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 U

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 U
  • 1Open circuit, inter-turn short circuit, or short to housing in the right front outlet valve solenoid coil inside the IPB assembly
  • 2Damaged IPB control unit (ECU) onboard solenoid valve drive circuit (e.g., breakdown of the L9305 chip or high-side/low-side driver transistors)
  • 3Oxidation, backed-out terminals, corrosion from water ingress, or poor contact at the corresponding pins of the IPB wiring harness connector (usually a 32-pin or 48-pin plug)
  • 4Severe brake fluid contamination (excessive water content or impurities) causes the solenoid valve spool to stick, resulting in the drive current exceeding the calibrated threshold.
  • 5IPB power supply system fault (battery voltage below 9V or above 16V, or excessive ground resistance) causing false protection of the drive circuit.
What To Do
  • 1
    Diagnostic scan: Use the BYD VDS or Launch X-431 diagnostic tool to read the complete DTCs, freeze frame data, and Fault Detection 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 engine compartment bulkhead) for impact deformation or brake fluid leakage. Specifically check 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 exact specifications). If the resistance is infinite (open circuit) or near 0Ω (short circuit), the internal coil is faulty.
  • 4
    Harness continuity test: Measure continuity between the valve body side pin of the IPB connector and the corresponding ECU side pin. Check for an open circuit, short to power, or short 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 B+, ignition IG1) and the voltage drop at the ground pins. With the engine running, verify the voltage is 12-14V 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 clear "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 example part number: 6A-3505010-XX). Before replacement, recover the brake fluid from the old module to prevent contamination.
  • 8
    System calibration and bleeding: After replacement, use the diagnostic tool to execute 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. After confirming no leakage, perform emergency braking tests at low speed (20 km/h) and high speed (above 60 km/h) to verify the ABS operates normally, no abnormal brake drag occurs, 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 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.