AU
C055600

DTC C055600 indicates the IPB (Intelligent Integrated Braking System) control module detects the hardware model or electrical characteristics of the right front wheel speed sensor do not match the system calibration parameters — Seal U

Braking System

DTC C055600 indicates the IPB (Intelligent Integrated Braking System) control module detects the hardware model or electrical characteristics of the right front wheel speed sensor do not match the system calibration parameters.

This is a configuration/calibration fault, not a simple signal fault.

By monitoring the sensor resistance, signal voltage range, pulse characteristics, or digital communication protocol, the IPB system detects the installed sensor does not match the vehicle configuration code (VIN-corresponding calibration data).

This typically occurs after installing non-genuine parts, installing a sensor from another vehicle model, or if the sensor does not match the wheel hub bearing assembly (some BYD models separate the magnetic encoder bearing from the sensor).

When this fault triggers, the IPB enters degraded mode, disables ABS, ESC, Automatic Emergency Braking (AEB), and energy recovery functions, retaining only basic hydraulic braking.

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Cases Logged
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Causes
Likely Causes — Seal U
  • 1Installed a non-genuine aftermarket wheel speed sensor with a resistance value or signal characteristics that do not match the factory calibration (mistakenly installing an 800-1200Ω passive sensor instead of the typical 1200-1600Ω active original sensor).
  • 2Mistakenly installing a part from another model during right front wheel hub bearing assembly replacement causes a mismatch in the magnetic encoder ring pole count or spacing (for example, installing a 46-pole ring from the Song Pro when the Song PLUS DMi requires a 48-pole magnetic ring).
  • 3Outdated IPB control module software fails to recognize the communication protocol of the new-version sensor (commonly occurs on 2021 Song PLUS DMi models when early software pairs with a later-installed improved replacement sensor).
  • 4Incorrect sensor wiring harness connector pin definition or incompatible connector type (e.g., mistakenly connecting an active sensor to a passive harness circuit, causing a supply voltage mismatch)
  • 5Failure to execute the IPB system sensor configuration writing (coding) or parameterization process after unauthorized vehicle repairs.
What To Do
  • 1
    Use the VDS2000/VDS3000 diagnostic tool to access the IPB system and read the freeze frame data. Confirm the deviation range of the sensor signal voltage and resistance from the calibration values at the time the fault occurred.
  • 2
    Raise the vehicle and check the right front wheel speed sensor part number (usually stamped on the sensor body). Cross-check the EPC system to verify the part matches the vehicle configuration code (e.g., Song PLUS DMi requires the 5A-36301-XX series active sensor).
  • 3
    Remove the sensor and measure the resistance. Normal values are 1.2-1.6 kΩ for an active sensor (Hall type) and 0.8-1.2 kΩ for a passive sensor (electromagnetic type). If the resistance is out of specification, replace the sensor with a genuine part.
  • 4
    Check the wheel hub bearing magnetic encoder ring: Use an oscilloscope to measure the sensor signal. Rotate the wheel and observe the number of waveform cycles (Song PLUS DMi outputs 48 pulses per revolution). If the pulse count is incorrect, replace the bearing assembly.
  • 5
    If the hardware is normal, perform the IPB system 'Sensor Parameterization' procedure: Enter Special Functions → Wheel Speed Sensor Configuration → Select the correct sensor model code (Active/Passive and number of poles) → Write to the IPB EEPROM.
  • 6
    After completing the configuration, perform 'Steering Angle Sensor Calibration' and 'Yaw Rate Sensor Calibration' (due to IPB system linkage). Clear the fault codes and road test the vehicle to confirm ABS/ESC functions operate normally and no fault codes recur.
Real-World Cases
BYD DTC AI Analysis

Song PLUS DMi: Aftermarket sensor replacement caused ESC failure

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2021 BYD Song PLUS DM-i, 32,000 km, dashboard showing ABS and ESP warning lights. VDS read C055600 (right front wheel speed sensor wrong model). Found an independent shop had replaced the right front wheel bearing with a branded aftermarket part (no magnetic encoder ring). The factory unit integrates a 48-pole magnetic encoder ring. Installed genuine BYD hub bearing assembly (PN SA3E-3103200) and ran sensor parameterization. Fault cleared.
BYD DTC AI Analysis

IPB software version mismatch causes false alarm

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BYD Song PLUS DM-i 2021. Vehicle came in for maintenance and stored DTC C055600. Confirmed the sensor was OEM and measured 1.4 kΩ resistance (normal). Found IPB control module software version 2021.08, though the vehicle had received an upgraded 2022-model wheel speed sensor under warranty (minor resistance characteristic differences). Updated IPB software to version 2022.12 and performed sensor recalibration. Fault cleared.
BYD DTC AI Analysis

Aftermarket wiring harness modification caused abnormal sensor power supply

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After sheet metal repairs to the right front fender following an accident, the vehicle set DTC C055600. Inspection found technicians had re-soldered the wiring harness during the crash repair and mistakenly connected the active wheel speed sensor power supply line (which requires 12V) to the 5V reference voltage line. This caused insufficient sensor output signal amplitude. Corrected the harness connections to restore the 12V power supply circuit and cleared the fault code.
BYD DTC AI Analysis

Wrong sensor models fitted to left and right sides (DM-i and EV variants mixed)

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While servicing both vehicles simultaneously, the technician mistakenly installed the EV's right front wheel speed sensor (passive, 900Ω) on the DMi. The DMi's IPB system expects an active sensor; startup self-test detected abnormal resistance and set C055600. Replaced the sensor with the DMi-specific active unit (1.5kΩ) and cleared the fault code. Resolved.
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.