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 — Atto 8

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.

The C055600 fault code on the Atto 8 indicates the right front wheel speed sensor does not match the IPB braking system’s calibration. Severity is medium, as ABS, ESC, AEB, and energy recovery may be disabled while basic braking remains. Common causes include a non-genuine sensor or an incorrect hub bearing encoder ring. Visit an authorised dealer to verify parts and calibration. Typical repair cost data is available from recorded cases.
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Cases Logged
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Causes
Likely Causes — Atto 8
  • 1Non-genuine aftermarket wheel speed sensor installed; resistance value or signal characteristics do not match factory calibration (original is typically a 1200-1600Ω active sensor; mistakenly installed an 800-1200Ω passive sensor).
  • 2Installing 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 (e.g., installing a 46-pole Song Pro ring instead of the required 48-pole Song PLUS DMi ring).
  • 3Outdated IPB control module software fails to recognize the new sensor communication protocol (common on 2021 Song PLUS DMi models combining early software versions with later improved replacement sensors).
  • 4Incorrect sensor wiring harness connector pin assignment or incompatible connector type (e.g., mistakenly connecting an active sensor to a passive wiring harness circuit, causing a power supply voltage mismatch)
  • 5Failure to perform 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. Verify the deviation range of the sensor signal voltage and resistance from the calibrated values at the time of the fault.
  • 2
    Raise the vehicle and check the right front wheel speed sensor part number (usually stamped on the sensor body). Cross-reference the EPC system to verify the part number 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: 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 (the Song PLUS DMi should output 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 IPB EEPROM.
  • 6
    After completing configuration, perform 'Steering Angle Sensor Calibration' and 'Yaw Rate Sensor Calibration' (due to IPB system linkage). Clear fault codes and perform a road test to confirm ABS/ESC functions operate normally and no fault codes return.
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 Atto 8 Fault Codes
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.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.B110B07This fault code indicates abnormal operation of the internal air pump (sampling pump) in the PM2.5 air quality detection module. The PM2.5 detector uses the laser scattering principle to measure particulate concentration and requires a built-in air pump to draw ambient air into the detection chamber at a constant flow rate. The ECU sets this code when it detects an open or short in the air pump drive circuit, abnormal current (stall or free-running), or abnormal speed feedback. This fault causes the automatic air conditioning system to lose air quality sensing capability, preventing automatic switching between fresh air and recirculation modes. The instrument cluster air quality display may show '--' or a fixed value, but the fault does not affect the vehicle powertrain or basic air conditioning cooling and heating functions.B173CDTC B173C indicates the Supplemental Restraint System (SRS) detects the Right Second Row Side Airbag squib circuit resistance exceeds the calibrated threshold (typically >4.5Ω). This fault is an active diagnostic result of the SRS system, indicating a high-resistance condition in the circuit between the Airbag Control Unit (ACU) and the airbag module. Causes for excessive resistance include increased contact resistance, a partially broken wiring harness, terminal oxidation, or an aging squib wire inside the airbag module. This fault causes the system to mark the airbag circuit as 'unreliable', meaning the airbag may fail to deploy during a collision. The fault typically illuminates the instrument cluster airbag warning light (SRS light) continuously, and some models also sound a warning buzzer.
Common problems reported for Atto 8 →Atto 8 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.