AU
C002400

DTC C002400 indicates the IPB (Integrated Electro-Hydraulic Braking) system detects an electrical fault in the brake pedal pressure feedback signal circuit — Atto 3

Braking System

DTC C002400 indicates the IPB (Integrated Electro-Hydraulic Braking) system detects an electrical fault in the brake pedal pressure feedback signal circuit.

The IPB system uses the brake pedal travel sensor (or pressure sensor) to monitor the driver's braking intent in real time.

This sensor typically mounts on the brake pedal mechanism or master cylinder input and provides an analog voltage or PWM signal to the IPB ECU.

The ECU triggers this DTC when it detects an open circuit, a short to ground or power in the signal circuit, a signal voltage outside the calibrated range (e.g., 0.5-4.5V), or an abnormal signal drift rate.

This fault limits or disables the brake assist function, deactivates the ESC/ABS system, and disables the Automatic Emergency Braking (AEB) function.

The vehicle may enter mechanical backup braking mode, which significantly increases pedal effort and severely compromises driving safety.

5
Cases Logged
5
Causes
Likely Causes — Atto 3
  • 1Brake pedal travel/pressure sensor internal coil open circuit, Hall element failure, or signal drift
  • 2Sensor wiring harness worn, open, or shorted to ground at the pedal mechanism, firewall grommet, or high-temperature areas of the motor compartment.
  • 3Fault in the internal signal acquisition circuit, ADC conversion circuit, or power supply circuit of the IPB electro-hydraulic module.
  • 4Sensor connector water ingress and oxidation, terminal pin back-out, or poor contact (common after water fording or car washing)
  • 5Mechanical binding or poor return of the brake pedal mechanism applies abnormal force to the sensor or forces it beyond its operating range.
What To Do
  • 1
    Use the BYD VDS or Launch X-431 diagnostic tool to read the fault code. Confirm whether C002400 is a current (active) or history fault, and record the pedal signal voltage value from the freeze frame data.
  • 2
    Visually inspect the brake pedal mechanism for smooth movement. Inspect the sensor body and wiring harness for damage or crush marks, focusing on the wiring harness sleeve between the pedal arm and the firewall.
  • 3
    Disconnect the sensor and IPB module connectors. Use a multimeter to measure circuit continuity (Sensor-IPB), insulation resistance to ground, and short to power. Standard resistance must be less than 1 Ω, and insulation resistance must be greater than 10 MΩ.
  • 4
    Connect the plug and measure the sensor supply voltage (typically 5V±0.25V or 12V). Simultaneously measure the signal output voltage. It must change linearly with pedal travel (0.5-4.5V range) without jumps or dead zones.
  • 5
    Check the pedal signal pins in the IPB module 32-pin or 48-pin connector for back-out, oxidation, or deformation. Repair using a special tool if necessary.
  • 6
    If wiring measurements are normal but the fault persists, replace the brake pedal travel/pressure sensor (on some models, replace it together with the pedal mechanism assembly). After replacement, perform the brake pedal zero-point calibration.
  • 7
    If replacing the sensor does not resolve the fault, diagnose an internal fault in the IPB assembly. Replace the IPB electro-hydraulic module, then perform brake system bleeding, pedal calibration, and an ESC function test.
Real-World Cases
BYD DTC AI Analysis

Song PLUS DM-i pedal sensor wiring harness fatigue fracture

✓
At 80,000 km, the ABS/ESC warning lights illuminated intermittently with DTC C002400, often triggered on rough roads. Inspection found the wiring harness between the brake pedal and firewall had partially fractured internal copper strands from prolonged flexing during pedal operation, interrupting the signal. Replaced the pedal sensor with harness assembly, rerouted the wiring, and added securing cable ties to eliminate harness strain during pedal movement. Fault eliminated.
BYD DTC AI Analysis

Han EV IPB module internal signal acquisition circuit damaged

✓
Vehicle would not enter READY mode; the instrument cluster showed “Brake System Fault.” DTC C002400 was present and would not clear. Brake pedal sensor supply voltage measured 5 V (normal). Signal line voltage stayed at 0 V regardless of pedal position. Disconnected the sensor and measured signal line resistance to ground—normal, ruling out a short to ground. Internal signal acquisition circuit in the IPB module failed. Replaced the IPB assembly, filled brake fluid, bled the system, and calibrated the pedal zero-point. Fault cleared.
BYD DTC AI Analysis

Qin PLUS DM-i sensor connector oxidised due to water ingress

✓
After fording water approximately 30 cm deep, the instrument cluster brake system warning light stayed on constantly. The brake pedal felt normal, but AEB failed. Read DTC C002400. Found noticeable water inside the IPB-to-pedal sensor connector beneath the left front A-pillar; copper pins were oxidized and blackened. Cleaned the connector thoroughly with electronic cleaner, applied conductive grease, and dried it. Reconnected the connector, cleared the fault code, and restored system function.
BYD DTC AI Analysis

Tang DM-i pedal mechanism sticking caused sensor out-of-range

✓
Owner reported slow brake pedal return and intermittent 'Check brake system' warnings when parking, DTC C002400. Found the brake pedal pivot lacked lubrication and had severe dust buildup, causing the return spring to bind; the sensor detected abnormal pressure hold times and signal curves. Thoroughly cleaned the pedal mechanism, applied low-temperature grease, replaced the pedal pressure sensor that was internally damaged from long-term overload, and performed calibration. The fault did not recur.
BYD DTC AI Analysis

Voltage drop in power supply circuit causes abnormal signal — BYD Song Pro EV

✓
Instrument cluster showed intermittent brake system warning light with DTC C002400. Scan tool indicated pedal signal voltage occasionally dropped below 0.8V (normal idle ~1.2V). Sensor supply voltage measured at only 3.2V (spec 5V). Traced to poor contact at IPB module power output terminal causing voltage drop. Repaired IPB connector power pins, restoring stable 5V reference output. Fault resolved.
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.