AU
C050300

DTC C050300 indicates a short to battery positive (B+) in the left front wheel speed sensor (WSS) power supply circuit — Seal 6 EV

Braking System

DTC C050300 indicates a short to battery positive (B+) in the left front wheel speed sensor (WSS) power supply circuit.

Normally, the IPB (Integrated Power Brake) supplies 5V or 12V to the wheel speed sensor (depending on sensor type).

A "short to battery" condition means the power supply line shorts to a vehicle constant power circuit, or the internal sensor power terminal breaks down to the signal or ground terminal.

This causes the control unit to detect an abnormally high voltage (approximately 12V battery voltage).

This prevents the IPB from correctly reading the left front wheel speed signal, triggers the safety protection mechanisms of systems such as ABS, ESP, and Automatic Emergency Braking, and disables the related functions.

The C050300 fault code on the Seal 6 EV indicates a high-severity short to battery positive in the left front wheel speed sensor power supply circuit. This can stop ABS, ESP, and emergency braking functions from working correctly. Common causes include damaged sensor wiring touching a power wire or an internal sensor short. The recommended fix is to visit an authorised dealer for diagnosis and repair. Typical repair cost data is available from recorded cases.
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Cases Logged
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Causes
Likely Causes — Seal 6 EV
  • 1Damaged insulation on the left front wheel speed sensor harness contacts body power wires (such as the headlight power supply or horn wires), causing a short circuit.
  • 2Sensor internal power supply circuit breakdown causing a short circuit between the power terminal and the housing or signal wire.
  • 3Water ingress, corrosion, or bent pins at the wheel speed sensor connector causing the power supply terminal to short to an adjacent power terminal.
  • 4After front-end collision repair, improper wiring harness routing or detached retaining clips cause the wiring harness to rub against sharp edges and sustain damage.
  • 5IPB control unit internal power supply drive circuit fault, causing an abnormal increase in output voltage.
What To Do
  • 1
    Connect the VDS diagnostic tool, read and record the freeze frame data for DTC C050300, and confirm the vehicle speed and voltage status when the fault occurred.
  • 2
    Switch off the ignition, disconnect the left front wheel speed sensor connector, and check the connector terminals for signs of corrosion, deformation, or water ingress.
  • 3
    Turn the ignition switch to the ON position (do not start). Use a multimeter to measure the voltage between the sensor harness connector power supply terminal and ground. If the reading is 12V (battery voltage), this confirms a short to power. Normal voltage is 5V or 12V (depending on vehicle configuration, but must be stable and within sensor specifications).
  • 4
    Disconnect the IPB control unit connector. Measure the continuity between the left front wheel speed sensor power supply circuit and the IPB. Measure the insulation resistance between this circuit and the power supply (B+). The resistance must be greater than 10 MΩ.
  • 5
    Check the sensor body resistance. The normal range is usually 1.0-1.5 kΩ (magnetic induction type) or per Hall sensor specifications. Replace the sensor if the resistance is abnormal.
  • 6
    If the wiring harness has a short circuit, repair the damaged wiring (re-wrap or replace the harness section). If the sensor is faulty, replace it with a genuine wheel speed sensor. Clear the fault code and perform a road test to confirm normal ABS operation.
Real-World Cases
BYD DTC AI Analysis

Left front wheel speed sensor harness worn through, short to power

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Vehicle: Song PLUS DMi 2022 model, 12,000 km. Symptoms: ABS and ESP warning lights constantly on; DTC C050300. Diagnosis: Lifted the vehicle and found the left front wheel speed sensor harness chafed through at the steering knuckle mounting point. The damage exposed internal copper wires that were touching the headlight power supply wire, causing a 12V short. Measured 12.5V at the sensor supply (abnormal). Fix: Soldered the damaged harness and insulated it with double-layer heat shrink tubing. Re-routed and secured the harness to prevent interference with steering components. Replaced the left front wheel speed sensor (possibly damaged by the short). Fault cleared.
BYD DTC AI Analysis

Water in the sensor connector caused a power supply short circuit.

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Vehicle: BYD Han EV. C050300 DTC set after driving through water. Found clear water staining and corrosion inside the left front wheel speed sensor connector. The power supply terminal had shorted to an adjacent constant-power terminal (possibly for the steering assist light). Cleaned and dried the connector, applied conductive grease, measured normal insulation, and cleared the fault. Recommend checking front wheel arch sealing.
BYD DTC AI Analysis

Aftermarket headlight modification damaged the wheel speed sensor wiring

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Vehicle: BYD Qin PLUS DMi. During a DIY LED headlight install, the owner secured the wiring with a clip that pierced the left front wheel speed sensor harness, shorting the sensor power feed to the headlight supply. The ABS warning light lit intermittently while driving. The scanner read C050300. Supply voltage changed with the headlight switch position. Repaired the harness and rerouted the wiring to resolve the fault.
Other Seal 6 EV Fault Codes
B1108For the BYD Song MAX (2017–2019), DTC B1108 indicates a short circuit in the PM2.5 air quality detection module (dust sensor) or its wiring harness. The sensor uses laser scattering to detect in-cabin and outside PM2.5 concentrations and transmits data to the HVAC ECU via the LIN bus or an analog signal. Short circuit conditions include: 1) Sensor power supply wire (+5V/+12V) shorted to ground 2) Signal wire shorted to power or ground 3) Short circuit in the sensor's internal photoelectric detection circuit This fault prevents the automatic climate control from switching between fresh air and recirculation based on air quality. The system enters fail-safe mode (typically forced recirculation). Severe short-circuit current can destroy the HVAC ECU sampling circuit. The system classifies this as a Level 3 severe fault and restricts vehicle operation to prevent electrical fires or controller damage. For other BYD models (such as the Qin EV, E5, and Song DM), B1108 indicates a driver-side sunload sensor fault, reflecting differences in DTC definitions across models.B110811This DTC indicates a short circuit in the air conditioning system PM2.5 air quality sensor (rapid detector). Specifically, abnormal continuity exists between the sensor power supply circuit or signal output circuit and body ground or battery positive. This causes the control module (ACU/air conditioning controller) to detect abnormal current or a voltage signal outside the valid range (typically 0V or supply voltage). The PM2.5 sensor monitors internal and external particulate concentrations, providing the data the automatic air conditioning system uses to switch between fresh air and recirculation modes. A short circuit disables the air quality monitoring function. This fault may force the air conditioning system into recirculation protection mode and trigger related thermal management system faults, as the air conditioning system acts as a key actuator in vehicle thermal management. In severe cases, the short circuit current can damage the internal sampling circuit of the air conditioning controller or overheat the wiring harness.B1109DTC B1109 indicates an open circuit in the communication line between the air conditioning system PM2.5 air quality sensor (dust concentration sensor) and the air conditioning control unit (AC ECU), or an open circuit within the sensor internal circuitry. Typically located in the air conditioning intake duct, this sensor monitors real-time PM2.5 particle concentration inside and outside the vehicle. It provides data to the automatic air conditioning system for intelligent switching between fresh air and recirculation modes and for controlling the air purification device. During an open circuit fault, the AC ECU cannot receive the air quality signal, triggering the system fail-safe mode. Symptoms typically include failure of the automatic recirculation function, abnormal air purification indicator light operation, or abnormal air quality data displayed on the air conditioning panel. Severe cases may compromise the cabin environment control strategy, but do not directly affect vehicle driving safety.B1737DTC B1737 indicates the Supplemental Restraint System (SRS) detected abnormal continuity between the right middle-row side airbag squib circuit (typically the second-row right seat side airbag or right curtain airbag) and the vehicle power supply (B+, battery positive). The SRS ECU monitors the airbag inflator resistance via an internal current source (normal resistance: 2.0–3.0 Ω). If the ECU detects the voltage across the inflator circuit remaining close to battery voltage (>5 V and approaching 12 V) instead of the expected low potential or floating state, it identifies a short to power. This fault prevents the airbag from deploying normally during a collision because the short circuit bypasses the firing current. In extreme cases, abnormal current can cause unintended deployment, posing a severe safety hazard.B173BDTC B173B indicates an abnormal electric A/C compressor speed feedback signal or a communication fault between the compressor controller and the motor. In BYD new energy models (e.g., Tang, Song, Qin, and Yuan series), this DTC belongs to the HVAC subsystem within the Body Control system and specifically involves the electric compressor closed-loop control circuit. The ECU sets this DTC when the compressor controller (IPM) fails to receive a valid pulse signal from the Hall speed sensor for more than 3 continuous seconds, or when the deviation between the detected actual speed and the target commanded speed exceeds the calibrated threshold (typically >500 rpm). This fault forces the A/C system into fail-safe mode and stops compressor operation. Symptoms include a complete lack of cooling, intermittent cooling, or a sharp decrease in cooling performance. The instrument cluster A/C warning lamp may also illuminate. Prolonged operation with this fault can degrade high-voltage system insulation or cause controller overcurrent damage.
Common problems reported for Seal 6 EV →Seal 6 EV overview →
Data confidence: Official This information is for reference only. Always consult a qualified technician for diagnosis and repair. Do not attempt high-voltage system repairs yourself.