AU
C055800

DTC C055800 indicates the IPB (Integrated Intelligent Braking System) control unit detects a mismatch between the digital signal protocol from the right rear wheel speed sensor (WSS) and the system preset standard — Qin Plus

Braking System

DTC C055800 indicates the IPB (Integrated Intelligent Braking System) control unit detects a mismatch between the digital signal protocol from the right rear wheel speed sensor (WSS) and the system preset standard.

Specifically, the sensor PWM (pulse-width modulation) or square-wave signal exceeds calibrated thresholds for waveform characteristics, duty cycle, frequency range, or voltage amplitude, preventing the control unit from correctly interpreting wheel speed data.

Unlike a simple signal loss (open circuit), this protocol-level communication mismatch indicates an incompatible sensor hardware version, signal distortion, or EMC interference.

When this fault triggers, wheel speed-dependent systems (ABS, ESC, TCS) enter a degraded mode.

On some models, the fault disables the automatic emergency braking system or limits vehicle speed.

The C055800 fault code on the Qin Plus indicates a right rear wheel speed sensor signal protocol mismatch detected by the IPB braking control unit. Severity is medium, as ABS, ESC, traction control, or emergency braking may be limited. Common causes include a faulty wheel speed sensor or damaged, oxidized, or poorly shielded wiring causing signal distortion. Visit an authorised dealer for diagnosis and repair. Typical repair cost data is available from 3 recorded cases.
3
Cases Logged
5
Causes
Likely Causes — Qin Plus
  • 1Wheel speed sensor component fault: Poor thermal stability of the internal Hall element or processing chip distorts the output signal waveform at high temperatures or high speeds, causing protocol verification failure.
  • 2Wiring harness and connector fault: Oxidized or backed-out sensor plug pins, or damaged wiring harness shielding causing electromagnetic interference that distorts the signal during transmission.
  • 3Mechanical installation issue: Air gap between the sensor and magnetic encoder ring (tone ring) exceeds the standard range (0.3-1.2mm), or the encoder ring is deformed, dirty, or demagnetized, causing abnormal signal amplitude.
  • 4Software/hardware version mismatch: The replacement wheel speed sensor part number does not match the hardware version specified by the vehicle VIN (e.g., different output pulse count), causing the IPB to detect a protocol error.
  • 5Internal fault in the IPB control unit: Abnormal sampling resistor or filter capacitor in the control unit input circuit causes misinterpretation of normal signals (less common).
What To Do
  • 1
    Initial diagnostic scan: Use VDS or a dedicated diagnostic tool to read all fault codes and freeze frame data. Determine if C055800 is a current fault. Record vehicle speed, temperature, and other environmental parameters at the time of the fault.
  • 2
    Visual and connection inspection: Check the right rear wheel speed sensor connector (usually located near the rear suspension) for looseness, water ingress, or oxidation. Check the wiring harness sleeve for damage, paying special attention to wear-prone areas under the chassis. Check the magnetic encoder ring for cracks, deformation, or foreign matter.
  • 3
    Electrical parameter measurement: Disconnect the sensor connector. Measure the sensor supply voltage (should be 12V±0.5V) and ground resistance (should be less than 1Ω). Measure the sensor signal wire resistance and voltage to ground. Monitor the sensor output waveform with an oscilloscope and check for noise, abnormal amplitude, or duty cycle drift.
  • 4
    Mechanical clearance check: Use a feeler gauge to measure the air gap between the sensor end face and the encoder ring. The standard value is typically 0.3-1.2 mm (refer to the repair manual for exact specifications). Check if the encoder ring radial runout exceeds the limit.
  • 5
    Component replacement and matching: If diagnostics confirm a sensor fault, replace it with a genuine part (match the part number to the VIN). Install the new sensor and tighten to the specified torque (usually 8±1N·m). On some models, use a diagnostic tool to perform the 'wheel speed sensor zero-point calibration' or 'ABS system configuration' procedure.
  • 6
    Verification test: Clear the fault code and perform a road test (including low-speed, medium-speed, high-speed, and steering conditions). Monitor the data stream to verify the right rear wheel speed signal synchronizes with the other three wheels without erratic fluctuations, and confirm the fault light does not illuminate again.
Real-World Cases
BYD DTC AI Analysis

Oxidized right rear wheel speed sensor connector on Tang DM caused signal protocol error

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ESP warning light comes on intermittently while driving; the cluster displays "Check ESP System". Speedometer needle occasionally jumps, with symptoms worse on rough roads. VDS2000 scan retrieved DTCs C055800 and C003A00. Found internal pin oxidation in the RH rear wheel speed sensor connector; measured sensor resistance at 1.8 kΩ (normal 1.5–2.5 kΩ); reluctor ring slightly deformed. Replaced RH rear wheel speed sensor (part number: 3635100-XXX), cleaned connector and applied conductive grease, straightened deformed reluctor ring section, and torqued sensor to 8 N·m. Cleared faults and road-tested 30 km; no recurrence.
BYD DTC AI Analysis

Damaged wheel speed sensor wiring harness on Song Pro causing protocol error faults

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ABS warning light stays on after startup. ABS triggers falsely during normal driving with pedal kickback, and the speed display is erratic. Scan tool showed DTCs C055800 and C055500 (multi-wheel protocol errors). Lifted the vehicle and found the wheel speed sensor wiring harness protective sleeve damaged underneath, with the signal wire shielding exposed and damaged, causing electromagnetic interference while driving. Repaired the harness, resoldered the shielding and wrapped it with waterproof tape, replaced the damaged sleeve, and replaced the right rear sensor for reliability. After repair, checked all four wheel speed signal waveforms with an oscilloscope, confirming no interference. Fault resolved.
BYD DTC AI Analysis

Qin Pro right rear wheel speed sensor thermal stability fault

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At speeds over 80km/h, ESP and ABS warning lights lit up simultaneously and the speedometer instantly dropped to zero. Lights went out after lifting off the throttle. Scan tool showed intermittent historical fault C055800. Checked connector pins—no retraction. Supply voltage 12V, normal. Oscilloscope monitoring caught the right rear wheel speed sensor signal amplitude fluctuating abnormally above 80km/h, dropping from the normal 5V peak-to-peak to below 2V. Faulty internal Hall element thermal stability. Fix: Replaced right rear wheel speed sensor assembly, air gap set to 0.8mm (within spec). Post-repair high-speed road test: 100km continuous driving, no fault codes.
Other Qin Plus 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.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.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.B173A1ADTC B173A1A indicates the right middle-row side airbag (typically located on the side of the right second-row seat or inside the C-pillar trim panel) igniter circuit resistance measures 0 Ω. In the Supplemental Restraint System (SRS), normal airbag igniter resistance ranges between 2.0 and 5.0 Ω. A resistance of 0 Ω indicates a short to ground or a short between circuit wires, preventing the Airbag Control Unit (ACU) from establishing a normal monitoring circuit. This safety-critical fault prevents the airbag from deploying during a collision, continuously illuminates the instrument panel SRS warning lamp, and may force the entire airbag system into fail-safe mode.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 Qin Plus →Qin Plus 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.