AU
C051400

This DTC indicates the IPB (Intelligent Integrated Braking System) detects an abnormally low-resistance connection between the right rear wheel speed sensor power supply circuit (typically a 12V or 5V reference voltage) and body ground (GND), constituting a short to ground — Seal U

Braking System

This DTC indicates the IPB (Intelligent Integrated Braking System) detects an abnormally low-resistance connection between the right rear wheel speed sensor power supply circuit (typically a 12V or 5V reference voltage) and body ground (GND), constituting a short to ground.

In the BYD IPB system, the wheel speed sensor is a two-wire active Hall sensor.

The ECU supplies operating voltage to the sensor via the power supply line.

A short to ground on the power supply line causes: 1) complete loss of the right rear wheel speed signal; 2) the IPB system to trigger limp mode, automatically disabling the dynamic functions of the ABS, ESC, Automatic Emergency Braking (AEB), and Electronic Parking Brake (EPB); 3) potential damage to the internal IPB driver circuit if the short-circuit current is excessive.

This is a hard-wire circuit fault, not signal interference or performance degradation.

Repair the fault immediately to prevent braking system failure.

The C051400 fault code on the Seal U indicates a high-severity short to ground in the right rear wheel speed sensor power supply circuit. This can cause loss of the wheel speed signal and disable ABS, ESC, AEB, and EPB functions. Common causes include damaged sensor wiring insulation or an internal short in the sensor. Stop driving if braking warnings appear and 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 — Seal U
  • 1Damaged right rear wheel speed sensor harness insulation: Stones striking the underbody during driving split the harness sheath, or loose harness retaining clips cause long-term friction against suspension components, exposing the power wire copper core and allowing it to contact the vehicle body.
  • 2Wheel speed sensor internal short circuit: Breakdown of the internal Hall element or capacitor shorts the power supply terminal to the sensor housing (ground). Common causes include sensor aging, overheating, or manufacturing defects.
  • 3Wiring harness connector water ingress and corrosion: Wading or direct high-pressure washing in the right rear wheel area causes sensor plug seal failure. This forms an electrolyte conductive path between the pins, short-circuiting the power supply pin to the ground pin.
  • 4Internal drive circuit fault in the IPB control module: The constant current source or voltage regulator chip inside the IPB module supplying power to the wheel speed sensors breaks down, causing the output terminal to short to ground. This fault typically triggers simultaneous power supply short-circuit fault codes across multiple wheel speed sensors.
  • 5Harness damage from accident or modification: The vehicle sustained a right-rear collision, and improper routing during repair pinched the harness; or fixing screws pierced the harness during the installation of aftermarket components such as reverse sensors or mud flaps.
What To Do
  • 1
    Safety preparation and fault confirmation: Use VDS or a dedicated diagnostic tool to read the complete fault codes; confirm only C051400 is present or accompanied by related wheel speed signal faults; inspect the right rear wheel speed sensor connector for looseness, backed-out pins, or corrosion; verify the vehicle is stationary when the fault occurs (to rule out electromagnetic interference while driving).
  • 2
    Sensor body inspection: Disconnect the right rear wheel speed sensor connector. Use a multimeter to measure the resistance between the sensor-side power supply pin and the ground pin (or sensor metal housing). Normal resistance must exceed 10 MΩ (open circuit). If the resistance is less than 1 Ω, replace the right rear wheel speed sensor. Also measure the resistance between the sensor signal pin and the power supply pin. Normal resistance is 1-2 kΩ (Hall sensor internal resistance).
  • 3
    Harness continuity and insulation test: Keep the sensor connector disconnected. From the IPB module side (located in the engine compartment or cabin front bulkhead), locate the right rear wheel speed sensor power supply pin and measure its resistance to ground. Normal resistance is greater than 10 MΩ. A reading of 0-5 Ω confirms a short to ground. Use a multimeter in buzzer mode to check harness continuity section by section. Focus on areas where the harness passes through body sheet metal holes and bends near the suspension spring seat.
  • 4
    Short circuit location and repair: If confirming a wiring harness short circuit, progressively strip back the harness protective sleeve from the IPB module towards the wheel. Focus inspection on the firewall wiring grommet and the rear wheel arch liner area. Upon locating the damage, if minor (single wire damaged), apply a double layer of waterproof heat-shrink tubing. If multiple wires are damaged or the copper cores are severely oxidized, replace the right rear wheel speed sensor wiring harness assembly (part number usually starts with CJ). Check and replace any damaged harness retaining clips. Maintain a minimum clearance of 20mm from moving parts.
  • 5
    IPB Module Verification and Testing: If the wiring harness and sensor are normal, measure the output voltage at the corresponding IPB module pin (ignition switch ON, do not disconnect the connector). Normal voltage is battery voltage (12V) or 5V reference voltage. If the module output terminal is shorted to ground, replace the IPB assembly (perform coding and longitudinal acceleration sensor calibration). After repair, clear the fault codes and perform a road test (vehicle speed above 40 km/h). Confirm normal wheel speed data stream and no fault code recurrence. Verify ABS and ESC functions operate normally.
Real-World Cases
BYD DTC AI Analysis

Song PLUS DM-i right rear wheel speed sensor wiring harness chafed and shorted

✓
Dashboard displayed "Check ABS System" and "Automatic Emergency Braking Limited". VDS retrieved DTC C051400. Lifted the vehicle and found the RH rear wheel speed sensor harness chafed where it passes through the subframe. The internal power supply wire (red/black) had exposed copper contacting the subframe, causing a short to ground. Repair: Cut out the damaged section, crimped new waterproof terminals, sealed with double-layer heat shrink tubing, rerouted the harness and added corrugated tubing protection. Fault resolved.
BYD DTC AI Analysis

Right rear wheel speed sensor connector corroded and shorted after driving through water

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Owner reported multiple dashboard warning lights after driving through heavy rain and floodwater. Diagnosis revealed DTCs C051400 and C051100 (similar fault for the right front wheel). Inspection found water inside the right rear wheel speed sensor connector; a conductive film between the power and ground pins measured only 0.3Ω. Disassembled the connector, cleaned it with anhydrous ethanol, dried it with an air gun, applied conductive grease, and replaced the waterproof seal. Cleared the fault codes; they did not return.
BYD DTC AI Analysis

Damage to the IPB internal driver chip shorted the power supply to multiple wheel speed sensors.

✓
Accident-repaired vehicle (right rear previously impacted). Replaced right rear wheel speed sensor and wiring harness; C051400 persisted. Further inspection found the MOSFET inside the IPB module that supplies power to the right rear wheel had shorted internally, with the output shorted to ground. Voltage at the right rear wheel speed sensor connector measured 0V (nominal 12V), and the corresponding pin at the IPB module connector also showed a short to ground. Solution: Replaced the IPB intelligent integrated brake system assembly and performed online configuration and sensor calibration.
BYD DTC AI Analysis

改装挡泥板固定螺丝刺穿线束

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用户自行加装后轮挡泥板后一周内出现故障。检查发现右后轮罩内衬新加装的自攻螺丝过长，直接穿透线束导致供电线与车身搭铁短路。修复措施：拆除螺丝，更换受损线束段，重新布设线束避开改装件安装位，使用原车预留的线束固定卡扣，教育用户避免在非标准位置打孔。
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.