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C050E00

DTC C050E00 indicates the IPB (Intelligent Integrated Braking System) or ABS module detects an abnormal short circuit to vehicle ground (GND) in the left rear wheel speed sensor (WSS) power supply circuit (typically the 12V supply line) — Seal U

Braking System

DTC C050E00 indicates the IPB (Intelligent Integrated Braking System) or ABS module detects an abnormal short circuit to vehicle ground (GND) in the left rear wheel speed sensor (WSS) power supply circuit (typically the 12V supply line).

This supply circuit provides the operating voltage for the Hall-effect or magnetic wheel speed sensor.

When a short to ground occurs, the power driver circuit inside the ABS module detects overcurrent or a voltage drop to nearly 0V, triggering the protection mechanism and storing the fault code.

This fault causes a missing or abnormal left rear wheel speed signal, forcing active safety functions such as ABS, ESC, TCS, and Automatic Emergency Braking (AEB) into fail-safe mode (conventional braking).

The instrument cluster illuminates multiple warning lamps, including ABS, ESC, and EBD.

This severely compromises driving safety and creates a risk of wheel lock-up, especially on slippery roads or during emergency braking.

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Cases Logged
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Causes
Likely Causes — Seal U
  • 1Damaged or aged insulation on the left rear wheel speed sensor wiring harness rubs against metal components such as the body side member, suspension bracket, or wheel arch liner during driving, causing the power wire to short to ground.
  • 2Short circuit inside the wheel speed sensor body between the power supply pin and the sensor housing or ground pin (usually resulting from water ingress due to sensor seal failure, internal coil burnout, or circuit board breakdown).
  • 3Water enters the sensor connector (located at the left rear fender or chassis wiring harness junction) due to driving through water, high-pressure washing, or an aging sealing ring, causing an electrolytic short circuit or corrosion-induced continuity between the power and ground terminals inside the connector.
  • 4A breakdown short circuit in the internal power drive circuit of the ABS/IPB control module (such as a MOSFET or smart power chip) causes the output port to continuously conduct to ground.
  • 5Accident repairs, chassis modifications, or improper wiring harness securing pinches or crushes the wiring harness, or causes retaining clips to loosen, allowing the harness to rub and wear against rotating components (such as the half shaft or brake disc dust shield).
What To Do
  • 1
    Connect the VDS or a dedicated diagnostic tool and read the freeze frame data for DTC C050E00. Record key parameters at the time of the fault, such as vehicle speed, voltage, and temperature. Clear the fault code and perform a road test to confirm if the fault is continuous.
  • 2
    Raise the vehicle and remove the left rear wheel. Visually inspect the wheel speed sensor for physical damage. Specifically check the sensor connector (usually located near the shock absorber or body harness connection) for water ingress, terminal corrosion, looseness, or damaged wiring insulation.
  • 3
    Disconnect the left rear wheel speed sensor connector. Use a multimeter to measure the resistance between the sensor-side power pin and body ground. Normal resistance is greater than 10MΩ (open circuit). A resistance less than 1Ω confirms a short circuit. Simultaneously measure the resistance to ground at the corresponding pin on the ABS module side to determine whether the short circuit is in the wiring harness or inside the module.
  • 4
    If the wiring harness shorts to ground, strip the harness sleeve in sections from the left rear wheel hub to the ABS module (usually located in the engine compartment or cabin firewall). Closely inspect the sections passing through body panel holes, retaining clips, and areas adjacent to suspension components to locate the damaged insulation. After repair, wrap the affected area with two layers of waterproof insulating tape or heat-shrink tubing.
  • 5
    If the wiring harness is normal, measure the resistance between the power and ground pins on the wheel speed sensor itself (normally open circuit or high resistance). If the resistance is abnormally low (<100Ω), the sensor has an internal short circuit. Replace the left rear wheel speed sensor (BYD part numbers usually start with SC- or HA-).
  • 6
    If the sensor and wiring harness are normal, measure the resistance between the corresponding power supply pin of the ABS/IPB module connector and ground. A short circuit indicates an internal module fault. Replace the IPB assembly or ABS control unit (perform coding and bleeding procedures).
  • 7
    After completing the repair, reconnect all connectors, clear the fault code using the diagnostic tool, and perform a dynamic test: drive straight at 20-40km/h and verify in the data stream that the left rear wheel speed signal synchronizes with the right rear and front wheel speeds; perform an emergency braking test to confirm normal ABS operation and verify the fault code does not recur.
Real-World Cases
BYD DTC AI Analysis

Seal 6 DM-i left rear wheel speed sensor harness chafed and shorted to ground

✓
While driving, the ABS and ESC warning lights suddenly lit up on the dash with a 'check brake system' alert. The scan tool pulled DTC C050E00 (left rear wheel speed sensor signal circuit short to ground). Inspection found the left rear wheel speed sensor wiring harness retaining clip had come loose where it passes through the body rail, allowing the harness to chafe against the rear suspension lower control arm. Prolonged friction damaged the insulation, exposing the copper core and shorting it to the metal bracket. Repair: Cut out the damaged section and soldered in a repair wire. Rerouted the harness and protected it with corrugated tubing and waterproof tape. Repositioned the retaining clip to prevent interference with moving parts. Replaced the wheel speed sensor, cleared the fault codes and road tested. Wheel speed signal returned to normal.
Original source ↗
BYD DTC AI Analysis

Song PLUS DM-i sensor connector corroded and shorted after water ingress

✓
After driving through flood water, the dashboard displayed a brake system fault and the ABS failed. Scanned DTCs C050E00 and C050C00 (wiring harness fault). Removed the left rear wheel speed sensor connector (located behind the left rear wheel arch liner) and found substantial muddy water deposits inside. Electrolytic corrosion between the power pin (normally red wire) and ground pin (black wire) had created green copper oxide, shorting the pins. Repair: Thoroughly cleaned the connector pins with electrical contact cleaner and sandpaper, replaced the waterproof seal, and applied silicone sealant at the connector mating surface to improve waterproofing. Measured sensor supply voltage at 12V (normal). Cleared the fault codes—fault resolved. Inspect the seals on other chassis wiring harness connectors.
Original source ↗
BYD DTC AI Analysis

Internal short circuit in wheel speed sensor body caused intermittent fault

✓
Cold starts are normal, but the ABS light comes on after roughly 10 minutes of driving. Shutting off and restarting the engine clears the fault, but it returns. Scanner shows DTC C050E00. Freeze frame data indicates the left rear wheel speed was 0 km/h when the fault triggered, while the other wheels read normally. Static resistance tests on the sensor were normal, but hot-state testing (using a heat gun to simulate operating temperature) showed a sharp resistance drop between power and ground. Diagnosis: thermal fatigue failure of the internal coil insulation. Repair: Replace the left rear wheel speed sensor (use the correct type—variable reluctance or Hall effect; Song PLUS DM-i usually has two-wire Hall or variable reluctance sensors). Adjust the sensor-to-tone ring gap to 0.3–1.2 mm during installation and apply grease to prevent seizing.
Original source ↗
BYD DTC AI Analysis

Internal drive circuit fault in IPB integrated brake module

✓
Repair case reference: After confirming the left rear wheel speed sensor, wiring harness, and connectors were normal, measured a continuous short to ground (resistance <1Ω) between the IPB (Integrated Power Brake) module’s left rear wheel speed sensor power supply terminal (typically marked RR+ or Vbat_RL) and ground. The short persisted at the module terminal even with the harness disconnected. Diagnosed as internal power management chip (LDO or MOSFET) breakdown in the IPB module. Fix: Replace the entire integrated brake unit (IPB is a complete assembly; part number varies by model—for example, the Song PLUS DM-i requires the IPB assembly). Post-replacement, perform IPB coding and configuration, longitudinal acceleration sensor calibration, brake line bleeding, and ESC function testing using a diagnostic tool. Fault resolved.
Other Seal U 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.B110913DTC B110913 indicates an open signal circuit for the PM2.5 rapid detector (in-cabin air quality sensor). This sensor typically mounts inside the air conditioning system intake duct. It monitors in-cabin PM2.5 concentration in real time and provides data to the automatic air conditioning system for intelligent control of the air purification function. The BYD diagnostic protocol uses sub-code '13' to specifically indicate an open signal circuit. Although this fault theoretically affects a comfort feature, BYD Qin series vehicles classify it as a Level 3 (severe) fault. This classification occurs because the air conditioning system interacts with the battery thermal management system (e.g., monitoring battery cooling intake air quality). The fault can disable the automatic air conditioning mode and prevent the air purification function from operating. In extreme cases, it affects the battery compartment intake air quality assessment, triggering the 'repair immediately' strategy.B110AThis DTC indicates interrupted CAN bus communication or abnormal data between the air conditioning control unit (ACU) and the PM2.5 air quality sensor. The PM2.5 sensor monitors particulate concentration inside and outside the vehicle and provides the basis for purification control in the automatic air conditioning system. The ACU triggers this fault if it fails to receive a valid CAN message from the sensor within the specified period (usually 100-500 ms), if message verification fails, or if the signal frame times out. Although this fault does not affect vehicle driving safety, it disables the automatic air purification function. The air conditioning system cannot automatically switch between recirculation and fresh air modes or activate the air purification mode based on air quality. A persistent fault may restrict the thermal management strategy.
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.