AU
C053E00

DTC C053E00 indicates a short to ground in the signal circuit of IPB (Intelligent Integrated Braking System) master cylinder pressure sensor 1 — Qin Plus

Braking System

DTC C053E00 indicates a short to ground in the signal circuit of IPB (Intelligent Integrated Braking System) master cylinder pressure sensor 1.

This sensor monitors brake master cylinder hydraulic pressure in real time and serves as the core feedback component of the brake-by-wire system.

The ECU uses this signal to calculate brake assist demand, trigger energy recovery, and control ABS/ESC intervention timing.

The ECU sets this fault when it detects the sensor signal voltage remaining continuously below the threshold (typically <0.5 V, normal range 0.5–4.5 V) or an abnormal drop in signal wire resistance to ground.

This fault causes abnormal brake pedal feel (too hard or too soft), degrades energy recovery, and forces the ESC/ABS system into a degraded mode (illuminating multiple instrument cluster warning lights).

Extreme cases may trigger limp-home mode (speed-limited driving).

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Cases Logged
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Causes
Likely Causes — Qin Plus
  • 1Physical damage to the wiring harness: Worn or age-cracked harness sheathing near high-temperature areas in the engine compartment or steering mechanism causes the signal wire (usually a 0.5-1.0 mm² wire) to short circuit against metal body parts.
  • 2Connector water ingress and corrosion: Seal failure on the IPB assembly 24-pin main connector or sensor sub-connector. Driving through water or high-pressure washing oxidizes the internal terminals, creating a low-resistance path between the signal terminal (pin) and the ground terminal.
  • 3Sensor body internal short circuit: Damage to the pressure-sensitive element or signal conditioning circuit inside the master cylinder pressure sensor causes the output terminal to short to the housing/ground wire (internal insulation breakdown).
  • 4IPB controller internal fault: RC filter capacitor breakdown or ESD protection diode short circuit in the control unit's internal signal sampling circuit causes the system to falsely detect an external circuit short to ground.
  • 5Improper repair: Improperly securing the wiring harness during accident repair or modification allows metal edges to pinch the harness, or loose insulation tape causes abrasion damage.
What To Do
  • 1
    Initial diagnosis: Use VDS2000/VDI to read the complete fault codes and check for accompanying codes C053D00 (pressure out of range) or C053F00 (circuit open). Record freeze frame data (vehicle speed, brake pedal travel, and pressure value at the time of the fault).
  • 2
    Visual inspection: Focus on the transition area between the IPB assembly (located on the left side of the engine compartment firewall) and the body wiring harness. Check the 24-pin grey connector for water ingress (inspect terminals for green corrosion). Inspect the wiring harness for abrasion where it passes through the firewall grommet.
  • 3
    Circuit measurement: Disconnect the IPB connector. Use a multimeter to measure the resistance between the signal wire (usually Pin 15, or refer to the specific pinout diagram) and ground. Normal resistance is >10MΩ. A reading <10Ω confirms a short circuit. Measure in sections to locate the short (disconnect intermediate connectors and troubleshoot section by section).
  • 4
    Sensor body test: Disconnect the pressure sensor connector. Measure the resistance between the signal terminal and ground terminal on the sensor side. If the resistance is <100Ω, replace the sensor. Measure the signal wire resistance to ground on the wiring harness side to confirm the short circuit is in the wiring harness, not the sensor.
  • 5
    Insulation repair: Upon finding wiring harness damage, strip back the damaged section and re-insulate using heat-shrink tubing or waterproof tape. Adjust the wiring harness routing to avoid contact with sharp edges. If water has entered the connector, clean using electrical contact cleaner and spray WD-40 water repellent. Replace the connector terminals if necessary.
  • 6
    Function check: After repair, clear the fault code. Run the IPB system bleeding procedure (use the diagnostic tool to activate the motor pump). Perform a brake pedal feel test and a road test. Confirm the pressure sensor signal changes linearly within the 0-16 MPa range without jumps or signal loss.
Real-World Cases
BYD DTC AI Analysis

Song Plus DM-i multiple system warnings after water ingress (C053E00+C053F00)

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A 2021 Song PLUS DM-i displayed simultaneous ABS, ESP and brake system warning lights after driving through standing water during heavy rain. Fault codes: C053E00 (Pressure Sensor 1 short to ground) and C053F00 (circuit open). Inspection revealed water inside the 24-pin connector below the IPB assembly. Electrolyte contamination had shorted Pin 15 (pressure sensor signal) to Pin 7 (ground). Repair: Removed the connector, cleaned the terminals with anhydrous ethanol, dried them with compressed air, applied conductive grease and reinstalled. A degraded connector seal caused the water ingress. Replaced the seal and cleared the fault. Total repair time: 2.5 hours.
BYD DTC AI Analysis

Wiring harness pinched during accident repair, causing intermittent short circuit

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Following front-end collision repairs, the vehicle developed intermittent brake pedal stiffness while driving and the ESC warning lamp illuminated. The diagnostic scanner showed history DTC C053E00. Inspection revealed that when securing the bulkhead harness, the repairer had clamped the IPB pressure sensor wiring against the edge of a metal bracket. Driving vibrations wore through the insulation, causing intermittent shorting between the signal wire and the bracket. Technicians rerouted the harness, wrapped the damaged section with foam tape, and repositioned the cable ties to eliminate stress concentration. This completely resolved the fault.
BYD DTC AI Analysis

IPB internal circuit failure caused false fault codes (sensor normal)

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2022 Song Pro DM-i repeatedly set C053E00. Replaced the pressure sensor and wiring harness, but the fault persisted. Disconnected the sensor and measured resistance from the IPB controller's internal signal sampling terminal to ground: only 50Ω. This confirms the filter capacitor in the controller's internal signal processing circuit has shorted. Replaced the IPB assembly (part number SC-3645100), completed system configuration and brake bleeding, and the fault cleared. Isolated IPB controller hardware defect; process as warranty claim.
BYD DTC AI Analysis

Water entered sensor connector, causing short circuit after high-pressure wash.

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After the owner used a high-pressure washer to clean the engine bay, the vehicle reported a brake system fault on startup (code C053E00). Inspection revealed the waterproof cover on the pressure sensor connector (located on top of the brake master cylinder) was not fully seated, allowing water to enter and short the signal terminals to ground. Repair: Disconnected the connector and allowed it to dry, cleaned it with precision electronics cleaner, measured insulation resistance until it returned to normal, then reset. Advised the owner to avoid directing high-pressure water at electrical components.
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.