AU
C054300

DTC C054300 indicates an abnormal electrical signal from Pressure Sensor 2 in the IPB (Intelligent Power Brake) electro-hydraulic module, specifically a short to power, short to ground, or open circuit in the signal circuit — Seal U

Braking System

DTC C054300 indicates an abnormal electrical signal from Pressure Sensor 2 in the IPB (Intelligent Power Brake) electro-hydraulic module, specifically a short to power, short to ground, or open circuit in the signal circuit.

This sensor monitors brake master cylinder pressure (or wheel cylinder pressure channel 2) and provides a key input signal for ESC (Electronic Stability Control) and brake assist functions.

The ECU logs a hardware-level fault when it detects the sensor voltage signal falling outside the calibrated range (typically below 0.3V or above 4.7V, depending on the 5V reference voltage division logic).

This fault forces the IPB into a degraded mode, disabling ESC/ESP and Automatic Emergency Braking (AEB) functions.

The system may trigger limp mode (reducing brake assist).

In extreme cases, the brake pedal hardens or braking distance increases, posing a serious safety hazard.

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Cases Logged
5
Causes
Likely Causes — Seal U
  • 1Internal open or short circuit in the pressure sensor: damage to the pressure-sensitive element or internal conditioning circuit causes an abnormal output signal.
  • 2Poor wiring harness connector contact: Pin back-out, oxidation, or corrosion from water ingress at the 32-pin (or 24-pin) connector on the IPB electro-hydraulic module, causing an intermittent or continuous open circuit.
  • 3Wiring harness wear and short circuit: Sensor wiring harness insulation degrades in the high-temperature engine compartment and rubs against metal body edges, causing a short to ground or short to power.
  • 4IPB ECU internal sampling circuit fault: Damaged ECU analog-to-digital converter (ADC) channel or reference voltage regulator fault, preventing correct sensor signal readings.
  • 5Power supply or ground circuit fault: Blown sensor 5V reference voltage circuit fuse or loose ground terminal, causing the sensor to lose power.
What To Do
  • 1
    Diagnostic tool check: Use the BYD VDS or Bosch KTS diagnostic tool to read the complete fault codes and freeze frame data. Check for an accompanying C054200 (Pressure Sensor 1 Fault) or other IPB communication faults. Record the vehicle speed and brake pedal status at the time of the fault.
  • 2
    Visual and connector inspection: Disconnect the 12V battery negative terminal. Check the IPB electro-hydraulic module electrical connector (usually located on the left side of the firewall or at the ABS pump position). Inspect the pins for oxidation or unseating. Check the wiring harness for wear or crush marks, especially the protective sleeve near high-temperature areas in the engine compartment.
  • 3
    Static voltage measurement: Reconnect the battery and turn the ignition switch to the ON position (do not press the brake pedal). Use a multimeter to measure the voltage of the pressure sensor 2 signal wire (usually corresponding to a specific connector pin, such as pin X). Normal voltage is 2.0-2.5V (zero-pressure reference). A reading of 0V, 5V, or a floating voltage confirms a wiring fault.
  • 4
    Sensor power supply and ground check: Measure the voltage between the sensor power supply pin (5V Ref) and the ground pin to confirm the ECU provides a stable 5V reference voltage. Ground resistance must be less than 1Ω.
  • 5
    Harness continuity and insulation test: Disconnect the IPB and ECU connectors. Measure the signal harness continuity resistance (should be less than 1 Ω) and the insulation resistance to ground and power supply (should be greater than 10 MΩ). Locate any short circuits.
  • 6
    Sensor replacement verification: If the wiring harness is normal, replace the IPB electro-hydraulic module assembly (the pressure sensor is not available separately; replace the entire assembly). After replacement, perform the brake system bleeding procedure, sensor zero-point calibration, and ESC function test.
Real-World Cases
BYD DTC AI Analysis

Song PLUS DM-i — Stiff Brake Pedal with Multiple System Warnings

✓
The instrument cluster displayed 'Braking System Fault' and 'Automatic Emergency Braking Function Limited'. Fault codes: C054300 and U012100 (IPB communication fault). Inspection found the IPB electro-hydraulic module at the firewall. The wiring harness retaining clip above it had detached, allowing the harness to rub against the engine heat shield edge. This wore through the insulation on pressure sensor 2's signal wire, shorting the copper core to ground. Repaired the damaged wiring (re-wrapped and fitted with corrugated sleeving), rerouted the harness to avoid contact, cleared the fault codes and performed IPB pressure sensor calibration. Fault resolved.
BYD DTC AI Analysis

BYD Han EV: ESC warning light stays on after driving through water

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After driving through flooded roads during heavy rain, the dashboard ESC warning light illuminated. VDS detected C054300 (current fault). Inspection of the IPB electro-hydraulic module connector revealed obvious water inside. Water ingress caused electrolytic corrosion between pins A12 (pressure sensor 2 signal) and A13 (ground), increasing contact resistance (measured 5.6Ω). Repair: Thoroughly cleaned the connector with electronic contact cleaner, blow-dried it, applied conductive grease, and replaced the waterproof seal ring. Fault did not reappear.
BYD DTC AI Analysis

Tang DM-i intermittent brake boost failure

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Customer reported intermittent hard brake pedal with the warning light flickering. Scan tool showed historic fault code C054300; freeze frame data indicated brake pressure sensor 2 signal voltage was 0.02V (short to ground) when the fault occurred. Wiggling the IPB wiring harness reproduced the fault. Found pin 8 (sensor power supply) on the electro-hydraulic module connector had recessed, causing poor contact with the sensor terminal. Under vibration, this intermittently disconnected and the ECU interpreted this as a short to ground. Repair: Replaced IPB connector assembly (or repaired pin), ensuring all terminal heights are uniform. Fault resolved.
BYD DTC AI Analysis

Replaced IPB assembly on Seal, fault persists

✓
After an accident, the IPB electro-hydraulic module was replaced, but DTC C054300 would not clear. The new module carried an aftermarket part number; though externally identical, its internal pressure sensor 2 calibration parameters did not match the vehicle. Further investigation showed the technician skipped the 'post-IPB replacement online configuration' procedure, so the ECU could not recognize the new sensor's characteristic curve. Solution: Performed the 'IPB replacement' online configuration using BYD VDS, wrote the correct parameter calibration values, performed brake line bleeding and pressure sensor zero-point learning. Fault 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.