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) — Atto 8

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.

5
Cases Logged
5
Causes
Likely Causes — Atto 8
  • 1Right front wheel speed sensor harness insulation damage: Long-term friction and vibration at the steering knuckle, suspension control arm, or body pass-through wears through the harness outer sheath. The internal power wire contacts the metal body, creating a short to ground.
  • 2Internal short circuit in the sensor body: A failed Hall element or internal circuit board shorts the power supply pin to the housing. Common causes include sensor aging, overheating, or water ingress corrosion.
  • 3Connector water ingress or corrosion: Poor sealing of the 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 has broken down, causing a short to ground at the output terminal. Multiple wheel speed sensors may simultaneously report power supply short circuit faults.
  • 5Modification or accident repair damage: During mud flap installation, brake system modification, or accident repairs, retaining clips pinch the wiring harness, screws pierce it, or incorrect routing causes contact with sharp edges.
What To Do
  • 1
    Safety check and pre-diagnosis: Connect the VDS diagnostic tool and confirm the DTC status is Active. Read the right front wheel speed sensor data stream to confirm no signal output. Check if the IPB power supply fuse is blown (a blown fuse indicates a severe short circuit). Disconnect the IPB and right front wheel speed sensor connectors. Measure the resistance to ground at the sensor-side power supply pin. A reading of less than 1Ω confirms a short to ground.
  • 2
    Wiring harness visual inspection: Raise the vehicle, remove the right front wheel and inner fender liner, and inspect the wiring harness sheath along the entire wheel speed sensor harness routing (from wheel hub bearing → steering knuckle → fender liner → engine compartment) for wear, cuts, or burn marks. Focus on interference points between the harness and the steering knuckle, brake hose, and suspension spring, and check the body pass-through rubber grommet for aging or detachment.
  • 3
    Sectional isolation measurement: Disconnect the wiring harness at the sensor connector. Measure the resistance between the sensor power terminal and the housing (normally infinite; if continuity exists, replace the sensor), and the resistance to ground of the harness-side power wire. If a short circuit exists on the harness side, use the bisection method: open the harness at the midpoint of the routing for inspection, gradually narrowing the fault scope to the exact damaged 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. Normal resistance is greater than 10MΩ. If water ingress marks are present, dry the connector with compressed air and clean it with electrical 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 at the power supply output terminal on the IPB harness connector. If continuity exists, disconnect the IPB connector and measure the resistance to ground at 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 (soldering + 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 at 10-40 km/h) to confirm the right front wheel speed signal synchronizes with the other wheel speeds and the ABS self-check shows no abnormalities.
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 Atto 8 Fault Codes
B1108For the BYD Song MAX (2017–2019), DTC B1108 indicates a short circuit in the PM2.5 air quality detection module (dust sensor) or its wiring harness. The sensor uses laser scattering to detect in-cabin and outside PM2.5 concentrations and transmits data to the HVAC ECU via the LIN bus or an analog signal. Short circuit conditions include: 1) Sensor power supply wire (+5V/+12V) shorted to ground 2) Signal wire shorted to power or ground 3) Short circuit in the sensor's internal photoelectric detection circuit This fault prevents the automatic climate control from switching between fresh air and recirculation based on air quality. The system enters fail-safe mode (typically forced recirculation). Severe short-circuit current can destroy the HVAC ECU sampling circuit. The system classifies this as a Level 3 severe fault and restricts vehicle operation to prevent electrical fires or controller damage. For other BYD models (such as the Qin EV, E5, and Song DM), B1108 indicates a driver-side sunload sensor fault, reflecting differences in DTC definitions across models.B110811This DTC indicates a short circuit in the air conditioning system PM2.5 air quality sensor (rapid detector). Specifically, abnormal continuity exists between the sensor power supply circuit or signal output circuit and body ground or battery positive. This causes the control module (ACU/air conditioning controller) to detect abnormal current or a voltage signal outside the valid range (typically 0V or supply voltage). The PM2.5 sensor monitors internal and external particulate concentrations, providing the data the automatic air conditioning system uses to switch between fresh air and recirculation modes. A short circuit disables the air quality monitoring function. This fault may force the air conditioning system into recirculation protection mode and trigger related thermal management system faults, as the air conditioning system acts as a key actuator in vehicle thermal management. In severe cases, the short circuit current can damage the internal sampling circuit of the air conditioning controller or overheat the wiring harness.B1109DTC B1109 indicates an open circuit in the communication line between the air conditioning system PM2.5 air quality sensor (dust concentration sensor) and the air conditioning control unit (AC ECU), or an open circuit within the sensor internal circuitry. Typically located in the air conditioning intake duct, this sensor monitors real-time PM2.5 particle concentration inside and outside the vehicle. It provides data to the automatic air conditioning system for intelligent switching between fresh air and recirculation modes and for controlling the air purification device. During an open circuit fault, the AC ECU cannot receive the air quality signal, triggering the system fail-safe mode. Symptoms typically include failure of the automatic recirculation function, abnormal air purification indicator light operation, or abnormal air quality data displayed on the air conditioning panel. Severe cases may compromise the cabin environment control strategy, but do not directly affect vehicle driving safety.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.
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.