AU
C001500

DTC C001500 indicates the IPB (Integrated Power Brake) ECU detects a circuit fault while actuating the right front wheel outlet valve (RF Outlet Valve, a Normally Closed Valve) — Seal 6 EV

Braking System

DTC C001500 indicates the IPB (Integrated Power Brake) ECU detects a circuit fault while actuating the right front wheel outlet valve (RF Outlet Valve, a Normally Closed Valve).

This solenoid valve returns brake fluid from the right front wheel cylinder to the reservoir or master cylinder during the ABS/ESC pressure release phase, enabling precise brake force control.

Root causes include an open or short circuit in the solenoid coil, a damaged ECU on-board driver chip (MOSFET/ASIC), abnormal current feedback (e.g., mechanical valve sticking causing a current over-limit), or a wiring harness fault.

This fault prevents the right front wheel from achieving accurate pressure build-up, hold, and release cycles, and disables ABS/ESC functions.

In extreme cases, it causes right front wheel brake drag and uneven brake force distribution, severely compromising driving safety.

3
Cases Logged
5
Causes
Likely Causes — Seal 6 EV
  • 1Open circuit, inter-turn short circuit, or short to housing in the right front outlet valve solenoid coil inside the IPB assembly.
  • 2Damaged onboard solenoid valve drive circuit in the IPB control unit (ECU) (e.g., L9305 chip failure or high-side/low-side driver transistor breakdown)
  • 3IPB wiring harness connector (usually a 32-pin or 48-pin plug): oxidation, terminal back-out, water ingress corrosion, or poor contact at the corresponding pins.
  • 4Severe brake fluid contamination (excessive water content or impurities) causes the solenoid valve spool to stick, resulting in drive current exceeding the calibrated threshold.
  • 5IPB power supply system fault (battery voltage below 9V or above 16V, or excessive ground resistance) causes false protection of the drive circuit.
What To Do
  • 1
    Diagnostic tool readout: Use a BYD VDS or Launch X-431 diagnostic tool to read complete DTCs, freeze frame data, and the Fault Occurrence Counter (FDC). Record key data at the time of the fault, such as vehicle speed, wheel speed, and brake pedal travel.
  • 2
    Visual inspection: Inspect the IPB assembly (located on the left side of the front bulkhead in the engine compartment) for impact deformation or brake fluid leaks. Carefully inspect wiring harness connectors X1 and X2 for looseness, failed locking tabs, damaged sealing rings, or water stains/corrosion.
  • 3
    Solenoid valve resistance measurement: Disconnect the IPB connector. Use a multimeter to measure the resistance between the two terminals of the right front outlet valve solenoid (standard value: approximately 2.0-10.0Ω at 20°C; refer to the vehicle repair manual for specific values). If the resistance is infinite (open circuit) or close to 0Ω (short circuit), the internal coil is faulty.
  • 4
    Wiring harness continuity test: Measure circuit continuity from the valve body side pin of the IPB connector to the corresponding ECU side pin. Check for open circuits, shorts to power, or shorts to ground. Measure the circuit insulation resistance; it must be greater than 10MΩ.
  • 5
    Power supply and ground check: Use an oscilloscope or multimeter to measure the voltage at the IPB power supply pins (constant power B+, ignition power IG1) and the voltage drop at the ground pins. Ensure the voltage is within the 12-14V range while the engine is running, and the ground voltage drop is less than 0.1V.
  • 6
    Actuation test verification: Connect the diagnostic tool and perform the "solenoid valve actuation test" or "hydraulic unit function test". Listen for a crisp "click" from the right front outlet valve. If there is no sound or the diagnostic tool reports a drive failure, this indicates a mechanically stuck valve body or an ECU drive circuit fault.
  • 7
    Component replacement: After confirming the fault, replace the IPB electro-hydraulic module assembly (Song PLUS DM-i spare part number example: 6A-3505010-XX). Recover brake fluid from the old module before replacement to prevent contamination.
  • 8
    System calibration and bleeding: After replacement, use the diagnostic tool to perform the "Brake Line Automatic Bleeding" procedure (requires continuously pumping the brake pedal), then perform "ESC Sensor Calibration", "Longitudinal Acceleration Sensor Calibration", and "Steering Angle Sensor Calibration".
  • 9
    Road test verification: Clear all fault codes. Perform a static brake pedal test. Confirm no leakage, then perform emergency braking tests at low speed (20km/h) and high speed (above 60km/h). Verify the ABS operates normally, there is no abnormal brake drag, and the fault code does not recur.
Real-World Cases
BYD DTC AI Analysis

BYD Song PLUS DM-i ABS/ESP warning, right front outlet valve driver circuit fault

✓
While driving, the ABS and ESC warning lights came on. Scanned DTC C001500 (Right Front Outlet Valve Drive Fault). Checked IPB wiring harness connections; normal. Measured internal solenoid resistance; open circuit. Confirmed open circuit in right front normally closed valve coil inside IPB assembly. Replaced IPB electro-hydraulic module assembly. Performed sensor calibration. System returned to normal.
Original source ↗
BYD DTC AI Analysis

Dashboard ABS warning light stays on. Diagnosis: right front outlet valve circuit fault.

✓
After starting the vehicle, the ABS warning light remained illuminated and the system failed its self-test. The scan tool retrieved DTC C0015 (right front outlet valve fault). Inspection revealed an internal circuit fault in the right front outlet valve within the ABS Hydraulic Control Unit (HCU); the solenoid valve would not actuate. The external wiring harness showed no damage, confirming an internal HCU failure. Replacing the ABS Hydraulic Control Unit assembly resolved the fault.
Original source ↗
BYD DTC AI Analysis

ESC warning light illuminated while driving; faulty normally closed valve in right front wheel caused abnormal braking.

✓
While driving, the ABS and ESC warning lights suddenly illuminated and the driver felt abnormal brake pedal travel. The scan tool displayed C0015-00 (right front normally closed valve fault). Testing revealed the right front outlet valve resistance fell outside the standard range (2-10 ohms) and the valve produced no operating sound during the actuator test. Confirmed an internal IPB solenoid valve fault. Replaced the IPB assembly, bled the brakes and calibrated the ESC. The fault codes cleared and the road test returned normal results.
Original source ↗
Other Seal 6 EV 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.B1737DTC B1737 indicates the Supplemental Restraint System (SRS) detected abnormal continuity between the right middle-row side airbag squib circuit (typically the second-row right seat side airbag or right curtain airbag) and the vehicle power supply (B+, battery positive). The SRS ECU monitors the airbag inflator resistance via an internal current source (normal resistance: 2.0–3.0 Ω). If the ECU detects the voltage across the inflator circuit remaining close to battery voltage (>5 V and approaching 12 V) instead of the expected low potential or floating state, it identifies a short to power. This fault prevents the airbag from deploying normally during a collision because the short circuit bypasses the firing current. In extreme cases, abnormal current can cause unintended deployment, posing a severe safety hazard.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 Seal 6 EV →Seal 6 EV 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.