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
DTC U1301: Class 2 Data Link Shorted To Power: 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 and a high voltage on class 2 serial data circuit for approximately 3 seconds, U1301 is set. Setting of all other class 2 serial communication DTCs is inhibited.
DTC U1301 is set when no valid messages are detected on class 2 serial data circuit. Voltage level detected on class 2 serial data circuit is high. Conditions are met for approximately 3 seconds.
When DTC U1301 is set module inhibits setting of all other class 2 DTCs. Module uses default values for all parameters received on class 2 serial data circuit.
Current DTC U1301 will clear and become a history DTC when a valid class 2 message is detected on class 2 serial data circuit or at end of current ignition cycle. History DTC U1301 will clear after 100 ignition on/off cycles with no repeated malfunction.
NO RELATED
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- β’ You smell fuel, burning insulation, or see smoke.
- β’ Brakes feel soft, pull hard to one side, or make grinding noises.
- β’ The engine overheats, stalls repeatedly, or misfires under load.
- β’ You are missing required tools, torque specs, or safe lifting equipment.
- β’ You are not confident in the next step or safety outcome.