AU
C050C00

DTC C050C00 indicates the IPB (Integrated Intelligent Brake Control System) detects an electrical fault in the left rear wheel speed sensor (WSS) wiring harness, including an open circuit, short circuit, or short to ground or power — Seal U

Braking System

DTC C050C00 indicates the IPB (Integrated Intelligent Brake Control System) detects an electrical fault in the left rear wheel speed sensor (WSS) wiring harness, including an open circuit, short circuit, or short to ground or power.

This sensor, typically a Hall-effect or magnetoelectric type, converts wheel speed into an electrical signal and transmits it to the IPB module.

The IPB module uses this signal for precise control of systems including ABS, ESC, TCS, EPB, and Automatic Emergency Braking (AEB).

A wiring harness fault prevents the IPB from obtaining left rear wheel speed data and triggers a system degraded mode (ABS/ESC functions limited or disabled).

In extreme cases, this fault can affect brake force distribution, cause abnormal parking brake operation, or trigger speed-limiting protection, posing a driving safety risk.

The C050C00 fault code on the Seal U indicates a medium-severity electrical fault in the left rear wheel speed sensor wiring harness. This can stop the IPB brake control module from receiving wheel speed data, limiting ABS, ESC, TCS, EPB, or AEB functions. Common causes include a loose or corroded connector, water ingress, or a worn or broken harness near suspension parts. Visit an authorised dealer for diagnosis and repair. Typical repair cost data is available.
5
Cases Logged
5
Causes
Likely Causes — Seal U
  • 1Loose connection, backed-out pins, water ingress, or oxidation/corrosion at the left rear wheel speed sensor wiring harness connector, causing increased contact resistance.
  • 2Wiring harness worn, chafed, or completely broken at suspension movement points (such as near the steering knuckle, control arm, or shock absorber) due to a detached retaining clip.
  • 3Sensor body internal coil burnt out, Hall element failed, or probe damaged.
  • 4Wheel hub bearing magnetic encoder ring (magnetic ring) is damaged, detached, or contaminated with excessive iron debris, causing an abnormal signal that the system misdiagnoses as a wiring harness fault.
  • 5IPB control module internal left rear wheel speed signal input interface circuit fault (such as a burned sampling resistor or shorted filter capacitor).
What To Do
  • 1
    Use the VDS2000/VDS3000 diagnostic tool to read the fault codes and freeze frame data. Confirm the vehicle speed, road conditions, and associated fault codes at the time of the fault. Check if the left rear wheel speed data stream reads 0 or fluctuates abnormally.
  • 2
    Raise the vehicle to a suitable height and visually inspect the entire left rear wheel speed sensor wiring harness. Check the protective sleeve for damage, chafing, or water ingress, especially where it passes through body holes and near the suspension control arm and shock absorber.
  • 3
    Disconnect the left rear wheel speed sensor connector and IPB module connector. Use a multimeter to measure harness continuity (pin-to-pin resistance <1Ω), and check for short to ground (resistance to body >10MΩ) and short to power (resistance to +B >10MΩ).
  • 4
    Check the connector terminals for green oxidation, enlarged or deformed pin sockets, or backed-out pins. Clean with electrical contact cleaner. Replace the connector or repair the terminals if necessary.
  • 5
    Connect the sensor connector, turn the ignition to ON, and measure the sensor supply voltage (should be 5V±0.25V) and the signal wire reference voltage (usually around 2.5V). Manually turn the wheel and observe if the signal voltage produces pulse changes (alternating between 0.5V and 4.5V).
  • 6
    If the wiring harness and power supply are normal, replace the left rear wheel speed sensor. Observe the installation gap (usually 0.3-1.2mm, depending on vehicle model) and fastening torque (usually 8-12N·m) to prevent an excessive gap from causing signal loss.
  • 7
    Clear the fault code, perform sensor calibration (if required), and conduct a road test to verify: drive at 20-40 km/h or higher, observe the diagnostic tool data stream to verify the left rear wheel speed matches the other wheel speeds, and confirm the instrument warning light turns off and system function returns to normal.
Real-World Cases
BYD DTC AI Analysis

Song PLUS DM-i – Left rear wheel speed sensor wiring harness oxidised, causing intermittent fault

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The instrument cluster intermittently illuminated ABS and ESC warning lights with DTC C050C00 logged. Inspection of the left rear wheel speed sensor harness revealed water ingress and oxidation in the body-to-chassis harness connector (located near the left rear sill), causing increased signal resistance and abnormal voltage drop. The technician cleaned the connector terminals, sprayed electronics cleaner, applied conductive grease, and reconnected the harness with waterproofing. Fault resolved.
Original source ↗
BYD DTC AI Analysis

Qin Pro EV left rear wheel speed sensor harness worn through, open circuit

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Driving on rough roads, the dashboard suddenly displayed "Please Check Brake System" with DTC C050C00. Lifted the vehicle and found the wiring harness retaining clip at the left rear suspension had detached. The harness had been rubbing against the lower control arm, wearing through the insulation and breaking the internal copper wires. Repaired and re-wrapped the harness, secured it along standard routing with >50mm clearance from moving parts. Cleared the DTC; road test normal.
Original source ↗
BYD DTC AI Analysis

Han EV left rear wheel speed sensor damage misdiagnosed as wiring harness fault

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C050C00 set immediately on startup after overnight parking and would not clear. Initial checks confirmed normal wiring harness continuity and 5V supply, but sensor resistance measured infinite (normal: 1.2–1.8kΩ). Replaced the left rear wheel speed sensor, cleared the fault code with a diagnostic tool, and performed wheel speed sensor signal calibration (requires driving more than one complete revolution for the IPB to learn the tone ring error). Fault resolved. The original sensor had an internal coil open circuit, causing the IPB to misdiagnose this as a wiring open circuit fault.
Original source ↗
BYD DTC AI Analysis

BYD Song PLUS DM-i IPB module internal interface fault

✓
Replaced the left rear wheel speed sensor and complete wiring harness, but DTC C050C00 persisted. Data stream showed left rear wheel speed constantly at zero. Pin measurements at the IPB module revealed an internal open circuit between the left rear wheel speed signal input pin and the sampling circuit (internal module fault). Replaced the IPB integrated brake control module assembly and strictly performed brake system bleeding, ESC calibration, and longitudinal acceleration sensor calibration. Fault completely resolved.
BYD DTC AI Analysis

Tang DM wheel hub bearing magnetic encoder ring damage causing associated faults

✓
DTC C050C00 accompanied by left rear wheel noise while driving. Disassembly revealed the wheel hub bearing magnetic encoder ring (magnetic ring) had rusted and flaked from prolonged water exposure, preventing the sensor from reading the correct speed signal. After multiple failed communication attempts, the IPB misdiagnosed this as a wiring harness open circuit. Replaced the left rear wheel hub bearing unit, thoroughly cleaned residual iron filings from the sensor probe, and set the correct clearance between the sensor and tone ring during installation. Fault resolved.
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.