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 — Qin Plus

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.

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Cases Logged
5
Causes
Likely Causes — Qin Plus
  • 1Damaged right rear wheel speed sensor wiring harness insulation: Stones striking the vehicle underbody during driving rupture the harness sheath, or loose harness retaining clips cause long-term friction against suspension components. This exposes the power supply wire copper core, causing it to contact metal parts of the vehicle body.
  • 2Wheel speed sensor internal short circuit: Internal Hall element or capacitor breakdown creates continuity between the power supply terminal and the sensor housing (ground). Common causes include sensor aging, overheating, or manufacturing defects.
  • 3Water ingress and corrosion in the wiring harness connector: Wading or direct high-pressure spraying in the right rear wheel area during car washing causes the sensor plug seal to fail. This creates an electrolytic conductive path between the pins, short-circuiting the power supply pin to the ground pin.
  • 4IPB control module internal drive circuit fault: The constant current source or voltage regulator chip inside the IPB module supplying power to the wheel speed sensors suffers electrical breakdown, causing the output terminal to short to ground. This fault typically triggers simultaneous power supply short circuit fault codes for multiple wheel speed sensors.
  • 5Wiring harness damage caused by accident or modification: The vehicle suffered a right-rear collision and improper routing during repairs pinched the wiring harness; or fixing screws pierced the wiring harness during later modifications, such as installing reversing sensors or mud flaps.
What To Do
  • 1
    Safety preparation and fault confirmation: Use VDS or a dedicated diagnostic tool to read all fault codes; confirm if 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 was stationary when the fault occurred (to rule out electromagnetic interference during 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 is greater than 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. Locate the right rear wheel speed sensor power supply pin on the IPB module side (located in the engine compartment or cabin front bulkhead) and measure its resistance to ground. Normal resistance exceeds 10MΩ; a reading of 0-5Ω confirms a short to ground. Use a multimeter in continuity mode to measure harness continuity section by section. Focus on bent sections where the harness passes through body panel holes and near the suspension spring seat.
  • 4
    Short circuit location and repair: If testing confirms a wiring harness short circuit, progressively peel back the harness protective sleeve from the IPB module toward the wheel, focusing on the firewall wiring grommet and rear wheel arch liner area. Upon locating the damage, if minor (single wire damage), insulate the area using a double layer of waterproof heat-shrink tubing. If multiple wires show damage or severe copper core oxidation, replace the right rear wheel speed sensor wiring harness assembly (part number usually starts with CJ). Check and replace damaged harness retaining clips. Maintain a minimum 20mm clearance from moving parts.
  • 5
    IPB module verification and testing: If the wiring harness and sensors 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 has a short to ground, replace the IPB assembly. Perform coding, matching, and longitudinal acceleration sensor calibration. After repair, clear the fault codes and perform a road test (vehicle speed above 40km/h). Verify the wheel speed data stream is normal and the fault code does not return. 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

✓
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

✓
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 Qin Plus 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.