AU
C007200

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

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.

The C007200 fault code on the Seal U indicates an abnormal temperature or pressure-temperature reading in brake hydraulic circuit A within the IPB brake system. Severity is medium, as it may affect ABS/ESP operation, brake pedal feel, and regenerative braking. Common causes include repeated heavy braking that overheats the brake fluid or internal leakage in the IPB valve body. Visit an authorised dealer for diagnosis and repair. Typical repair cost data is available.
3
Cases Logged
5
Causes
Likely Causes — Seal U
  • 1High-intensity continuous braking conditions causing brake fluid heat build-up (e.g., long downhill sections, aggressive driving, or frequent rapid acceleration/deceleration).
  • 2An aging or worn internal sealing ring in the IPB hydraulic valve body causes internal hydraulic leakage (not externally visible), leading to throttling heat build-up.
  • 3Master cylinder pressure sensor signal drift, zero-point calibration error, or internal sensor fault, transmitting incorrect pressure-temperature correlation data to the ECU.
  • 4Poor contact, 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 frequently regulate hydraulic pressure, generating excess heat build-up.
What To Do
  • 1
    Use VDS or a dedicated diagnostic tool to read the DTC freeze frame data. Confirm the vehicle speed, brake pressure value, calculated temperature, pedal travel, and driving conditions (such as whether energy recovery mode was active) at the time of triggering.
  • 2
    Visually check the brake fluid level (must be between MAX and MIN), the brake fluid colour (for deterioration or blackening), and the external brake lines, hoses, and brake calipers 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 (requires the 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, and rule out false ESP activation caused by signal fluctuations.
  • 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 (typical standard value is 2-5 Ω; refer to the workshop manual for exact specifications) and insulation. If necessary, replace the IPB integrated brake assembly and update 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

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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.

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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 Seal U Fault Codes
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.B110A02DTC B110A02 indicates the thermal management master control unit (HVAC ECU) or body control module (BCM) failed to receive valid CAN data frames from the PM2.5 air quality sensor over consecutive communication cycles (typically 500ms per cycle). The sensor typically mounts at the HVAC unit air inlet or behind the glove box and transmits real-time particulate concentration data (unit: μg/m³) to the HVAC controller via the CAN bus. The fault is essentially a communication link layer timeout. Potential causes include physical layer wiring faults, sensor power supply failures, sensor internal MCU lockup, or CAN network topology damage. Although this non-critical fault does not directly affect driving safety, it disables the intelligent air purification strategy and the automatic fresh air/recirculation switching function. In extreme cases, it triggers a thermal management system degraded mode, limiting compressor power or fixing the air flap position.B110BDTC B110B indicates a fault in the internal air pump (sampling pump) of the PM2.5 air quality detector. This pump draws cabin or outside air into the PM2.5 sensor detection chamber, enabling the laser scattering sensor to measure real-time particulate matter concentration. The air conditioning controller (or BCM) sets this DTC upon detecting an open or short circuit in the pump drive circuit, or abnormal current caused by a seized pump motor. This fault disables the "Green Clean" system, causes the instrument cluster air quality display to read abnormally or disappear, and disables the automatic fresh air/recirculation switching function. It does not affect the vehicle powertrain or core thermal management functions.B173712DTC B173712 indicates a short to power in the firing circuit of the right second-row side airbag module in the Supplemental Restraint System (SRS). Specifically, the "right second-row side airbag" typically refers to the side impact airbag located in the right B-pillar or the side of the right seat. The "12" suffix indicates a circuit short to battery positive (B+). This fault causes the following conditions: 1) The airbag may fail to ignite and deploy during a collision, resulting in a loss of side impact protection. 2) In extreme cases, unintended triggering may cause accidental airbag deployment. 3) The SRS control unit detects abnormally high circuit voltage (typically above 4.5V) and enters fault protection mode. This may disable the entire airbag system and continuously illuminate the instrument cluster airbag warning light.
Common problems reported for Seal U →Seal U 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.