AU
C050576

This DTC indicates the IPB (Integrated Intelligent Braking System) detects a correlation plausibility fault in the left front wheel speed sensor signal — Seal 6 EV

Braking System

This DTC indicates the IPB (Integrated Intelligent Braking System) detects a correlation plausibility fault in the left front wheel speed sensor signal.

Specifically, the frequency or amplitude of the sensor pulse signal logically conflicts with the actual vehicle motion state, the other three wheel speed signals, or the longitudinal acceleration sensor data, failing the system plausibility check algorithm.

This fault typically indicates intermittent sensor signal interruption, electromagnetic interference, magnetic ring (magnetic encoder) demagnetization, or out-of-tolerance mechanical installation clearance.

These conditions prevent the ABS/ESC from accurately identifying the actual left front wheel speed, triggering the ABS warning light and ESC OFF light, and degrading the automatic emergency braking system.

The C050576 fault code on the Seal 6 EV indicates a plausibility fault in the left front wheel speed sensor signal. This is a medium-severity issue that can trigger ABS and ESC warnings and reduce braking assistance functions. Common causes include an unstable sensor signal or incorrect sensor-to-magnetic ring air gap from loose or damaged mounting parts. Visit an authorised dealer for diagnosis and repair. Typical repair cost data is available from recorded cases.
5
Cases Logged
5
Causes
Likely Causes — Seal 6 EV
  • 1Open or short circuit in the left front wheel speed sensor internal coil (magnetic induction type), or Hall element signal drift, causing unstable output signal amplitude.
  • 2Deformed sensor mounting bracket, loose retaining bolts, or missing shim causing the air gap between the sensor and magnetic ring to exceed the standard range (0.3-1.2mm).
  • 3Heavy accumulation of iron filings or mud on the surface of the wheel hub bearing magnetic encoder (magnetic ring), physical damage, or demagnetization.
  • 4The sensor wiring harness insulation is chafed through at a suspension movement interference point, or oxidation or looseness at terminals B05/B06 of the IPB control unit connector interrupts signal transmission.
  • 5Inconsistent tyre sizes (e.g., installing a non-full-size spare tyre) or severely low left front tyre pressure, causing the wheel speed difference to continuously exceed the system calibration threshold.
What To Do
  • 1
    Connect the VDS2000/VDS3100 diagnostic tool, read the C050576 freeze frame data, and record the vehicle speed, left front wheel speed, steering wheel angle, and longitudinal acceleration at the time of the fault. Check for other accompanying sub-codes in the C050500-C050599 series.
  • 2
    Raise the vehicle off the ground. Visually inspect the left front wheel speed sensor wiring harness for wear or stretching at the steering knuckle and lower control arm retaining clips. Inspect the connector waterproof seal for aging.
  • 3
    Remove the left front wheel speed sensor and measure the sensor resistance using a multimeter: for electromagnetic types, the standard value is 1.0-1.5kΩ (20°C); for Hall effect types, check the supply voltage (12V/5V) and signal output. Check the sensor tip for metal debris.
  • 4
    Clean the magnetic encoder surface. Check the magnetic ring for cracks, missing teeth, or demagnetization (measure the magnetic field strength using a gauss meter). Check if the wheel hub bearing axial/radial play exceeds the limit.
  • 5
    Measure the installation gap between the sensor and the magnetic ring using a feeler gauge. If the gap exceeds 1.2 mm, replace the mounting bracket or adjust the shims. Reinstall the sensor and tighten to the specified torque (usually 8-12 N·m).
  • 6
    Perform a dynamic test: Shift to D and slowly rotate the wheels. Read the data stream to verify the left front wheel speed signal synchronizes with the other wheel speeds without spikes. Perform a road test to verify ABS/ESC function recovery, then clear the fault code.
  • 7
    If the above checks are normal, measure continuity and insulation between the IPB control unit terminals and the sensor wiring harness. If necessary, update the IPB software to the latest version or replace the IPB assembly.
Real-World Cases
BYD DTC AI Analysis

Worn sensor wiring harness causing intermittent fault — Song PLUS DM-i

✓
ABS warning light illuminated intermittently when driving on rough roads. Scan tool read C050576 as an intermittent fault. Inspection revealed the left front wheel speed sensor wiring harness had chafed through the insulation at the lower control arm mounting point, causing the copper conductors to intermittently short to ground. Repaired the damaged harness, rerouted the wiring with corrugated tube protection, and secured it with cable ties clear of moving parts. Fault resolved.
BYD DTC AI Analysis

Metal debris on reluctor ring surface caused erratic signal

✓
The owner reported premature ABS activation during braking. Inspection found the left front wheel hub magnetic encoder had accumulated significant brake dust and metallic road debris, causing wheel speed sensor signal amplitude fluctuations. Cleaned the magnetic ring and test drove, but fault codes still appeared intermittently. Further inspection revealed the sensor tip was worn. Replaced the left front wheel speed sensor and thoroughly cleaned the magnetic ring. Fault resolved.
BYD DTC AI Analysis

Excessive wheel bearing play caused the reluctor ring to scrape

✓
The ESC warning light suddenly illuminated at highway speed. Live data revealed the left front wheel speed signal intermittently dropping to zero. Disassembly revealed the left front wheel hub bearing radial clearance exceeded specifications (>0.1 mm), causing dynamic interference between the magnetic ring and sensor. The sensor tip was scratched. Replaced the left front wheel hub bearing assembly (including magnetic ring) and wheel speed sensor. Fault eliminated.
BYD DTC AI Analysis

Non-full-size spare tyre caused wheel speed variance to exceed limits

✓
Replaced the left front tyre with a space-saver spare and drove. Multiple system warnings lit up on the dash. Scanner logged C050576 rationality fault. Found the spare diameter ~6% smaller than the standard tyre, causing the left front wheel speed to read consistently higher than the others. Fitted a standard-spec tyre, adjusted pressure to 2.5 bar, cleared the fault codes. System returned to normal.
BYD DTC AI Analysis

IPB software calibration error caused false alarm.

✓
During new vehicle PDI, found active fault C050576. Sensor and wiring harness checked normal; signal waveform standard. Technical service bulletin revealed IPB software V1.2 on this batch has an overly sensitive wheel speed rationality algorithm. Upgraded IPB control unit software to V1.5, performed sensor calibration, and eliminated 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.