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 6 EV

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.

The C000200 fault code on the Seal 6 EV indicates a medium-severity fault in Traction Control System Control Valve A inside the IPB braking module. It can reduce or disable traction control, especially during acceleration on slippery roads. Common causes include a sticking hydraulic valve from dirty brake fluid or debris, or a failed solenoid coil/wiring fault. 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
5
Causes
Likely Causes — Seal 6 EV
  • 1Mechanical sticking of TCS control valve A inside the IPB electro-hydraulic control module: Impurity buildup from overdue brake fluid replacement, or debris from valve spool wear, obstructs valve spool movement inside the valve body and prevents 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: Valve drive pins in the IPB module 32-pin or 48-pin main connector are backed out, oxidized, or loose, interrupting signal transmission or causing excessive voltage drop.
  • 5Software calibration error: Outdated IPB control software sets an incorrect signal acquisition threshold for the valve position sensor, triggering a false fault (use VDS1000 or a diagnostic tool to flash the IPB software to the latest version).
What To Do
  • 1
    Safety preparation and initial inspection: Shift the vehicle into P and apply the parking brake. Use the diagnostic tool to read the complete fault codes and freeze frame data. Record the vehicle speed, wheel speed, and brake pedal status at the time of the fault. Inspect the IPB electro-hydraulic module for leaks or impact damage. Check the brake fluid level and colour (replace 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 is less than 1 Ω). Measure the solenoid valve coil resistance (standard value is typically 2-8 Ω; compare with C000204 circuit control valve 2 for reference).
  • 3
    Hydraulic system diagnosis: Connect the diagnostic tool and run 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 coil or ECU drive is faulty. If the sound occurs but the fault code persists, suspect a sticking valve spool or a faulty position sensor.
  • 4
    Brake fluid replacement and bleeding: If the brake fluid is contaminated, completely replace it with DOT 4 or DOT 5.1 brake fluid and electronically bleed the IPB system (use a dedicated diagnostic tool to trigger the hydraulic pump and valves, eliminating air locks).
  • 5
    Software flash and calibration: Use the dedicated BYD 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 preceding steps fail, diagnose an internal fault in the IPB electro-hydraulic control module and replace the complete IPB assembly (verify the spare part number based on the vehicle model, e.g., the specific part number for the Song PLUS DM-i). After replacement, perform module matching, bleed the system, and clear all fault codes. Road test: Test TCS intervention during hard acceleration on a slippery surface 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

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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

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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 6 EV 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.B1737DTC B1737 indicates the Supplemental Restraint System (SRS) detected abnormal continuity between the right middle-row side airbag squib circuit (typically the second-row right seat side airbag or right curtain airbag) and the vehicle power supply (B+, battery positive). The SRS ECU monitors the airbag inflator resistance via an internal current source (normal resistance: 2.0–3.0 Ω). If the ECU detects the voltage across the inflator circuit remaining close to battery voltage (>5 V and approaching 12 V) instead of the expected low potential or floating state, it identifies a short to power. This fault prevents the airbag from deploying normally during a collision because the short circuit bypasses the firing current. In extreme cases, abnormal current can cause unintended deployment, posing a severe safety hazard.B173BDTC B173B indicates an abnormal electric A/C compressor speed feedback signal or a communication fault between the compressor controller and the motor. In BYD new energy models (e.g., Tang, Song, Qin, and Yuan series), this DTC belongs to the HVAC subsystem within the Body Control system and specifically involves the electric compressor closed-loop control circuit. The ECU sets this DTC when the compressor controller (IPM) fails to receive a valid pulse signal from the Hall speed sensor for more than 3 continuous seconds, or when the deviation between the detected actual speed and the target commanded speed exceeds the calibrated threshold (typically >500 rpm). This fault forces the A/C system into fail-safe mode and stops compressor operation. Symptoms include a complete lack of cooling, intermittent cooling, or a sharp decrease in cooling performance. The instrument cluster A/C warning lamp may also illuminate. Prolonged operation with this fault can degrade high-voltage system insulation or cause controller overcurrent damage.
Common problems reported for Seal 6 EV →Seal 6 EV 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.