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 — Atto 3

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.

3
Cases Logged
5
Causes
Likely Causes — Atto 3
  • 1Wheel speed sensor 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: Sensor connector pin oxidation or back-out, or damaged wiring harness shielding causing electromagnetic interference and distorting the signal during transmission.
  • 3Mechanical installation issue: Air gap between the sensor and magnetic encoder ring (tone ring) falls outside 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 required by the vehicle VIN (e.g., different output pulse count), causing the IPB to detect a protocol error.
  • 5IPB control unit internal fault: Abnormal sampling resistor or filter capacitor in the control unit input circuit causes misinterpretation of normal signals (uncommon).
What To Do
  • 1
    Initial diagnostic scan: Use VDS or a dedicated diagnostic tool to read the complete fault codes and freeze frame data. Verify if C055800 is a current fault. Record environmental parameters, such as vehicle speed and temperature, when the fault occurred.
  • 2
    Visual and connection inspection: Inspect the right rear wheel speed sensor connector (usually located near the rear suspension) for looseness, water ingress, or oxidation; inspect the wiring harness sleeve for damage, paying special attention to wear-prone areas under the chassis; inspect the magnetic encoder ring for cracks, deformation, or attached 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. Use an oscilloscope to monitor the sensor output waveform 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 specific values). Inspect the encoder ring for excessive radial runout.
  • 5
    Component replacement and matching: If the sensor is faulty, replace it with a genuine part (verify the part number matches the VIN). Install the new sensor and tighten to the specified torque (typically 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 signal jumps. Confirm the fault light does not illuminate.
Real-World Cases
BYD DTC AI Analysis

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

✓
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

✓
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

✓
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 Atto 3 Fault Codes
P0A0DBattery Energy Control Module Requested MIL IlluminationP0AA6Hybrid Battery Voltage System Isolation FaultP1A00Drive Motor "A" Performance — BYD proprietaryB1108For 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.
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.