AU
P25C600

DTC P25C600 indicates a short to ground in the BLM (Brake Load Module) temperature sensor signal wire inside the IPB (Integrated Power Brake) — Atto 3

Braking System

DTC P25C600 indicates a short to ground in the BLM (Brake Load Module) temperature sensor signal wire inside the IPB (Integrated Power Brake).

In the BYD Song PLUS DM-i One-Box braking system, the BLM typically refers to the brake motor or brake fluid temperature monitoring unit.

When the ECU detects the temperature signal voltage remaining below the set threshold (near 0V), it identifies a signal wire short to vehicle ground.

This fault prevents the IPB from accurately monitoring key component temperatures.

To prevent system overheating or degraded braking performance, the ECU triggers a safety protection mode, disables or limits electro-hydraulic brake assist, and illuminates the ABS, ESC, and brake system warning lamps.

Because this fault affects a core braking safety function, the system classifies it as a Level 3 severe fault.

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Cases Logged
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Causes
Likely Causes — Atto 3
  • 1Chassis scraping or vibration wear damages the insulation on the BLM temperature signal wire (from the IPB to the body wiring harness), causing a short to body metal.
  • 2Insulation failure of the internal temperature sensor in the IPB assembly, or a cold solder joint on the PCB causing the signal wire to short to housing ground.
  • 3Water ingress or oxidation in engine compartment or chassis connectors (such as the BJG02 or IPB 32-pin connector) causing a short to ground between pins.
  • 4During accident repairs or chassis maintenance, improper securing allows sharp edges to cut the wiring harness, or incorrect refitting pinches the harness and causes a short circuit.
  • 5Internal NTC resistor package failure within the temperature sensor body, shorting the signal terminal to the sensor housing.
What To Do
  • 1
    Connect the VDS2000/VDS3000 diagnostic tool, read all fault codes and freeze frame data, confirm P25C600 is a current fault and the IPB-related warning lamp illuminates, and record environmental data such as vehicle speed and temperature at the time of the fault.
  • 2
    Raise the vehicle and visually inspect the IPB assembly (located on the left side of the front compartment firewall) and the wiring harness. Inspect areas where the harness contacts sharp body edges and check for loose retaining clips. Check for obvious damage, water ingress, or burn marks.
  • 3
    Disconnect the IPB assembly 32-pin main connector and the BLM temperature sensor connector (if detachable separately). Use a multimeter to measure the resistance between the signal wire (refer to the circuit diagram for the specific pin) and body ground: if the resistance is less than 5 Ω, this confirms a short to ground in the wiring harness; if the resistance is infinite, the fault is inside the IPB.
  • 4
    Inspect the wiring harness in sections along its routing: check the firewall grommet, the area near the front compartment fuse box, and the harness inside the underbody shield. Focus on interference points with the exhaust pipe and brackets. Repair damaged wiring (wrap with insulating tape or replace the harness section). Ensure sufficient clearance between the wiring harness and the vehicle body.
  • 5
    If wiring harness measurements are normal, inspect the connector terminals for push-out, corrosion, or conductive debris. Clean or replace the connector. If the connector is normal, measure the IPB internal temperature sensor resistance (NTC resistance is approximately 10kΩ-20kΩ at room temperature). If abnormal, replace the IPB assembly.
  • 6
    After repair, reconnect all connectors. Use the diagnostic tool to clear the fault codes. Execute the IPB system bleeding and calibration procedure (Brake System Bleeding & Calibration). Turn IGN ON and perform a self-check to confirm no fault codes are present. Road test the vehicle to verify normal ABS/ESC function and that the warning lamp is off.
Real-World Cases
BYD DTC AI Analysis

Incorrectly installed underbody shield caused wiring harness chafing and short circuit

✓
A 2021 Song PLUS DM-i with 30,000 km on the clock displayed a sudden "Braking System Fault" warning after the owner drove through water. Scanned DTCs P25C600 and C003F00. Raised the vehicle and found the IPB wiring harness clip below the right front wheel arch liner had detached, allowing the loom to chafe against a sharp edge on the chassis subframe until the insulation wore through. Water from the wading conducted current, shorting the BLM signal wire to ground. Repair: Cut out the damaged section and reconnected the harness with heat-shrink tubing, resecured the wiring to specification with additional corrugated tubing protection, and adjusted the underbody shield position to prevent pinching. Cleared the DTCs and all functions returned to normal.
BYD DTC AI Analysis

IPB internal temperature sensor failure

✓
2022 Song Pro DMi, no accident history. ESC warning light came on intermittently; scanner showed P25C600 history fault. External wiring harness checked multiple times — no damage. IPB connector terminal insulation to ground measured normal. Disassembled IPB assembly for further inspection (requires specialized equipment). Found internal BLM temperature monitoring module NTC resistor encapsulation cracked, pins contacting housing. IPB is a sealed safety-critical assembly, so replaced with new IPB electro-hydraulic module (part number HA2E-3555100). Performed system bleeding and online matching. Fault eliminated.
BYD DTC AI Analysis

Water entered the connector after accident repairs, causing a short circuit.

✓
One week after front collision repairs, a Song PLUS DMi displayed a brake system warning. The 32-pin IPB connector in the front compartment was not fully latched and had obvious water stains inside from washing. The BLM temperature signal pin (typically pin X) shorted to the adjacent ground pin due to conductive water film. Technicians thoroughly blow-dried the connector, cleaned terminal oxides with electronic cleaner, applied conductive protectant, properly reconnected it, and confirmed the latch locked. The fault cleared and did not recur over one month of follow-up.
BYD DTC AI Analysis

Aftermarket underbody protection installation pinched the wiring harness, causing a short circuit

✓
The owner took the vehicle to a non-authorized workshop for underbody coating without adequately masking the IPB wiring harness. The coating seeped into the harness corrugated tubing and cured, causing the wiring to harden and become brittle. Driving vibrations broke the hardened harness at the mounting bracket, exposing the BLM signal wire core which contacted the vehicle body. Technicians removed the foreign coating material, replaced the damaged harness section, rerouted the wiring and added rubber protective sleeves. They emphasized that modification work must follow BYD technical specifications.
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.