B133413 - B133413 Refrigerant Temperature Sensor 2 Open Circuit

meaning of this code points to an open circuit (Open Circuit) state in the circuit of "Refrigerant Temperature Sensor 2". As a key feedback component in the air conditioning refrigeration cycle, this sensor is mainly responsible for converting the real-time physical temperature of liquid or gaseous refrigerant into electrical signals and feeding them back to the Right Domain Controller. The Right Domain Controller, as an important node in the vehicle electronic architecture, uses the voltage signal to calculate thermodynamic load and execute compressor load strategies. When the system detects infinite impedance or no connection in the sensor loop, it is judged to be an open circuit fault. At this time, the control unit cannot obtain accurate physical position and rotation speed-like (analogous to motor control logic) temperature feedback, leading to interruption of closed-loop control strategy and triggering corresponding diagnostic identifiers.

Common Fault Symptoms

When the diagnostic monitoring system confirms the presence of code B133413, the vehicle's thermal management subsystem will enter a protection or degradation mode. Specific changes in driving experience perceived by car owners are as follows:

• Partial air conditioning system functionality loss: Due to inability to obtain precise temperature feedback data, the Right Domain Controller may disable compressor operation, high-speed fan rotation or other automatic adjustment functions dependent on temperature thresholds.
• Dashboard warning information: "Air conditioning fault", "Refrigerant sensor error" and other diagnostic message prompts may appear on the central control screen or instrument cluster.
• Reduced cooling performance: In the set driving mode, the air outlet airflow volume or cold air output intensity may fail to reach expected values, or automatically switch to heat dissipation mode under high-temperature conditions.

Core Fault Cause Analysis

According to diagnostic data, physical and logical factors leading to triggering of this fault code can be divided into the following three dimensions:

1. Hardware Component Failure: That is "Refrigerant Temperature Sensor 2 Failure". The thermal resistor element inside the sensor may suffer from material aging, performance drift or physical damage due to long-term high-temperature environment, causing it to be unable to output normal analog voltage signals.
2. Line and Physical Connection Abnormalities: That is "Wiring Harness or Connector Faults". Wires responsible for signal transmission may have open circuits, short circuits or be chewed off by rodents; sensor plugs may have pin backout, oxidation corrosion, loosening or excessive contact resistance physical connection problems, leading to circuit loop opening.
3. Internal Logic Operation Errors in Controller: That is "Right Domain Controller Fault". The ADC (Analog-to-Digital Converter) circuit inside the control unit may be damaged, or its algorithm for processing input signals has deviations, mistakenly interpreting normal signals as high voltage open circuit states.

Technical Monitoring and Triggering Logic

The generation of this fault code follows a strict status monitoring strategy, with its judgment process relying on specific electrical parameter thresholds and vehicle operating conditions:

• Monitoring Target: System continuously monitors the "Refrigerant Temperature Sensor 2" ground output voltage signal. Under normal conditions, this voltage value should fluctuate within a specific resistance range with temperature changes; under abnormal conditions it manifests as voltage locking or jumping to baseline power high level.
• Voltage Threshold Judgment: The core electrical standard for fault judgment is that the control unit detects the sensor output voltage exceeding $> 4.95V$. When input voltage is higher than this limit, the system judges it as an open circuit signal (Open Circuit), because in open circuit state the sensor terminal voltage is usually pulled up to close to power voltage level.
• Trigger Conditions: This monitoring logic is only effectively activated when "Start switch is placed in ON position". Only under static self-check mode where ignition system is connected but engine is not running, will the control unit initialize scan and voltage comparison for this sensor loop, once detection meets above voltage condition, immediately write fault code and light up relevant warning lamps.

Cause Analysis According to diagnostic data, physical and logical factors leading to triggering of this fault code can be divided into the following three dimensions:

1. Hardware Component Failure: That is "Refrigerant Temperature Sensor 2 Failure". The thermal resistor element inside the sensor may suffer from material aging, performance drift or physical damage due to long-term high-temperature environment, causing it to be unable to output normal analog voltage signals.
2. Line and Physical Connection Abnormalities: That is "Wiring Harness or Connector Faults". Wires responsible for signal transmission may have open circuits, short circuits or be chewed off by rodents; sensor plugs may have pin backout, oxidation corrosion, loosening or excessive contact resistance physical connection problems, leading to circuit loop opening.
3. Internal Logic Operation Errors in Controller: That is "Right Domain Controller Fault". The ADC (Analog-to-Digital Converter) circuit inside the control unit may be damaged, or its algorithm for processing input signals has deviations, mistakenly interpreting normal signals as high voltage open circuit states.

Technical Monitoring and Triggering Logic

The generation of this fault code follows a strict status monitoring strategy, with its judgment process relying on specific electrical parameter thresholds and vehicle operating conditions:

• Monitoring Target: System continuously monitors the "Refrigerant Temperature Sensor 2" ground output voltage signal. Under normal conditions, this voltage value should fluctuate within a specific resistance range with temperature changes; under abnormal conditions it manifests as voltage locking or jumping to baseline power high level.
• Voltage Threshold Judgment: The core electrical standard for fault judgment is that the control unit detects the sensor output voltage exceeding $> 4.95V$. When input voltage is higher than this limit, the system judges it as an open circuit signal (Open Circuit), because in open circuit state the sensor terminal voltage is usually pulled up to close to power voltage level.
• Trigger Conditions: This monitoring logic is only effectively activated when "Start switch is placed in ON position". Only under static self-check mode where ignition system is connected but engine is not running, will the control unit initialize scan and voltage comparison for this sensor loop, once detection meets above voltage condition, immediately write fault code and light up relevant warning lamps.