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C051176

The BYD IPB (Intelligent Integrated Braking System) defines DTC C051176 as "Incorrect Installation Direction of Left Rear Wheel Speed Sensor" — Seal U

Braking System

The BYD IPB (Intelligent Integrated Braking System) defines DTC C051176 as "Incorrect Installation Direction of Left Rear Wheel Speed Sensor".

This fault does not indicate a simple open or short circuit.

Instead, the magnetic pole direction of the Hall-effect wheel speed sensor mismatches the relative position of the tone ring, reversing the output square-wave signal phase or generating an abnormal duty cycle.

The IPB control unit triggers this code upon detecting unexpected rising and falling edge timing in the signal waveform, or upon identifying a logical conflict between the left rear wheel speed signal and the other three wheels during vehicle speed calculation.

This fault directly disables or falsely triggers the Anti-lock Braking System (ABS), Electronic Stability Program (ESP), Automatic Emergency Braking (AEB), and tire pressure monitoring system (calculated via wheel speed differentials), severely compromising driving safety.

The C051176 fault code on the Seal U indicates the left rear wheel speed sensor is installed in the wrong direction or has an incorrect signal orientation. This medium-severity fault can affect ABS, ESP, AEB, and indirect tire pressure monitoring. Common causes include the sensor being rotated 180° during installation or a non-genuine sensor with reversed polarity. Visit an authorised BYD dealer for diagnosis and correction. Typical repair cost data is available.
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Cases Logged
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Causes
Likely Causes — Seal U
  • 1Sensor body rotated 180° during installation: The technician failed to align the locating marks when inserting the sensor into the mounting hole after replacing the bearing or brake system, reversing the Hall element magnetic pole direction relative to the tone ring.
  • 2Using a non-genuine aftermarket sensor: Some third-party parts have magnetic pole markings opposite to the genuine part, or an internal Hall chip orientation that mirrors the genuine part, resulting in correct physical installation but incorrect electrical direction.
  • 3Loose sensor mounting: Retaining bolt not tightened to specified torque (8-10 N·m) or stripped steering knuckle mounting hole threads allow driving vibration to gradually rotate and displace the sensor.
  • 4Abnormal sensor-to-tone ring air gap with directional deviation: When the air gap exceeds the 0.3-0.8 mm standard range, IPB signal phase tolerance decreases, and a slight directional deviation triggers the fault.
  • 5Wiring harness shield interference: An intermittent short circuit between the sensor signal wire (white) and the shield wire distorts the signal waveform, causing the control unit to falsely detect an incorrect installation direction.
What To Do
  • 1
    Connect the VDS2000/BYD dedicated diagnostic tool, read the IPB system fault codes to confirm the presence of C051176, and record the freeze frame data (especially vehicle speed and wheel speed values when the fault occurred).
  • 2
    Raise the vehicle to a suitable height and remove the left rear wheel. Visually inspect the wheel speed sensor condition, connector locking tab, and wiring harness routing. Confirm the arrow mark on the sensor head points toward the wheel center/tone ring.
  • 3
    Disconnect the sensor connector and measure the supply voltage (12V ± 0.5V), ground wire continuity, and signal wire resistance (1.2-2.0 kΩ at 20°C) to rule out basic circuit faults.
  • 4
    Remove the sensor. Clean the mounting hole and sensor tip. Check the tone ring for missing teeth, deformation, or oil contamination. Use a feeler gauge to measure the clearance between the sensor tip and the top of the tone ring teeth. Verify the clearance is 0.3-0.8 mm.
  • 5
    Reinstall the sensor according to the repair manual: align the sensor locating boss with the alignment slot in the steering knuckle mounting hole, and point the sensor arrow mark toward the inboard side of the wheel (magnetic pole facing the tone ring). Tighten the bolt to the specified torque of 8-10 N·m.
  • 6
    Connect the diagnostic tool and perform "Wheel Speed Sensor Position Learning" or "ABS Static Calibration" (some models require this step), then clear the fault codes.
  • 7
    Perform a road test: Read the data stream at multiple vehicle speeds (e.g., 10 km/h, 40 km/h, and 80 km/h). Confirm the left rear wheel speed signal synchronizes with the other three wheels and shows no signal jumps; verify the ABS self-check and ESP functions operate normally.
Real-World Cases
BYD DTC AI Analysis

Installed ABS sensor backwards after wheel bearing replacement on Qin Pro, causing ABS warning light to come on

✓
At intake, the ABS and ESP warning lights stayed on constantly and the speedometer needle fluctuated at 40-60 km/h. The scan tool read codes C051176 and C003700. On the lift, the left rear wheel speed sensor showed signs of previous removal; the magnetic head direction mark was off by approximately 180 degrees. Further inspection found metal debris in the mounting hole. Cleaned the hole and reinstalled the sensor with the mark facing inward toward the wheel, setting the air gap to 0.5 mm. Cleared the faults and road-tested 10 km. Live data read normal and the warning lights went out.
Original source ↗
BYD DTC AI Analysis

Song Pro DM wiring harness chafing coupled with incorrect sensor orientation

✓
Dashboard displayed "Please check ESP system" and the reversing camera intermittently blacked out. DTCs C051176 and C050E00 set. Found the wiring harness crushed and damaged at the rear wheel arch liner, with the signal wire intermittently contacting the shield wire. Also found the sensor installed at the wrong angle; incorrect connector orientation misaligned the Hall element with the tone ring. Repaired the insulation and adjusted the routing. Reinstalled the sensor, ensuring the locating boss clipped into the mounting hole. Applied conductive paste and performed sensor calibration. Fault resolved.
Original source ↗
BYD DTC AI Analysis

Loose sensor mounting bolts on a new Seal caused dual abnormalities in air gap and orientation.

✓
At 2000 km the new vehicle set tyre pressure and ESP faults; actual pressures were normal. Retrieved DTCs C051176 and C051000 (air gap abnormal). Inspection revealed loose mounting bolts. The sensor had shifted outward and rotated within its bore, causing magnetic pole misalignment. Air gap measured 1.2 mm, exceeding specification. Installed a new sensor (BYD-3630100), aligned it precisely with the anti-rotation feature, and torqued the bolts to 8 N·m. Performed ABS system calibration; fault cleared.
Original source ↗
BYD DTC AI Analysis

Aftermarket sensors fitted to the Han EV caused signal phase reversal.

✓
Frequent false ESP triggering on wet roads caused the dashboard to display a "Service ESP" warning. Data stream showed abnormal left rear wheel speed fluctuation below 10 km/h. Inspection revealed an aftermarket wheel speed sensor had been previously installed. Although the physical mounting direction appeared correct, oscilloscope testing showed the output waveform phase was reversed from OEM specification. Replaced the sensor with an OEM unit, cleaned oil from the tone ring, and performed static and dynamic calibration after proper installation. Waveform tests read normal and the fault has not returned.
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.