AU
C000200

DTC C000200 indicates a functional fault (Fault Type 2) in TCS (Traction Control System) Control Valve A within the IPB (Intelligent Integrated Braking System) electro-hydraulic control module — Seal U

Braking System

DTC C000200 indicates a functional fault (Fault Type 2) in TCS (Traction Control System) Control Valve A within the IPB (Intelligent Integrated Braking System) electro-hydraulic control module.

This solenoid valve belongs to the high-speed switching valve array in the Hydraulic Control Unit (HCU).

It precisely regulates hydraulic pressure to the drive wheel brake calipers during TCS activation, preventing drive wheel slip during starting or acceleration. 'Fault Type 2' typically indicates mechanical binding in the valve body, abnormal solenoid coil resistance (open or short circuit), or a spool position feedback signal exceeding the calibrated threshold.

This fault causes TCS failure or performance degradation.

The vehicle may lose traction control during hard acceleration on slippery surfaces.

Extreme conditions trigger the brake system degradation mode (limp mode), limiting vehicle speed and illuminating multiple warning lights.

5
Cases Logged
5
Causes
Likely Causes — Seal U
  • 1Mechanical sticking of TCS control valve A inside the IPB electro-hydraulic control module: Overdue brake fluid replacement causes impurity buildup, or valve spool wear generates debris, restricting valve spool movement within the valve body and preventing it from reaching the target opening.
  • 2Solenoid valve coil electrical fault: Internal coil open circuit (infinite resistance) or short circuit to power/ground. Wiring harness aging, water ingress corrosion, or manufacturing defects typically cause this fault, preventing the ECU from driving the valve.
  • 3IPB control unit drive circuit fault: Damaged internal power driver chip (MOSFET or H-bridge) fails to supply sufficient drive current to the solenoid valve (typically requires 3-5A peak current).
  • 4Poor wiring harness connector contact: Backed out, oxidized, or loose valve drive pins in the IPB module 32-pin or 48-pin main connector interrupt signal transmission or cause excessive voltage drop.
  • 5Software calibration fault: Outdated IPB control software sets an incorrect signal acquisition threshold for the valve position sensor, triggering a false fault (use the VDS1000 or a diagnostic tool to flash the IPB software to the latest version).
What To Do
  • 1
    Safety preparation and initial inspection: Shift vehicle into P and apply parking brake. Read complete fault codes and freeze frame data using the diagnostic tool. Record vehicle speed, wheel speed, and brake pedal status at the time of the fault. Inspect the IPB electro-hydraulic module exterior for leaks or impact damage. Check brake fluid level and colour (replace fluid if dark or contaminated).
  • 2
    Electrical connection check: Disconnect the 12V battery negative terminal and unplug the IPB module main connector. Check the pins for corrosion, push-out, or burn marks. Measure the wiring harness continuity from the connector to the solenoid valve (normal resistance < 1Ω). Measure the solenoid valve coil resistance (standard value is typically 2-8Ω; compare with C000204 circuit control valve 2 for reference).
  • 3
    Hydraulic system diagnosis: Connect the diagnostic tool and execute the IPB hydraulic unit self-test (Active Test). Listen for a clear 'click' from TCS control valve A. If no sound occurs, measure resistance to determine if the fault is in the coil or the ECU driver. If the sound occurs but the fault code persists, suspect a stuck valve spool or a faulty position sensor.
  • 4
    Brake fluid replacement and bleeding: If the brake fluid is contaminated, completely replace it with DOT4 or DOT5.1 brake fluid and electronically bleed the IPB system (use a dedicated diagnostic tool to trigger the fluid pump and valves to ensure no air lock).
  • 5
    Software update and calibration: Use the BYD dedicated diagnostic tool (VDS1000 or VDS2000) to check the IPB software version. If an update is available, flash the software. Perform 'brake pressure sensor calibration' and 'longitudinal acceleration sensor calibration' to ensure accurate basic TCS control parameters.
  • 6
    Assembly replacement and verification: If the previous steps fail, diagnose an internal fault in the IPB electro-hydraulic control module and replace the entire IPB assembly (verify the spare part number by vehicle model; e.g., Song PLUS DM-i uses a specific part number). After replacement, perform matching, bleed the system, and clear all fault codes. Perform a road test: accelerate hard on a slippery surface to test TCS intervention and verify the fault code does not return.
Real-World Cases
BYD DTC AI Analysis

BYD Song PLUS DM-i TCS Valve Body Corrosion After Water Wading

✓
2021 Song PLUS DM-i owner reported ABS and ESC warning lights illuminated after driving in rain. Codes: C000200, C000204. Vehicle had waded through water to wheel hub centre height. Removed IPB module connector; aged seals allowed water ingress, and TCS control valve A coil pin showed green copper corrosion. Cleaned pins with precision electrical contact cleaner, applied conductive paste, resistance normalized. Cleared codes; fault returned within one week. Replaced IPB electro-hydraulic module assembly and upgraded software to post-2023 version; fault eliminated. Inspect brake system seals promptly after wading.
Original source ↗
BYD DTC AI Analysis

Qin PLUS valve spool sticking from long-term missed maintenance

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A Qin PLUS EV at 80,000 km developed a C000200 fault code with slight drive wheel slip during initial acceleration. Inspection found brake fluid unchanged for four years, dark brown with flocculent sediment. The diagnostic valve actuation test showed TCS control valve A had delayed response and dull sound. Contaminated brake fluid caused the valve spool to stick. Flushing the HCU internal passages with dedicated brake system cleaner temporarily cleared the fault, but the IPB assembly requires replacement for long-term reliability. After installing the new assembly and completing brake bleeding and calibration, TCS function returned to normal. Replace brake fluid every two years or 40,000 km.
Original source ↗
BYD DTC AI Analysis

Software update resolves Han EV IPB false positive fault

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The owner of a 2022 Han EV AWD repeatedly saw an intermittent C000200 fault code. The warning light came on intermittently, but driving remained normal. At the workshop, the code showed as history. Technicians measured the solenoid valve resistance at 5.2Ω (normal) and found no wiring harness issues. The BYD Technical Service Bulletin (TSB) confirmed that IPB controller software version V1.2 on this production batch was overly sensitive to valve response times, potentially triggering false faults from voltage fluctuations. The technician upgraded the software to V1.5 and recalibrated the brake pressure sensor. The fault has not returned. This was a software false alarm requiring no hardware replacement.
Original source ↗
BYD DTC AI Analysis

Wiring harness connector pin backed out on new BYD Dolphin

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A new Dolphin with only 3,000 km suddenly displayed "Brake System Fault" and set DTC C000200. Pin 15 (TCS Valve A Drive Positive) in the 48-pin IPB module connector had backed out slightly, causing poor contact. Assembly error—the pin wasn't fully seated and worked loose from vibration. Re-crimped the pin and applied insulating silicone grease to secure it; fault cleared. Check that IPB and other high-power module connectors are fully locked during new car PDI.
Original source ↗
BYD DTC AI Analysis

Tang DM-i: Accidental IPB activation after ABS sensor replacement causes fault

✓
While replacing the rear wheel ABS wheel speed sensor on a Tang DM-i, the technician did not disconnect the 12V battery. A tool accidentally shorted to ground, sending a surge through the IPB module. After startup, DTC C000200 set and could not be cleared. Testing showed the TCS control valve A coil was open (infinite resistance). The surge had damaged either the IPB internal drive circuit or the valve body coil. After replacing the IPB electro-hydraulic module and strictly following the power-down protocol, the technician used a diagnostic tool to perform system configuration write and coding configuration. This resolved the fault. Always disconnect the low voltage battery negative terminal before any IPB work.
Original source ↗
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.