AU
C051776

The IPB (Intelligent Integrated Braking System) or ESC (Electronic Stability Control System) triggers this DTC — Atto 8

Braking System

The IPB (Intelligent Integrated Braking System) or ESC (Electronic Stability Control System) triggers this DTC.

It indicates a wrong installation direction for the right rear wheel speed sensor.

The sensor uses the Hall effect principle; its internal magnetic poles have a specific bias direction to identify the tone ring rotational direction.

Installing the sensor opposite to the calibrated direction, or swapping the left and right sensors, produces an output signal polarity opposite to ECU expectations.

This prevents the system from correctly interpreting the wheel speed signal.

This condition degrades or disables functions such as ABS, ESP, Auto Hold, and Automatic Emergency Braking, representing a brake safety-related functional fault.

The C051776 fault code on the Atto 8 indicates the right rear wheel speed sensor is installed in the wrong direction or has the wrong signal polarity. Severity is medium because it can affect ABS, ESP, Auto Hold, and Automatic Emergency Braking. Common causes include swapped left and right rear sensors, backward installation, or a non-genuine mismatched part. Visit an authorised dealer for inspection and correct sensor installation. Typical repair cost data is available.
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Cases Logged
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Causes
Likely Causes — Atto 8
  • 1Mistakenly swapping the left and right rear wheel speed sensors during repair work, or installing the sensor backwards by failing to observe the arrow mark on the sensor housing.
  • 2Installing a non-genuine part or a wheel hub bearing unit from a different batch causes a mismatch between the sensor magnetic pole orientation and the tone ring.
  • 3During accident repairs, the technician failed to install the sensor in the orientation specified by the workshop manual, or used a refurbished part.
  • 4Selecting a matching sensor with the incorrect orientation when replacing the integrated wheel hub bearing unit (on some models, the bearing and sensor are integrated).
  • 5Loose sensor retaining bolt or deformed mounting bracket causing the sensor to rotate out of position while driving (less common).
What To Do
  • 1
    Use VDS or a dedicated diagnostic tool to read the fault code, confirm C051776 is active, and check the right rear wheel speed data stream for abnormalities (e.g., missing signal, erratic signal, or mismatch with actual vehicle speed).
  • 2
    Raise the vehicle and inspect the right rear wheel speed sensor harness connector for looseness, water ingress, or corrosion. Measure the sensor supply voltage (usually 12V or 5V, depending on the vehicle model).
  • 3
    Visually inspect the sensor installation direction. Verify the arrow mark on the sensor housing points toward the front of the vehicle (mirrored relative to the left rear wheel). Verify the mounting bolt torque meets the standard (typically 8-12 N·m).
  • 4
    Remove the sensor and compare the left and right wheel sensor part numbers to verify they are not swapped. Check the sensor tip for metal shavings or physical damage.
  • 5
    If the sensor is integrated into the wheel hub bearing unit, verify the bearing assembly part number matches the VIN. If necessary, replace the right rear wheel hub bearing unit as a complete assembly.
  • 6
    When reinstalling, strictly align the direction marks and verify the air gap between the sensor and the tone ring meets the standard (usually 0.5-1.5 mm).
  • 7
    Use the diagnostic tool to perform the 'Wheel Speed Sensor Direction Learning' or 'Sensor Calibration' procedure (required for some e-Platform 3.0 models), then clear the fault code.
  • 8
    Perform a road test: drive straight at low speed and observe four-wheel speed data stream synchronization, perform an emergency braking test to confirm ABS function recovery, and verify the ESP fault light turns off.
Real-World Cases
BYD DTC AI Analysis

BYD Yuan Plus sets C051776 after wheel speed sensor replacement

✓
The owner reported that while driving normally, the ABS and ESP warning lights suddenly illuminated on the dashboard with a 'Check ESP System' message. The vehicle jerked when pulling away, and the auto hold function failed. The technician used a diagnostic scanner and retrieved fault code C051776 (Right Rear Wheel Speed Sensor Incorrect Installation Direction). The technician first checked the right rear wheel speed sensor connector and found no looseness or water ingress. The owner stated that a non-dealership workshop had replaced the right rear wheel speed sensor one week prior. The technician removed the right rear wheel for inspection and found that although the replacement wheel speed sensor matched the original part number, the arrow marking on the sensor housing pointed opposite to the left rear wheel. According to the workshop manual, this sensor is directional and requires correct installation orientation to identify the tone ring rotation direction. Solution: Reinstalled the right rear wheel speed sensor with the direction arrow on the sensor housing pointing toward the front of the vehicle (mirror image of the left rear sensor). After clearing the fault codes and road testing, the ABS and ESP warning lights turned off, live data showed normal right rear wheel speed signals, and the auto hold function returned to normal.
Original source ↗
BYD DTC AI Analysis

New Seal 06 DM-i inspection found C051776

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A new vehicle with only 2000 km. At the first service, the owner reported the ESP warning light occasionally flickered but extinguished automatically. The dealership technician connected a VDS scan tool and found stored fault codes C051776 (Right rear wheel speed sensor installation direction error) and C051600 (Right rear wheel speed sensor abnormal air gap). The technician raised the vehicle and inspected the right rear wheel. The wheel speed sensor retaining bolt torque was normal, but the sensor and bearing unit were not original matching parts. Further inspection revealed the sensor was a used part removed from a different batch of vehicles. Although the part number matched, different manufacturing batches resulted in opposite internal magnetic polarity. Because the Seal 06 uses an integrated bearing unit, the wheel speed sensor and bearing are matched components; an incorrect batch or sensor direction causes signal phase errors. Solution: Replaced the right rear wheel bearing unit (including wheel speed sensor) with a brand new part matched to the VIN. During installation, ensure the sensor connector faces the correct direction and tighten the bolt to standard torque (typically 8–12 N·m) using a torque wrench. Perform sensor calibration and road testing. The fault codes did not reappear.
Original source ↗
BYD DTC AI Analysis

BYD Song Plus DM-i sets C051776 after accident repair

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Vehicle sustained a collision on the right rear side. A general repair shop carried out repairs to the rear axle and right rear wheel area. After delivery, the owner noticed abnormal ESP intervention during straight-line driving and unstable speedometer readings at high speeds. Fault code C051776 stored and would not clear. The technician compared right and left rear wheel speed sensor live data, finding significant discrepancies at low speeds, with abnormal spikes in the waveform. Disassembly revealed that although the repair shop had installed a genuine right rear wheel bearing, they failed to observe the wheel speed sensor orientation. Further inspection showed this model uses Hall effect wheel speed sensors that are direction-sensitive; reverse installation reverses signal polarity. Solution: Remove the right rear brake disc and bearing unit and reposition the wheel speed sensor in the correct orientation. Due to the high integration of the bearing unit and sensor on this model, some workshops replace the complete right rear hub bearing assembly. After replacement, run the "Wheel Speed Sensor Direction Learning" procedure with a diagnostic scanner, clear fault codes, and conduct straight-line and cornering road tests to confirm synchronous signals from all four wheels.
Original source ↗
BYD DTC AI Analysis

Destroyer 05: fault codes after wheel speed sensor swap

✓
While diagnosing another fault, the technician mistakenly swapped the left and right rear wheel speed sensors. Immediately after installation, the instrument cluster displayed an ESP fault. The scanner showed codes C051776 (right rear) and C051176 (left rear, indicating incorrect left rear sensor orientation). The technician realized he had installed them on the wrong sides. Comparing the two sensors revealed that although they looked identical, the magnetic pole bias direction at the sensor heads was opposite—designed to match the rotation direction of the left and right wheel bearing tone rings. With the sensors swapped, the detected signal phase was opposite to what the ECU expected, triggering the orientation error. Solution: Swap the left and right rear wheel speed sensors back to their correct sides. Clear the fault codes and check the four-wheel speed data to confirm all signals change synchronously with vehicle speed without abnormal jumps or delays. This case shows that wheel speed sensors on some newer BYD models have strict left/right distinctions and cannot be interchanged.
Original source ↗
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.