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P25C600

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

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 — Qin Plus
  • 1Chassis scraping or vibration wear damages the insulation of the BLM temperature signal wire between the IPB and the body wiring harness, causing a short to body metal.
  • 2Insulation failure of the IPB assembly internal temperature sensor, or a cold solder joint on the PCB, causing the signal line 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, sharp edges cut the improperly secured wiring harness, or incorrect routing pinches the harness, causing a short circuit.
  • 5The NTC resistor package inside the temperature sensor failed, 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 is on, and record environmental data such as vehicle speed and temperature at the time of the fault.
  • 2
    Raise the vehicle. 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 wiring grommet, the area around the front compartment fuse box, and the harness inside the underbody protective panel. Focus on interference points with the exhaust pipe and brackets. Repair any damaged wiring harness (wrap with electrical tape or replace the harness section). Ensure sufficient clearance between the 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 internal IPB temperature sensor resistance (NTC resistance at room temperature is approximately 10 kΩ-20 kΩ). If abnormal, replace the IPB assembly.
  • 6
    After repair, reconnect all connectors. Use the diagnostic tool to clear the fault codes. Perform 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.

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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

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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 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.