AU
C051500

DTC C051500 indicates the IPB (Intelligent Integrated Braking System) detected a short circuit to battery positive (B+) in the right rear wheel speed sensor power supply circuit — Qin Plus

Braking System

DTC C051500 indicates the IPB (Intelligent Integrated Braking System) detected a short circuit to battery positive (B+) in the right rear wheel speed sensor power supply circuit.

This fault occurs when abnormal electrical continuity develops between the sensor power line (typically a 12V supply) and the vehicle constant power supply or the IPB internal power output stage, causing an abnormal voltage increase or current overload.

The IPB control unit monitors the supply circuit voltage and current characteristics.

Upon detecting a short circuit, it triggers a protection mechanism and cuts power to the circuit to prevent hardware damage.

This fault causes the loss of the right rear wheel speed signal, disabling or degrading ABS, ESP, TCS, EPB, and Automatic Emergency Braking (AEB) functions, which severely compromises driving safety.

The '00' suffix in the DTC typically indicates an active, hard fault (non-intermittent).

The C051500 fault code on the Qin Plus indicates a high-severity short to battery positive in the right rear wheel speed sensor power supply circuit. This can cut the sensor signal and affect ABS, ESP, TCS, EPB, and AEB functions. Common causes include damaged wiring insulation or water/corrosion in the sensor connector. The recommended fix is to visit an authorised dealer for diagnosis and repair. Typical repair cost data is available from recorded cases.
5
Cases Logged
5
Causes
Likely Causes — Qin Plus
  • 1Right rear wheel speed sensor wiring harness insulation damage: Long-term vibration and friction damage the harness at the rubber grommet where it passes through the body floor or suspension control arm. The power supply wire contacts an adjacent constant power circuit (such as the tail light or fuel pump power supply), causing a short circuit.
  • 2Sensor connector water ingress and corrosion: Driving through water, direct spraying from a high-pressure washer, or poor sealing causes an internal short circuit in the connector, shorting the power supply terminal to an adjacent high-potential terminal or the metal housing.
  • 3Wheel speed sensor internal circuit breakdown: A damaged internal voltage regulator circuit or Hall element shorts the power input terminal to the signal output terminal or housing, creating a reverse short circuit in the power supply circuit.
  • 4IPB control unit internal power module fault: The output stage of the wheel speed sensor power supply chip (LDO or DC-DC) inside the IPB breaks down, causing a continuous high voltage output or internal short circuit. This condition usually accompanies similar faults in other wheel speed sensors controlled by the same IPB.
  • 5Wiring harness damage caused by improper modification or accident repair: Improperly splicing wires to draw power when installing aftermarket devices (such as dash cams or reversing sensors), or incorrectly wrapping the wiring harness during rear-end accident repairs, resulting in a crushed or misconnected power wire.
What To Do
  • 1
    Safety Preparation and Fault Confirmation: Use VDS2000 or Launch X431 to read all fault codes. Confirm if only C051500 is present or if other wheel speed sensor faults, such as C051400 (short to ground), accompany it. Record freeze frame data (vehicle speed, temperature, and voltage at the time of the fault). Check the IPB software version and verify there are no related Technical Service Bulletins (TSB).
  • 2
    Visual and connector inspection: Raise the vehicle, remove the right rear tyre, and inspect the wheel speed sensor connector (usually located near the steering knuckle or brake caliper) for signs of water ingress, corrosion, looseness, or deformed pins. Follow the wiring route and inspect the wiring harness sheath for damage. Focus on bends passing through the body floor panel and suspension control arm.
  • 3
    Power supply voltage and resistance measurement: Turn the ignition switch OFF. Disconnect the right rear wheel speed sensor connector. Measure the resistance to ground at the connector-side power supply pin (usually pin 1 or 2; refer to the wiring diagram): normal resistance is greater than 10MΩ. If the resistance is too low, the circuit is shorted to power. Turn the ignition switch ON. Measure the voltage at this pin: normal voltage is 12V ± 0.5V. If the measured voltage equals battery voltage (above 12.6V) and has direct continuity to the battery positive terminal, this confirms a short circuit.
  • 4
    Wiring insulation and continuity test: Disconnect the right trunk wiring harness connector (usually located near the right rear fender liner) to divide the circuit into the 'sensor-to-body transition section' and the 'body-to-IPB section'. Use a megohmmeter to measure the insulation resistance of the power wire to the vehicle body and to other power wires to isolate the faulty section. Check the IPB control unit connector (located near the engine compartment firewall) for water ingress or corrosion.
  • 5
    Component replacement verification: If wiring insulation is normal, replace the right rear wheel speed sensor (typical part number 3630200-00; verify model compatibility) and test. If the fault persists after replacing the sensor and verifying the wiring harness is normal, the fault indicates a damaged internal power supply module in the IPB control unit. Replace the IPB assembly (requires bleeding, calibration, and coding).
  • 6
    Repair verification and functional test: After repairing or replacing the faulty component, clear the fault code and perform a road test (vehicle speed must exceed 40km/h to activate the wheel speed signal self-check). Use a diagnostic tool to read the wheel speed sensor live data stream. Confirm the right rear wheel speed matches the other wheel speeds without spikes or dropouts. Verify the ABS, ESP, and EPB functions operate normally, and confirm the fault light is off.
Real-World Cases
BYD DTC AI Analysis

Song PLUS DM-i: Right rear wheel speed sensor power supply short circuit after water ingress

✓
2022 Song PLUS DM-i. ABS and ESP lights stayed on after driving through water. Read DTC C051500. Inspection found obvious water stains and verdigris inside the right rear wheel speed sensor connector; the power supply pin was conducting to the connector housing. Water had seeped through the connector seal during wading, causing the power terminal to short to ground (body)—misdiagnosed as a short to power (or actually shorted to the internal power wire). Cleaned the connector pins, applied conductive grease, replaced the sensor (possible internal damage), and resealed the waterproofing. Fault resolved.
BYD DTC AI Analysis

Worn wiring harness sheath caused intermittent short circuit

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2021 Song Pro DM. ESP warning light occasionally illuminates on rough roads; intermittent DTC C051500. On the lift, found the right rear wheel speed sensor harness worn at the rubber grommet where it passes through the suspension arm. Internal insulation had worn through, allowing the power wire to contact an adjacent constant-power reverse light wire. Static measurements normal, but resistance varied when shaking the harness. Repair: Repaired the damaged harness, separated the routing to avoid interference, and added an abrasion-resistant sleeve. Fault has not reoccurred.
BYD DTC AI Analysis

Internal fault in the IPB control unit caused abnormal power supply to multiple sensors.

✓
2023 Seal. DTCs C051500 and C051100 appeared after rear-end collision repairs (left rear wheel speed sensor supply short circuit). Wiring measured normal on both sides, but supply voltage read 14.5V (battery voltage), suggesting IPB internal voltage regulator damage. Traced to a flat 12V battery during the accident; jump starter connected with reversed polarity, causing surge damage to the IPB power module. Replaced the IPB integrated brake assembly, performed hydraulic bleeding, longitudinal sensor calibration, and wheel speed sensor signal learning. Fault resolved.
BYD DTC AI Analysis

Aftermarket reversing sensors incorrectly connected, causing short circuit

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2022 Song MAX. Owner installed a reversing camera at a non-authorized shop; DTC C051500 appeared the next day. Inspection found the installer cut into the right rear sill harness to draw power and mistakenly bridged the reverse light supply to the wheel speed sensor power feed, causing high current to enter the sensor circuit. Removed the non-compliant wiring, repaired the damaged factory harness (replaced the entire section to eliminate risks), and restored the original circuits. Explained the risks of unauthorized modifications to the owner.
BYD DTC AI Analysis

Sensor internal short triggered IPB protection

✓
2020 Han EV. C051500 triggered suddenly at 60,000 km. Found 0.5Ω short between the sensor connector supply pin and ground. Disconnected the sensor; harness side tested normal with 12V supply and infinite resistance to ground. Disassembled the sensor and found the internal Hall element burnt with supply and ground terminals shorted. Suspected cause: sensor ageing or internal Zener diode breakdown. Replaced the right rear wheel speed sensor (genuine part), cleared the fault codes, and road test returned to normal. Also check tire balance to rule out long-term overheating from abnormal tire vibration causing premature sensor ageing.
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.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.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.B173A1ADTC B173A1A indicates the right middle-row side airbag (typically located on the side of the right second-row seat or inside the C-pillar trim panel) igniter circuit resistance measures 0 Ω. In the Supplemental Restraint System (SRS), normal airbag igniter resistance ranges between 2.0 and 5.0 Ω. A resistance of 0 Ω indicates a short to ground or a short between circuit wires, preventing the Airbag Control Unit (ACU) from establishing a normal monitoring circuit. This safety-critical fault prevents the airbag from deploying during a collision, continuously illuminates the instrument panel SRS warning lamp, and may force the entire airbag system into fail-safe mode.B173BDTC B173B indicates an abnormal electric A/C compressor speed feedback signal or a communication fault between the compressor controller and the motor. In BYD new energy models (e.g., Tang, Song, Qin, and Yuan series), this DTC belongs to the HVAC subsystem within the Body Control system and specifically involves the electric compressor closed-loop control circuit. The ECU sets this DTC when the compressor controller (IPM) fails to receive a valid pulse signal from the Hall speed sensor for more than 3 continuous seconds, or when the deviation between the detected actual speed and the target commanded speed exceeds the calibrated threshold (typically >500 rpm). This fault forces the A/C system into fail-safe mode and stops compressor operation. Symptoms include a complete lack of cooling, intermittent cooling, or a sharp decrease in cooling performance. The instrument cluster A/C warning lamp may also illuminate. Prolonged operation with this fault can degrade high-voltage system insulation or cause controller overcurrent damage.
Common problems reported for Qin Plus →Qin Plus 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.