AU
C050800

DTC C050800 indicates an abnormal short circuit between the right front wheel speed sensor power supply circuit (typically a 12V or 5V reference voltage) and body ground (GND) — Seal U

Braking System

DTC C050800 indicates an abnormal short circuit between the right front wheel speed sensor power supply circuit (typically a 12V or 5V reference voltage) and body ground (GND).

In the BYD IPB (Integrated Power Brake) architecture, the active wheel speed sensors (Hall-effect or magnetoelectric) require a stable operating voltage from the ECU.

When the power supply line shorts to ground, the IPB module detects an abnormal current increase or a voltage drop to near 0V and triggers the fault protection mechanism.

This fault causes the loss of the right front wheel speed signal, disabling or degrading functions such as the Anti-lock Braking System (ABS), Electronic Stability Control (ESC), Traction Control System (TCS), and Automatic Emergency Braking (AEB).

This hard fault severely impacts driving safety.

The C050800 fault code on the Seal U indicates a short circuit between the right front wheel speed sensor power supply and ground. This is a high-severity fault that can disable or reduce ABS, ESC, TCS, and AEB functions. Common causes include damaged sensor wiring insulation or an internal short in the sensor. The recommended fix is to visit an authorised dealer for diagnosis and repair. Typical repair cost data is available.
5
Cases Logged
5
Causes
Likely Causes — Seal U
  • 1Damaged right front wheel speed sensor wiring harness insulation: Long-term friction and vibration at the steering knuckle, suspension control arm, or body pass-through hole wears through the outer sheath, causing the internal power wire to contact the metal body and create a short to ground.
  • 2Internal short circuit in sensor body: Hall element or internal circuit board fault shorts the power supply pin to the housing, commonly caused by sensor aging, overheating, or water ingress corrosion.
  • 3Connector water ingress or corrosion: A poorly sealed right front wheel speed sensor connector (located in the fender liner or engine compartment) allows water to accumulate inside after washing the vehicle or driving through water, causing a short circuit between the power terminal and the ground terminal.
  • 4IPB control unit internal drive circuit fault: The voltage regulation circuit or MOSFET inside the IPB module supplying power to the wheel speed sensors breaks down, causing a short circuit to ground at the output terminal. Multiple wheel speed sensors may simultaneously report power supply short circuit faults.
  • 5Modification or accident repair damage: Retaining clips crush the wiring harness, screws pierce the harness, or incorrect routing causes contact with sharp edges during mud flap installation, brake system modification, or accident repairs.
What To Do
  • 1
    Safety check and preliminary diagnosis: Connect the VDS diagnostic tool and confirm the fault code status is current (Active). Read the right front wheel speed sensor data stream and confirm no signal output. Inspect the IPB power supply fuse; a blown fuse indicates a severe short circuit. Disconnect the IPB and right front wheel speed sensor connectors. Measure the resistance from the sensor-side power supply pin to ground. A reading below 1Ω confirms a short to ground.
  • 2
    Wiring harness visual inspection: Raise the vehicle, remove the right front wheel and fender liner. Inspect the wiring harness sheath along the entire wheel speed sensor harness routing (from wheel hub bearing → steering knuckle → fender liner → engine compartment) for abrasion, cuts, or burn marks. Carefully inspect interference points between the harness and the steering knuckle, brake hose, and suspension spring, and check the rubber grommet at the body pass-through for aging or detachment.
  • 3
    Sectional isolation measurement: Disconnect the wiring harness at the sensor connector. Measure the resistance between the sensor body power terminal and the housing (normal: infinite; if continuity exists, replace the sensor). Measure the resistance to ground of the harness-side power wire. If a short circuit exists on the harness side, use the bisection method: strip the harness at the routing midpoint for inspection to gradually narrow the fault scope to the exact damage point.
  • 4
    In-depth connector inspection: Inspect the sensor connector terminals for backout, deformation, or green corrosion. Measure the insulation resistance between the female connector power pin and the adjacent ground pin. The resistance must exceed 10MΩ. If water ingress is present, dry the connector with compressed air and clean it with electronic contact cleaner. Replace the connector assembly and improve sealing if necessary.
  • 5
    IPB module verification: If the wiring harness and sensor are normal, measure the resistance to ground of the power supply output terminal at the IPB harness end. If continuity exists, disconnect the IPB connector and measure the resistance to ground of the corresponding pin inside the module. After confirming an internal IPB short circuit, replace the IPB assembly (perform bleeding and calibration procedures).
  • 6
    Repair and Verification: Repair the wiring harness (solder + heat shrink tubing + corrugated conduit protection) or replace the sensor/IPB. Restore all connections and clear the fault code. Perform a key cycle test to confirm the fault code does not return. Road test the vehicle (accelerate and decelerate between 10-40 km/h) to confirm the right front wheel speed signal synchronizes with the other wheel speeds and the ABS self-check is normal.
Real-World Cases
BYD DTC AI Analysis

Song PLUS DM-i right front wheel speed sensor wiring harness chafed through at steering knuckle and shorted

✓
After driving through water, the ABS light illuminated with DTC C050800. Inspection revealed the right front wheel speed sensor harness had chafed where it passes through the steering knuckle retaining clip. Prolonged steering movement wore through the insulation, exposing copper wires that contacted the steering knuckle metal and shorted to ground. Repaired the damaged harness (3 wires, including the power wire shorted to ground), rewrapped and rerouted the wiring, and fitted a rubber grommet to prevent contact with sharp edges. Replaced the damaged waterproof connector. Fault resolved.
BYD DTC AI Analysis

Internal driver circuit failure in the IPB module caused a short circuit in the power supply to multiple wheel speed sensors.

✓
Post-accident repair. DTC C050800 set after right-front impact. Harness visually intact; sensor readings normal. Disconnected IPB connector and measured 0.2Ω to ground on the supply pin at the harness side. Replaced right-front wheel speed sensor; fault persisted. Found the LDO regulator supplying the right-front sensor shorted inside the IPB. Replaced IPB assembly, bled IPB and calibrated sensors; fault resolved.
BYD DTC AI Analysis

Internal short circuit in the sensor body caused intermittent DTC C050800

✓
Owner reported intermittent ABS warning light on, particularly frequent during wet weather. Scanner showed DTC C050800 as an intermittent fault. Harness insulation tested good, but wiggling the sensor harness reproduced the fault. Removed the sensor and measured resistance between the internal power terminal and housing: erratic, fluctuating between infinite and continuity. Internal Hall element encapsulation seal failed, causing internal short in humid conditions. Replaced right front wheel speed sensor. Fault eliminated.
BYD DTC AI Analysis

Modified brake lines pinched wiring harness, causing short circuit

✓
One week after fitting a high-performance braking system, DTC C050800 appeared. Inspection found the modified braided brake line mounting bracket incorrectly positioned, pinching the original wheel speed sensor harness and shorting the power wire to the shield/ground inside the loom. Rerouted the harness, adjusted the brake line mounting points, and repaired the damaged wiring (insulation breached at 3 points). Fault cleared. Retain the original wiring harness clip positions when modifying.
BYD DTC AI Analysis

Connector terminal backed out, causing power pin to contact metal bracket

✓
The ABS warning light suddenly came on after driving over rough road. Inspection found the right front wheel speed sensor connector wasn't fully locked. The internal power terminal (female) had backed out and contacted the metal retaining clip of the connector housing, shorting to ground through the body. Cleaned the connector internals, repaired the terminal retention structure, and ensured the connector clicked fully into place (heard the 'click'). Applied conductive grease to prevent oxidation. 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.