B134613 - B134613 Refrigerant Temperature Sensor 1 Open Circuit

B134613 Detailed Fault Definition

B134613 is a specific vehicle diagnostic trouble code (DTC), specifically identified for the Refrigerant Temperature Sensor 1 open circuit state. In the vehicle thermal management and air conditioning control system, the sensor plays a key role, its core function is to provide real-time feedback data about the physical state of refrigerant in the air conditioning system to the control unit. When the system judges "Open Circuit", it means a physical interruption or electrical characteristic abnormality has occurred in the control signal transmission path, causing the Left Domain Controller to be unable to acquire an effective analog voltage signal. This fault definition is usually associated with the vehicle's closed-loop temperature control monitoring logic, its function is to ensure that actuators such as air conditioning compressor and expansion valve can work according to accurate refrigerant thermal state, preventing system damage due to overheating or overpressure.

Common Fault Symptoms

When B134613 code is recorded and warning light turns on, the vehicle's actual operating experience will be affected in the following dimensions:

• AC Cooling Performance Limited: AC system partially function failure, specifically manifested as compressor may not start/stop according to logic, or air outlet wind volume and temperature adjustment response sluggish.
• Dashboard Indicator Alarm: AC (Air Conditioning) fault light or engine management system related icons light up on the instrument panel, prompting driver to check refrigeration system status.
• Driving Environment Comfort Decreased: When external environment temperature is high, cabin interior cooling effect significantly weakened, or even completely lose cooling function, leading to vehicle interior temperature unable to maintain below set value.

Core Fault Cause Analysis

For the generation of B134613 fault code, from system architecture and signal pathway perspective, it can be summarized into the following three core dimensions potential triggers:

• Hardware Component Failure: The sensing element (such as thermistor or thermocouple) of the Refrigerant Temperature Sensor 1 itself may have suffered physical damage, open circuit or internal open, causing it unable to generate normal voltage divider signal.
• Wiring and Connector Abnormalities: Harness or connector failures are common signal transmission obstacle sources, including wire wear breakage, plug pin drop-out, loose connection or high resistance state caused by corrosion at connector interface, causing current path to disconnect.
• Controller Logic Unit Issues: Left Domain Controller Failure means the electronic control unit (ECU) internal circuit inside the vehicle has abnormal, may not be able to correctly read voltage signal or processor itself has hardware defect, leading to erroneous judgment of sensor open circuit.

Technical Monitoring and Trigger Logic

The generation of this fault code follows strict electrical parameter determination logic and operating condition conditions, specific monitoring mechanism as follows:

• Monitoring Target: Left Domain Controller continuously monitors real-time analog voltage output signal of Refrigerant Temperature Sensor 1.
• Voltage Threshold Determination: When the system detects sensor output voltage is higher than $4.95V$, controller will recognize the signal exceeds normal resistance divider range, thereby confirming signal line has open circuit characteristics (Open Circuit). This voltage value usually close or equal to reference voltage rail, indicating load end no effective loop formed.
• Trigger Condition: Fault judgment is only valid during ignition switch placed in ON position, at this time power supply established and control logic activated; if vehicle turned off, monitoring will pause until next ignition cycle.