AU
C003200

This DTC indicates the IPB (Intelligent Integrated Brake Control Unit) detects an abnormal supply voltage to the left front wheel speed sensor — Atto 8

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.

4
Cases Logged
5
Causes
Likely Causes — Atto 8
  • 1Open circuit, chafing, or short to ground in the left front wheel speed sensor wiring harness (especially at moving sections near the suspension control arm and fender liner)
  • 2A shorted or burnt-out internal coil in the wheel speed sensor causes excessive supply current and pulls down the voltage.
  • 3Internal power supply drive circuit fault in the IPB control unit (e.g., damaged MOSFET, damaged LDO voltage regulator chip, or cold solder joint).
  • 4Loose wiring harness connector (located near the left front wheel hub or engine compartment firewall), backed-out terminals, or water ingress and oxidation, causing excessive contact resistance.
  • 5Poor body ground circuit (G101 ground point corroded or loose), 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 C003108 (signal fault) or C003204 (circuit fault) codes. Record the vehicle speed and ambient temperature at the time of the fault.
  • 2
    Raise the vehicle. Visually inspect the exterior 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. Test the connector sealing.
  • 3
    Disconnect the left front wheel speed sensor connector (typically 2-wire: power + and signal/ground). Turn the ignition switch ON. Use a multimeter to measure the voltage from the harness-side power supply terminal to 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 (0 V, below 9 V, or above 16 V), check wiring harness continuity along the routing. 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 >10 MΩ).
  • 5
    If the wiring harness voltage is normal, measure the sensor body resistance (normal range: 1.0 kΩ–1.5 kΩ at 20°C). If the resistance is <100 Ω or >5 kΩ, this indicates an internal short or open circuit in the sensor. Replace the wheel speed sensor (typical part number SA-3630100 or corresponding model number). 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 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 workshop manual.
  • 7
    After repair, clear the fault code and perform a road test: drive straight at speeds above 20 km/h, read the four wheel speed sensor data streams using the diagnostic tool, 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 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.