AU
C050B76

DTC C050B76 indicates the IPB (Intelligent Integrated Braking System) detects a correlation fault in the right front wheel speed sensor signal — Atto 8

Braking System

DTC C050B76 indicates the IPB (Intelligent Integrated Braking System) detects a correlation fault in the right front wheel speed sensor signal.

This fault does not indicate a simple signal loss (open circuit).

Instead, the sensor pulse signal output logically mismatches actual vehicle dynamics (e.g., other wheel speeds, vehicle speed, acceleration, yaw rate), or the signal characteristics (frequency, amplitude, duty cycle) exceed calibrated thresholds.

The IPB algorithm compares the correlation of all four wheel speed sensors.

The system sets this code when the right front signal differs excessively from the other wheel speeds, exhibits erratic signal jumps, or experiences an intermittent fault in the sensor power supply or ground circuit.

This fault directly affects the Anti-lock Braking System (ABS), Electronic Stability Control (ESC), Automatic Emergency Braking (AEB), and energy recovery functions.

It may increase braking distance or cause abnormal brake pedal feel.

The C050B76 fault code on the Atto 8 indicates a correlation fault in the right front wheel speed sensor signal. Severity is medium because it can affect ABS, ESC, AEB, and energy recovery, possibly increasing braking distance or causing unusual pedal feel. Common causes include a degraded sensor or an incorrect air gap from a loose bolt, bracket damage, or bearing wear. Visit an authorised dealer for diagnosis and repair. Typical repair cost data is available.
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Cases Logged
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Causes
Likely Causes — Atto 8
  • 1Right front wheel speed sensor component degradation or an internal coil inter-turn short circuit causes insufficient output signal amplitude or waveform distortion. Signal quality degrades particularly at high temperatures or high wheel speeds.
  • 2Abnormal air gap between the sensor and magnetic encoder ring (tone ring) (greater than 1.2 mm or less than 0.3 mm). Common causes include a loose sensor retaining bolt, a deformed bracket, or bearing wear causing axial hub play.
  • 3Damage to the magnetic encoder ring in the right front wheel hub unit (demagnetization, cracks, or attached iron filings) causes uneven magnetic flux changes, resulting in signal noise or missing tooth signals.
  • 4Intermittent sensor wiring harness fault, including poor contact at IPB control unit connector pin 26 (signal), pin 25 (power supply), or the body ground circuit, and wiring harness wear causing a short circuit during suspension movement.
  • 5Inconsistent tyre specifications or severely unbalanced tyre pressures cause a systematic deviation between the actual speed of the right front tyre and the other tyres, triggering an IPB correlation check failure.
What To Do
  • 1
    Use a diagnostic tool to read freeze frame data. Confirm the vehicle speed, wheel speed values, and IPB supply voltage at the time of the fault. Check for accompanying fault codes (e.g., C050A00, U0121). Clear the fault codes and perform a road test. Monitor the right front wheel speed data stream for sudden fluctuations or loss of synchronization with the other wheel speeds.
  • 2
    Raise the vehicle and visually inspect the right front sensor. Verify the mounting bolt torque (standard 8-12 N·m). Check the wiring harness for stretching at the steering lock positions. Measure the sensor resistance (standard value 1.5-2.5 kΩ at 20°C). Measure the sensor supply voltage (12 V ± 0.5 V with ignition ON).
  • 3
    Remove and inspect the right front wheel speed sensor. Use a feeler gauge to measure the radial gap between the sensor tip and the magnetic encoder ring (standard: 0.3-1.2 mm). Check the encoder ring surface for scratches, corrosion, or foreign matter. After cleaning, check magnetic pole integrity (use iron filings to test magnetic distribution).
  • 4
    Use an oscilloscope to monitor the sensor signal waveform. Slowly rotate the wheel and verify a regular square or sine wave. Check for spikes, flat tops, or missing pulses. Compare the waveform with the left front wheel to confirm consistent amplitude and frequency.
  • 5
    If the above checks are normal, perform the IPB system calibration procedure (access IPB Special Functions → Wheel Speed Sensor Calibration via the diagnostic tool) and verify the IPB software is the latest version (compare against the TPI technical bulletin). If the fault is intermittent, inspect pin 26 (right front wheel speed signal) of IPB harness connector X1 for looseness or oxidation.
Real-World Cases
BYD DTC AI Analysis

Worn right front bearing on Song PLUS DM-i causing excessive clearance

✓
A 2021 Song PLUS DM-i with 60,000 km intermittently illuminated the ABS and ESC warning lights on the instrument panel. The scan tool retrieved DTC C050B76. Freeze frame data showed the fault occurred at 60 km/h when the right front wheel speed signal suddenly dropped to zero. Inspection found 0.8 mm of axial play in the right front hub bearing, causing the air gap between the magnetic encoder ring and sensor to vary dynamically while driving. Replaced the right front hub assembly (including the encoder ring) and adjusted the sensor air gap to 0.6 mm. Fault resolved.
BYD DTC AI Analysis

Sensor harness chafed at steering knuckle and shorted

✓
DTC C050B76 appeared after the vehicle drove through water, accompanied by restricted Automatic Emergency Braking function. Inspection found the right front wheel speed sensor wiring harness chafed where it passes through the steering knuckle bracket, with the copper core intermittently shorting to the body. The fault showed normal operation at low speeds but signal abnormalities during high-speed cornering when the harness stretched. Repaired the damaged wiring, reinforced the insulation with heat shrink tubing, and re-secured the harness routing to prevent contact with suspension components.
BYD DTC AI Analysis

Mismatched tyre specifications caused related faults

✓
The owner replaced the right front tyre; the warning light illuminated the next day showing DTC C050B76. Inspection revealed the new tyre was size 225/55R18, while the original and other three tyres were 225/60R18, causing the right front rolling circumference to differ from the other wheels by approximately 3%. The IPB system flagged the right front sensor signal as faulty based on four-wheel speed differential logic. Fitting the correct size tyre and performing tyre pressure calibration cleared the fault.
BYD DTC AI Analysis

Oxidized IPB control unit connector caused signal drift

✓
Southern humid region vehicle. After one week parked, C050B76 triggered immediately at startup. Sensor power supply normal, but signal line voltage fluctuated between 0.5–3V (normal: 0–12V pulse). Disconnected IPB control unit connector; pin 26 (right front wheel speed signal) showed green corrosion. Cleaned connector with electronic contact cleaner, applied conductive grease, and replaced terminals as needed. Fault resolved.
Other Atto 8 Fault Codes
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.B110A02DTC B110A02 indicates the thermal management master control unit (HVAC ECU) or body control module (BCM) failed to receive valid CAN data frames from the PM2.5 air quality sensor over consecutive communication cycles (typically 500ms per cycle). The sensor typically mounts at the HVAC unit air inlet or behind the glove box and transmits real-time particulate concentration data (unit: μg/m³) to the HVAC controller via the CAN bus. The fault is essentially a communication link layer timeout. Potential causes include physical layer wiring faults, sensor power supply failures, sensor internal MCU lockup, or CAN network topology damage. Although this non-critical fault does not directly affect driving safety, it disables the intelligent air purification strategy and the automatic fresh air/recirculation switching function. In extreme cases, it triggers a thermal management system degraded mode, limiting compressor power or fixing the air flap position.B110B07This fault code indicates abnormal operation of the internal air pump (sampling pump) in the PM2.5 air quality detection module. The PM2.5 detector uses the laser scattering principle to measure particulate concentration and requires a built-in air pump to draw ambient air into the detection chamber at a constant flow rate. The ECU sets this code when it detects an open or short in the air pump drive circuit, abnormal current (stall or free-running), or abnormal speed feedback. This fault causes the automatic air conditioning system to lose air quality sensing capability, preventing automatic switching between fresh air and recirculation modes. The instrument cluster air quality display may show '--' or a fixed value, but the fault does not affect the vehicle powertrain or basic air conditioning cooling and heating functions.B173CDTC B173C indicates the Supplemental Restraint System (SRS) detects the Right Second Row Side Airbag squib circuit resistance exceeds the calibrated threshold (typically >4.5Ω). This fault is an active diagnostic result of the SRS system, indicating a high-resistance condition in the circuit between the Airbag Control Unit (ACU) and the airbag module. Causes for excessive resistance include increased contact resistance, a partially broken wiring harness, terminal oxidation, or an aging squib wire inside the airbag module. This fault causes the system to mark the airbag circuit as 'unreliable', meaning the airbag may fail to deploy during a collision. The fault typically illuminates the instrument cluster airbag warning light (SRS light) continuously, and some models also sound a warning buzzer.
Common problems reported for Atto 8 →Atto 8 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.