AU
C006A02

DTC C006A02 indicates a functional failure or abnormal signal from the combined inertial sensor (typically an integrated yaw rate and lateral/longitudinal acceleration sensor) in the IPB (Intelligent Electro-Hydraulic Braking) system — Seal U

Braking System

DTC C006A02 indicates a functional failure or abnormal signal from the combined inertial sensor (typically an integrated yaw rate and lateral/longitudinal acceleration sensor) in the IPB (Intelligent Electro-Hydraulic Braking) system.

This sensor typically mounts in the vehicle center tunnel (under the armrest) near the center of gravity.

It acts as the core sensing component for the ESC (Electronic Stability Control), ABS (Anti-lock Braking System), TCS (Traction Control System), and AEB (Automatic Emergency Braking) systems.

When this fault triggers, the IPB ECU cannot obtain accurate vehicle attitude, lateral acceleration, and yaw rate data, causing these active safety functions to degrade or fail completely.

This failure risks a loss of vehicle stability control; therefore, the system classifies it as a Level 3 severe fault.

5
Cases Logged
5
Causes
Likely Causes — Seal U
  • 1Damaged MEMS chip or signal processing circuit inside the combined sensor, resulting in output signal drift or complete loss of signal.
  • 2Sensor wiring harness open circuit, short circuit, or short to ground/power supply, particularly damage to the wiring harness near the centre tunnel caused by water ingress, abrasion, or audio/seat modifications.
  • 3Sensor mounting bracket looseness, deformation, or installation angle offset (exceeding ±3°), causing an inertial measurement reference error.
  • 4Abnormal 5V reference voltage or ground circuit from the IPB ECU to the sensor (voltage below 4.8V or above 5.2V)
  • 5Extreme temperature conditions (typical sensor operating temperature: -40°C to 85°C) or physical sensor damage after a severe vehicle collision.
What To Do
  • 1
    Use the VDS2000/VDS3100 diagnostic tool to access the IPB system and read the freeze frame data. Verify the vehicle speed, lateral acceleration value, and sensor voltage status at the time of the fault.
  • 2
    Visually inspect the combined sensor installation under the center tunnel (usually located at the gear selector base or under the seat). Verify the fixing bolt torque (standard: 8-10 N·m) and check the bracket for deformation.
  • 3
    Disconnect the sensor connector and measure the harness side: Pin 1 (power supply, 5V ± 0.2V), Pin 2 (ground, <0.1Ω), and Pins 3/4 (CAN-H/CAN-L, approx. 2.5V). Verify the power supply and communication circuits are normal.
  • 4
    Check the sensor connector terminals for oxidation or push-back, and measure the sensor resistance (refer to the workshop manual for standard values; typical yaw rate sensor resistance is approximately 200-400Ω).
  • 5
    If the wiring is normal but the fault persists, replace the combination sensor (part numbers usually start with SC- or 3A-; verify vehicle model compatibility). After replacement, perform the sensor calibration procedure.
  • 6
    Perform calibration: Park the vehicle on level ground. Use the diagnostic tool to enter the 'Sensor Calibration' function and follow the prompts to complete the zero-point calibration of the yaw rate sensor and acceleration sensor (takes approximately 30 seconds; keep the vehicle stationary).
  • 7
    Clear the fault code and perform a road test including straight-line acceleration, braking, and turning. Verify the ESC/ABS warning lamp is off and fault code C006A02 does not return.
Real-World Cases
BYD DTC AI Analysis

Aftermarket audio modification caused wiring harness crush damage on Song PLUS DMi

✓
A 2021 Song PLUS DMi with 20,000 km had both ABS and ESC warning lights lit. Scanned DTC C006A02. The owner had recently modified the center console audio. When removing the armrest, they failed to secure the combined sensor wiring harness, leaving it to be pinched and abraded by the audio bracket. The internal copper wires fractured while the insulation remained partially intact, causing an intermittent open circuit. Re-taped the harness, rerouted it to avoid sharp metal edges, and secured it with cable ties at the factory mounting points. Cleared the fault codes and calibrated the sensor. Fault resolved.
BYD DTC AI Analysis

Internal short circuit in sensor after water ingress

✓
The day after driving through water approximately 40 cm deep, the dashboard displayed 'Braking system fault' and the scanner logged DTC C006A02. Inspection found the combination sensor mounted beneath the floor; although fitted with an external plastic shield, seal deterioration had allowed water to penetrate internally. Insulation resistance measured 0.5 MΩ (specification >10 MΩ), confirming an internal short circuit. After replacing the sensor, we performed G-sensor offset learning and yaw rate sensor calibration with the scanner. Road testing confirmed normal ESC function.
BYD DTC AI Analysis

Sensor calibration not performed after accident repair

✓
Following front-end collision repair (front subframe replacement), the technician did not calibrate the chassis system. Approximately 50 km after delivery, the instrument cluster displayed brake system fault DTC C006A02. Inspection revealed impact during the accident had shifted the combined sensor mounting position slightly (approximately 5°). Physical connections remained intact, but the inertial reference deviation produced abnormal signals. Solution: Retightened the sensor mounting bolts to 9 N·m and performed 'Longitudinal Acceleration Sensor Calibration' and 'Yaw Rate Sensor Calibration' via VDS. DTC cleared and did not return.
BYD DTC AI Analysis

Sensor signal drift in low temperature conditions

✓
Northern winter (-20°C ambient). After cold start, ESC warning light illuminated intermittently after ~5 minutes of driving. Scan tool read C006A02 (intermittent). Fault cleared once warm. Checked sensor power and ground — normal. Suspected internal MEMS element deterioration at low temperatures. Replaced sensor (same model, upgraded software version) and retested in climate chamber at -25°C. Fault did not recur. Root cause: Temperature compensation algorithm defect in early batch sensors. Replaced with improved sensor.
BYD DTC AI Analysis

Terminal backed out of connector causing poor contact

✓
Driving on rough roads caused the ESC warning light to illuminate intermittently. The scan tool showed stored fault code C006A02. Inspection of the combined sensor connector revealed terminal No. 3 (CAN-H) had backed out slightly, causing poor contact with the socket and momentary open circuits under vibration. Extracted the terminal with a removal tool, adjusted the locking tab tension, and reinserted it until it clicked. Applied conductive grease to enhance contact. Cleared the codes and tested by driving continuously over speed bumps; the fault did not return.
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.