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 — Seal U

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).

5
Cases Logged
5
Causes
Likely Causes — Seal U
  • 1Right rear wheel speed sensor wiring harness insulation damaged: Long-term vibration and chafing at the rubber grommet where the harness passes through the body floor or suspension arm damages the insulation, shorting the power supply wire to an adjacent permanent live circuit (e.g., tail light power, fuel pump power).
  • 2Sensor connector water ingress and corrosion: Vehicle wading, direct high-pressure washing, 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: Damage to the internal voltage regulator circuit or Hall element shorts the power input terminal to the signal output terminal or housing, creating a reverse short in the power supply circuit.
  • 4IPB control unit internal power module fault: Output stage breakdown of the internal wheel speed sensor power supply chip (LDO or DC-DC) causes continuous high voltage output or an internal short circuit. Similar faults in other wheel speed sensors controlled by the same IPB usually accompany this condition.
  • 5Wiring harness damage from improper modification or accident repair: Improper wire tapping for power when installing aftermarket equipment (such as dash cams or reversing sensors), or improper harness wrapping during rear-end collision repairs, crushing or misconnecting the power supply wire.
What To Do
  • 1
    Safety Preparation and Fault Confirmation: Use VDS2000 or Launch X431 to read all fault codes. Confirm if C051500 occurs alone or with other wheel speed sensor faults, such as C051400 (short to ground). Record freeze frame data (vehicle speed, temperature, and voltage at time of fault). Check the IPB software version and verify no related technical updates (TSB) apply.
  • 2
    Visual and connector inspection: Raise the vehicle, remove the right rear wheel, and inspect the wheel speed sensor connector (usually located near the steering knuckle or brake caliper) for water ingress, corrosion, looseness, or deformed pins. Follow the wiring route and inspect the harness sleeve for damage, focusing on the bent sections passing through the vehicle floor pan and suspension control arm.
  • 3
    Power supply voltage and resistance measurement: Turn off the ignition, disconnect the right rear wheel speed sensor connector, and measure the resistance to ground at the power supply pin on the connector side (usually pin 1 or pin 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 on the ignition and measure the voltage at this pin. Normal voltage is 12V ± 0.5V. A reading equal to battery voltage (above 12.6V) with direct continuity to the battery positive terminal 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) and 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 supply wire to the vehicle body and to other power wires to progressively narrow down 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 circuit insulation is normal, replace the right rear wheel speed sensor (typical part number 3630200-00; verify vehicle model compatibility) and test. If the fault persists after replacing the sensor and verifying the wiring harness is normal, this 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 (speed must exceed 40 km/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 and shows no fluctuation. Test the ABS, ESP, and EPB functions for normal operation, 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

✓
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

✓
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 Seal U 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.