AU
C003200

This DTC indicates the IPB (Intelligent Integrated Brake Control Unit) detects an abnormal supply voltage to the left front wheel speed sensor — Seal U

Braking System

This DTC indicates the IPB (Intelligent Integrated Brake Control Unit) detects an abnormal supply voltage to the left front wheel speed sensor.

Specifically, the ECU detects the sensor supply circuit voltage (typically 12V battery voltage or 5V reference voltage) falls outside the normal threshold range (e.g., below 9V, above 16V, or deviating from the standard value by more than ±0.5V), or detects an open circuit, short to ground, or short to power in the supply circuit.

This fault causes a missing or distorted left front wheel speed signal, triggering degradation protection in the ABS, ESC, and EPB systems.

It affects regenerative braking efficiency, Automatic Emergency Braking (AEB), and vehicle stability control functions.

In extreme cases, it may extend braking distance or cause the vehicle to pull to one side.

The C003200 fault code on the Seal U indicates abnormal supply voltage to the left front wheel speed sensor, which can affect ABS, ESC, EPB, regenerative braking, AEB, and stability control. Severity is medium, as braking performance or stability assistance may be reduced. Common causes include damaged or shorted sensor wiring near the suspension/fender liner, or a faulty wheel speed sensor. The recommended fix is to visit an authorised dealer for diagnosis and repair. Typical repair cost data is available.
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Cases Logged
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Causes
Likely Causes — Seal U
  • 1Open circuit, chafing, or short to ground in the left front wheel speed sensor wiring harness (especially at moving sections routed along the suspension control arm and fender liner).
  • 2Shorted or burnt-out internal coil in the wheel speed sensor body, causing excessive supply current and a voltage drop.
  • 3Internal power supply drive circuit fault in the IPB control unit (e.g., damaged MOSFET, damaged LDO voltage regulator chip, or cold solder joint)
  • 4Wiring harness connector (located near the left front wheel hub or engine compartment firewall) is loose, has a backed-out terminal, or is oxidized due to water ingress, causing excessive contact resistance.
  • 5Poor body ground circuit (corroded or loose ground point G101), causing abnormal reference potential in the power supply circuit.
What To Do
  • 1
    Use the VDS2000/VDS3000 diagnostic tool to read all fault codes and freeze frame data. Check for accompanying codes C003108 (signal fault) or C003204 (circuit fault), and record the vehicle speed and ambient temperature at the time of the fault.
  • 2
    Raise the vehicle. Visually inspect the condition of the left front wheel speed sensor connector (located near the shock absorber or brake hose bracket). Check the pins for corrosion, backing out, or water ingress, and test the connector sealing.
  • 3
    Disconnect the left front wheel speed sensor connector (usually 2-wire: power+ and signal/ground). Turn the ignition switch to ON. Use a multimeter to measure the voltage between the harness-side power supply pin and ground. Normal voltage is battery voltage (12V±0.5V). If equipped with a 5V sensor, the voltage is 5V±0.25V.
  • 4
    If the voltage is abnormal (0V, below 9V or above 16V), follow the wiring route and check harness continuity. Inspect the harness sleeve for wear, focusing on the fender liner retaining clips and the movement range of the upper and lower suspension control arms. Measure the power wire to ground resistance (should be >10MΩ).
  • 5
    If the wiring harness voltage is normal, measure the sensor resistance (normal range: 1.0 kΩ–1.5 kΩ at 20°C). A resistance of <100 Ω or >5 kΩ indicates an internal short or open circuit. Replace the wheel speed sensor (typical part number SA-3630100 or vehicle-specific equivalent). During installation, apply an appropriate amount of grease and tighten to the specified torque (8–12 N·m).
  • 6
    If the sensor and wiring harness are normal but the IPB output terminal voltage is abnormal, disconnect the IPB module connector and measure the continuity between the IPB power supply output terminal and the sensor connector. If continuity is normal but the output voltage is abnormal, the internal IPB power supply module is faulty. Replace the IPB integrated brake assembly, then bleed and calibrate the brake system according to the repair manual.
  • 7
    After completing the repair, clear the fault code and perform a road test: drive in a straight line at speeds above 20 km/h, use the diagnostic tool to read the data stream for the four wheel speed sensors, confirm the left front wheel speed matches the other wheel speeds without fluctuation, verify the ABS and ESC warning lights are off, and test the automatic emergency braking function for normal operation.
Real-World Cases
BYD DTC AI Analysis

Chafed left front wheel speed sensor wiring harness caused intermittent power loss on the Song PLUS DM-i

✓
The ABS and ESC warning lights illuminated intermittently when the vehicle entered the workshop. The scan tool retrieved DTC C003200. Inspection found the left front wheel speed sensor connector intact; measured supply voltage fluctuating between 9-12V. Further inspection revealed the wiring harness had chafed through at the fender liner retaining clip, damaging the insulation and partially breaking the copper cores. Repaired the damaged section by soldering and heat-shrink sealing the joints, rerouted the harness and added anti-chafe sleeving. Fault resolved.
BYD DTC AI Analysis

Wheel speed sensor internal short circuit pulls down supply voltage

✓
Owner reported ABS light stays on when pulling away. Active DTC C003200. Measured 12V supply from IPB to sensor harness – normal. Voltage dropped to 2V with sensor connected; disconnected sensor plug and voltage returned to normal. Sensor resistance measured 50Ω (normal ~1.2kΩ); internal coil burned and shorted. Replaced left front wheel speed sensor. Supply voltage returned to 12V. Cleared fault code; road test normal.
BYD DTC AI Analysis

IPB integrated brake unit internal power supply module damaged

✓
A Song Pro DM with 80,000 km had a recurring left front wheel speed sensor supply voltage fault. Replacing the sensor and harness made no difference. IPB output terminal X1-15 (left front wheel speed supply) measured 0 V while the other wheel speed sensor supply terminals showed 12 V. IPB power and ground were normal, pointing to a failed internal left front wheel speed supply driver MOSFET. Replaced the IPB assembly (part number EA-3535010), bled the brakes, calibrated the longitudinal acceleration sensor, and cleared the fault.
BYD DTC AI Analysis

Water entered the connector after wading, causing corrosion and poor contact.

✓
After driving through water, the ABS warning light came on. Diagnosis showed DTC C003200. Inspection found visible water staining and verdigris corrosion inside the left front wheel speed sensor connector, causing high contact resistance at the power pin (measured 15Ω, normal <0.5Ω). Fix: Cleaned the connector with electronic contact cleaner, sanded the pins with fine sandpaper, applied conductive grease, and replaced the waterproof seal. Checked the other sensor connectors on the same side preventively, performed a bleed test, and cleared the fault.
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.