AU
C007200

C007200 is an advanced diagnostic trouble code in the BYD Integrated Power Brake (IPB) system — Atto 8

Braking System

C007200 is an advanced diagnostic trouble code in the BYD Integrated Power Brake (IPB) system.

It indicates an abnormal thermal condition or pressure-temperature correlation in hydraulic brake circuit A (typically the front brake circuit).

The system triggers this code based on a combined assessment of real-time master cylinder pressure sensor data, the hydraulic valve body temperature prediction model, and the braking frequency algorithm.

The system records this fault when brake fluid temperature exceeds the preset threshold (typically caused by frequent braking, throttling heat generation from internal hydraulic leakage, or high ambient temperatures), or when the pressure sensor signal logically mismatches the temperature model.

This fault may degrade ESP/ABS functions, cause abnormal brake pedal feel (soft or hard), and restrict regenerative braking.

Severe cases trigger overheat protection and cut off power output.

3
Cases Logged
5
Causes
Likely Causes — Atto 8
  • 1Continuous heavy braking conditions (such as long downhill grades, aggressive driving, or frequent hard acceleration/deceleration) cause heat build-up in the brake fluid.
  • 2Aging or worn internal sealing rings in the IPB hydraulic valve body cause internal hydraulic leakage (not externally visible), resulting in throttling heat build-up.
  • 3Master cylinder pressure sensor signal drift, zero-point misalignment, or internal sensor fault sending incorrect pressure-temperature correlation data to the ECU.
  • 4Poor connection, oxidized pins, or waterproof seal failure at the IPB control unit wiring harness connector (located near the engine compartment firewall), causing signal interference.
  • 5Abnormal wheel speed sensor signal (contamination or damage) causes the ESP system to actuate frequently to regulate hydraulic pressure, generating additional heat build-up.
What To Do
  • 1
    Use VDS or a dedicated diagnostic tool to read the DTC freeze frame data. Confirm vehicle speed, brake pressure, calculated temperature, pedal travel, and driving conditions (e.g., energy recovery mode) at the time of the trigger.
  • 2
    Visually check the brake fluid level (between MAX and MIN), brake fluid color (for deterioration or blackening), and external brake lines, hoses, and wheel cylinders for physical leaks.
  • 3
    Check the IPB control unit connector (located on the left or right side of the engine compartment firewall, with a waterproof sealing cover) for secure locking, waterproof sealing ring integrity, and oxidized, backed-out, or corroded pins.
  • 4
    Perform the 'Brake Hydraulic System Bleeding' procedure (use a diagnostic tool to activate the IPB internal bleed pump) and the 'Master Cylinder Pressure Sensor Zero-Point Calibration' procedure to clear false faults caused by sensor drift.
  • 5
    Check the four wheel speed sensor signal waveforms (use an oscilloscope or diagnostic tool to read the live data stream). Clean the sensor probes and tone rings to prevent signal fluctuations from falsely activating the ESP.
  • 6
    If the fault is intermittent, perform a wiring harness wiggle test and an IPB control unit heating/cooling test to locate poor connections or internal solder joint faults.
  • 7
    If the above steps fail, measure the IPB hydraulic valve body solenoid resistance (standard value is typically 2-5Ω; refer to the repair manual for exact specifications) and insulation. If necessary, replace the IPB integrated brake assembly and flash the control software to the latest version.
Real-World Cases
BYD DTC AI Analysis

Song PLUS DM-i: Software false positive triggers multiple simultaneous DTCs (C007200+C055E00)

✓
The dashboard simultaneously illuminated the ABS, ESP and brake system warning lights, displaying "Check brake system". The scan tool retrieved DTCs C007200 (Brake temperature too high) and C055E00 (Brake hydraulic circuit A leak) among others. Brake fluid level was normal with no visible external leaks, ruling out physical leakage. Performed "Brake hydraulic system bleed" and "Pressure sensor zero calibration" using the dealership diagnostic tool, then reflashed the ESP control unit software. Fault eliminated. Root cause: IPB system pressure sensor zero drift or software logic miscalculation. Resolved without replacing any hardware.
Original source ↗
BYD DTC AI Analysis

BYD Han DM: Internal Leak in Brake Hydraulic Circuit from Aged Seal

✓
While driving, the dashboard suddenly displayed 'Brake System Fault' and ABS/ESP functions failed. DTC C055E00 (Brake Hydraulic Circuit A Leak) stored—same hydraulic circuit monitoring fault category as C007200. Lifted the vehicle and inspected the brake calipers and external lines at all four wheels; found no leaks. Removed the ABS/IPB pump and found the internal valve seals had hardened with age, causing internal brake fluid leakage (not external) within the valve body, abnormal hydraulic circulation, and localized overheating. Replaced the ABS/ESP pump assembly (using improved high-temperature seal components), performed brake bleeding and sensor calibration. Fault resolved.
BYD DTC AI Analysis

Contaminated wheel speed sensor on Tang DM triggered false ESP activation, indirectly causing hydraulic overheating.

✓
While driving at highway speeds, the ESP system triggered erroneously, causing sudden automatic braking and brake pedal shudder. The instrument cluster then displayed a brake system fault. The scan tool showed C0035 (right front wheel speed sensor signal fault), hydraulic circuit pressure anomalies, and C0072-series temperature monitoring faults. Inspection found the right front wheel speed sensor probe covered in iron debris and mud, causing signal fluctuation. This abnormal signal caused the ESP to falsely detect wheel slip, repeatedly adjusting hydraulic circuit pressure, which indirectly overheated the hydraulic valve body and triggered C007200-type temperature monitoring faults. After cleaning the wheel speed sensor probe and tone ring, resetting the IPB system and calibrating the sensors cleared the fault.
Original source ↗
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.