AU
C050A00

DTC C050A00 indicates the IPB (Intelligent Integrated Braking System) ECU detects the air gap between the right front wheel speed sensor (WSS) and the signal tone ring exceeds the calibrated tolerance range (typically 0 — Qin Plus

Braking System

DTC C050A00 indicates the IPB (Intelligent Integrated Braking System) ECU detects the air gap between the right front wheel speed sensor (WSS) and the signal tone ring exceeds the calibrated tolerance range (typically 0.3-1.2mm), or the sensor signal amplitude/phase exhibits intermittent erratic characteristics.

This is a plausibility fault, distinct from a direct short or open circuit.

The IPB system uses an active Hall-effect wheel speed sensor highly sensitive to the installation air gap.

An excessive gap attenuates the signal, while an insufficient gap causes the sensor head to rub against the tone ring.

The ECU sets this fault when algorithmic compensation cannot verify wheel speed signal reliability.

This fault degrades or disables ABS, ESP, TCS, and Automatic Emergency Braking (AEB) functions.

In severe cases, it illuminates the brake system warning lamp continuously.

The C050A00 fault code on the Qin Plus indicates a medium-severity issue with the right front wheel speed sensor signal, usually due to an incorrect air gap to the tone ring. Common causes include a loose or dirty sensor mounting area, or wear/play in the right front wheel hub bearing. ABS, ESP, TCS, and AEB may be reduced or disabled. Visit an authorised dealer for inspection and repair. Typical repair cost data is available.
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Cases Logged
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Causes
Likely Causes — Qin Plus
  • 1Loose wheel speed sensor mounting, or mud, sand, or foreign objects in the mounting hole, causing the actual air gap to deviate from the standard value.
  • 2Excessive axial play or wear in the right front wheel hub bearing causes axial displacement of the integrated signal tone ring (magnetic encoder ring), altering the air gap.
  • 3Physical damage to the wheel speed sensor head from bottoming out, flying stones, or long-term wear, affecting the magnetic field distribution.
  • 4Signal tone ring (magnetic encoder ring) deformed, damaged, or covered with a heavy buildup of iron filings/mud, causing signal distortion that the system misdiagnoses as an air gap fault.
  • 5Installing a non-genuine wheel hub bearing or sensor with component dimensional tolerances that do not meet IPB system accuracy requirements.
What To Do
  • 1
    Use VDS2000 or the BYD dedicated diagnostic tool to read the complete fault codes, confirm if the fault is current (Present), and record freeze frame data (vehicle speed, temperature, etc.).
  • 2
    Raise the vehicle. Check the right front wheel speed sensor exterior and wiring harness connector for damage or water ingress. Check the sensor tip for wear marks or attached foreign matter.
  • 3
    Remove the right front wheel speed sensor. Use a feeler gauge or dedicated air gap measuring tool to measure the air gap between the sensor tip and the tone ring (standard value: 0.3-1.2 mm). Rotate the wheel hub one full turn and measure at multiple points to verify the air gap is uniform.
  • 4
    Check the wheel hub bearing axial play: Grasp the top and bottom of the tire with both hands and push and pull to check for obvious play. If present, replace the wheel hub bearing assembly.
  • 5
    Check the signal tone ring: Inspect the magnetic encoder ring for cracks, deformation, or missing teeth. Clean iron filings and dirt from the tone ring surface.
  • 6
    If the air gap is abnormal but the bearing and tone ring are normal, check the sensor mounting seat for deformation. Replace the sensor if necessary (Note: Some models use a sensor shim; verify the shim is intact).
  • 7
    After installing the new sensor or bearing, remeasure the air gap to verify it is within the standard range, and tighten the sensor retaining bolt (typical torque: 8-12 N·m).
  • 8
    Clear the fault code, calibrate the wheel speed sensor (if the repair manual requires it), perform a road test (including straight-line driving and turning), and verify the IPB system operates normally.
Real-World Cases
BYD DTC AI Analysis

Dolphin ESP false trigger: Bearing wear increased air gap

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Symptoms: The BYD Dolphin’s ESP warning light illuminated intermittently while driving, with a kick-back sensation through the brake pedal. Scan tool retrieved DTC C050A00 (Right Front Wheel Speed Sensor Air Gap Abnormal). Diagnosis: Raised the vehicle and inspected the right front wheel speed sensor; it appeared undamaged. Measured the sensor air gap and found a maximum of 1.8 mm (exceeding specification). The wheel bearing also showed noticeable axial play—0.5 mm of vertical movement when pushing the tire up and down. The worn hub bearing caused the integrated ABS tone ring to sink, creating an uneven air gap. Repair: Replaced the right front wheel hub bearing assembly (including the ABS tone ring). Reinstalled the OEM sensor and adjusted the air gap to 0.6 mm. Cleared the fault codes and road-tested; ESP function returned to normal.
BYD DTC AI Analysis

Signal plate deformed after Yuan Plus bottomed out

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Symptoms: Right front wheel struck a curb. Dashboard displayed 'Braking System Fault'. DTCs C050A00 and C003400 retrieved (right front wheel speed sensor signal fault). Diagnosis: Removed right front wheel. Found slight scrape marks on the wheel speed sensor head and localized denting on the tone ring (magnetic ring), causing periodic air gap variation during rotation. Resolution: Replaced right front wheel speed sensor and wheel hub bearing unit together (tone ring is integrated with the bearing). Set air gap to workshop manual specifications during installation. Fault resolved.
BYD DTC AI Analysis

BYD Seal intermittent fault: Silt in mounting hole causing abnormal air gap

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Symptoms: After driving through water, the BYD Seal's ESP warning light flashed intermittently. The scanner logged intermittent DTC C050A00. Diagnosis: Checked the sensor connector for water ingress; none found. Measured sensor resistance; normal. Removed the sensor and found heavy sediment buildup in the mounting bore preventing full seating, resulting in an air gap exceeding specification. After cleaning and reinstalling, the air gap remained slightly over the upper limit at 1.3mm. Resolution: Thoroughly cleaned the mounting seat. Installed a new sensor with adjustment shim. Used a feeler gauge to check multiple points and verified air gap within 0.3-1.2mm. Cleared the DTC; the fault has not recurred.
BYD DTC AI Analysis

Qin PLUS DM-i Aftermarket Bearing Dimensional Deviation

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Symptoms: Following replacement of the right front wheel hub bearing at an independent workshop, the BYD Qin PLUS DM-i showed constant ABS/ESP warning lights and set DTC C050A00. Diagnosis: Comparing the old and new bearings revealed the aftermarket unit's magnetic encoder ring position deviated approximately 0.5 mm axially from the OEM part. This left the sensor air gap too small after installation (measured at 0.2 mm), saturating the sensor signal. Solution: Installed an OEM wheel hub bearing assembly, adjusted the air gap to specification, calibrated the wheel speed sensor with a diagnostic tool, and cleared the fault.
Other Qin Plus 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.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.B110BDTC B110B indicates a fault in the internal air pump (sampling pump) of the PM2.5 air quality detector. This pump draws cabin or outside air into the PM2.5 sensor detection chamber, enabling the laser scattering sensor to measure real-time particulate matter concentration. The air conditioning controller (or BCM) sets this DTC upon detecting an open or short circuit in the pump drive circuit, or abnormal current caused by a seized pump motor. This fault disables the "Green Clean" system, causes the instrument cluster air quality display to read abnormally or disappear, and disables the automatic fresh air/recirculation switching function. It does not affect the vehicle powertrain or core thermal management functions.B173A1ADTC B173A1A indicates the right middle-row side airbag (typically located on the side of the right second-row seat or inside the C-pillar trim panel) igniter circuit resistance measures 0 Ω. In the Supplemental Restraint System (SRS), normal airbag igniter resistance ranges between 2.0 and 5.0 Ω. A resistance of 0 Ω indicates a short to ground or a short between circuit wires, preventing the Airbag Control Unit (ACU) from establishing a normal monitoring circuit. This safety-critical fault prevents the airbag from deploying during a collision, continuously illuminates the instrument panel SRS warning lamp, and may force the entire airbag system into fail-safe mode.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 Qin Plus →Qin Plus 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.