AU
C051776

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

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 Seal U indicates the right rear wheel speed sensor is installed in the wrong direction or has incorrect signal polarity. This is a medium-severity brake safety fault that can affect ABS, ESP, Auto Hold, and Automatic Emergency Braking. Common causes include swapped rear sensors, reverse installation, or a mismatched hub bearing. Visit an authorised dealer for inspection and correct refitting or replacement. Typical repair cost data is available.
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Cases Logged
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Causes
Likely Causes — Seal U
  • 1Mistakenly swapping the left and right rear wheel speed sensors during repair work, or installing the sensor in reverse by failing to notice the arrow marking on the sensor housing.
  • 2Replacing the wheel hub bearing unit with a non-genuine part or one from a different batch causes the sensor magnetic pole direction to mismatch the tone ring.
  • 3During accident repairs, the technician failed to install the sensor in the direction specified by the workshop manual, or used a refurbished part.
  • 4Selected 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 codes, 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. Check the right rear wheel speed sensor wiring harness connector for looseness, water ingress, or corrosion. Measure the sensor supply voltage (typically 12V or 5V, depending on vehicle model).
  • 3
    Visually inspect the sensor installation direction. Confirm the arrow mark on the sensor housing points toward the front of the vehicle (mirror-symmetrical to the left rear wheel). Verify the fixing bolt torque meets the standard (usually 8-12 N·m).
  • 4
    Remove the sensor. Compare the left and right wheel sensor part numbers to verify correct installation sides. Check the sensor tip for metal debris contamination or physical damage.
  • 5
    If the sensor is integrated into the wheel hub bearing unit, verify the bearing assembly part number matches the VIN. Replace the right rear wheel hub bearing unit as a complete assembly if necessary.
  • 6
    When reinstalling, strictly align the direction marks and ensure 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 on some e-Platform 3.0 models), then clear the fault code.
  • 8
    Perform a road test for verification: drive straight at low speed and observe the four-wheel speed data stream synchronization, perform an emergency braking test to confirm ABS function recovery, and verify the ESP warning light is off.
Real-World Cases
BYD DTC AI Analysis

BYD Yuan Plus sets C051776 after wheel speed sensor replacement

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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

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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 Seal U Fault Codes
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.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.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.B173712DTC B173712 indicates a short to power in the firing circuit of the right second-row side airbag module in the Supplemental Restraint System (SRS). Specifically, the "right second-row side airbag" typically refers to the side impact airbag located in the right B-pillar or the side of the right seat. The "12" suffix indicates a circuit short to battery positive (B+). This fault causes the following conditions: 1) The airbag may fail to ignite and deploy during a collision, resulting in a loss of side impact protection. 2) In extreme cases, unintended triggering may cause accidental airbag deployment. 3) The SRS control unit detects abnormally high circuit voltage (typically above 4.5V) and enters fault protection mode. This may disable the entire airbag system and continuously illuminate the instrument cluster airbag warning light.
Common problems reported for Seal U →Seal U 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.