AU
C059592

The IPB (Intelligent Power Brake) system triggers this DTC when the internal power drive circuit of the Electrical Booster detects an abnormal power supply — Qin Plus

Braking System

The IPB (Intelligent Power Brake) system triggers this DTC when the internal power drive circuit of the Electrical Booster detects an abnormal power supply.

The IPB system integrates the conventional vacuum booster, ABS, ESP, and EPB into a single unit, and uses a motor-driven hydraulic system to generate brake assist.

DTC C059592 indicates the control module detects the booster motor supply voltage falls outside the normal threshold (typically 9-16V), or the internal DC-DC conversion circuit, power drive MOSFET, or power management chip operates abnormally.

This fault disables or limits the electric brake assist function and significantly stiffens the brake pedal (requiring over 200N of pedal force).

Simultaneously, the system triggers safety protection mechanisms, restricting ADAS functions such as Autonomous Emergency Braking (AEB) and Adaptive Cruise Control (ACC), severely compromising driving safety.

The C059592 fault code on the Qin Plus indicates an abnormal power supply in the IPB electric brake booster’s internal power drive circuit. Severity is medium, but brake assist may be limited, making the pedal much harder and reducing ADAS functions like AEB or ACC. Common causes include a weak 12V battery/charging fault or poor IPB power or ground connections. Visit an authorised dealer for diagnosis and repair. Typical repair cost data is available.
5
Cases Logged
5
Causes
Likely Causes — Qin Plus
  • 1Low-voltage power supply system fault: Increased internal resistance due to battery aging, insufficient alternator charging, or a voltage regulator fault causes voltage to drop below 9V during starting or high-current conditions.
  • 2Wiring connection fault: Poor contact at the fuse in the IPB power supply circuit (usually 30A or 40A), loose power connector, oxidized or backed-out terminals, or loose ground points G06/G08 causing excessive circuit resistance.
  • 3IPB internal power supply module fault: damaged internal DC-DC converter, short/open circuit in the power assist motor drive circuit, overheating damage to power components on the PCB.
  • 4Brake booster motor internal fault: A short or open circuit in the motor winding causes abnormal current, triggering power supply protection.
  • 5Environmental factors: Poor heat dissipation at the IPB mounting location triggers thermal protection, or connector seal failure allows water ingress, causing internal circuit corrosion and short circuits.
What To Do
  • 1
    Use the VDS2000/VDS3000 diagnostic tool to read the complete fault codes and freeze frame data. Record key parameters at the time of the fault, such as vehicle speed, voltage, and pedal position. Check for accompanying fault codes such as C059500 and C058200.
  • 2
    Check the vehicle low-voltage power supply system: measure the battery static voltage (should be ≥12.4V), cranking voltage (should be ≥9.6V), and charging voltage (should be 13.8-14.8V). Check the battery internal resistance and State of Health (SOH).
  • 3
    Check the IPB power supply circuit: Check the IPB power supply fuse (usually F1/30A or F2/40A) and relay in the engine compartment fuse box. Measure the voltage at terminals B01-1 (+BAT constant power) and B01-2 (+IG1 ignition power) of the IPB connector. Check the tightness of ground points G06 and G08, and measure the ground resistance (should be <1Ω).
  • 4
    Dynamic voltage test: Measure voltage fluctuation at the IPB connector during vehicle startup and power assist motor operation. Verify no instantaneous voltage drop or spike.
  • 5
    Check the IPB physical condition: Verify the IPB mounting bracket is secure, heat dissipation is adequate, the connector shows no signs of water ingress or corrosion, and the sealing ring is intact.
  • 6
    Perform system bleeding: If the vehicle has a history of brake fluid replacement or line disconnection, run the IPB electric bleeding procedure to eliminate motor overload caused by air lock.
  • 7
    Software flash and calibration: Flash the IPB control program to the latest version. If the fault persists, replace the IPB assembly.
  • 8
    Calibration after replacement: After replacing the IPB, perform yaw rate sensor calibration, brake pedal position sensor zero-point learning, linear valve learning, and the brake line bleeding procedure.
Real-World Cases
BYD DTC AI Analysis

Loose power supply connection caused power assist failure in Seal 06 DM-i

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Dashboard showed brake system fault, ESP warning light illuminated, and brake pedal became hard. Scan tool read IPB system DTC C059592 (Electrical booster power supply abnormal). Found loose connection in IPB power supply fuse holder; voltage dropped to 8.2V under high current. Repaired fuse holder terminals and tightened power wiring harness connectors to clear the fault. One week later the fault returned. Further testing found intermittent open circuit in IPB internal power module. Replaced IPB assembly and performed calibration to resolve.
Original source ↗
BYD DTC AI Analysis

Excessive battery voltage drop during cold start triggered Han EV fault

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The owner reported occasional heavy brake pedal on cold starts, with the instrument cluster displaying "Check Brake System". The fault cleared after warmup. Retrieved historical DTC C059592. Testing revealed battery degradation (internal resistance 18mΩ, state of health 62%). Voltage dropped to 8.5V at startup, causing insufficient power to the IPB assist motor and triggering protection. Replaced the battery and tightened the IPB ground lead. Monitored cold starts for one week with no recurrence.
Original source ↗
BYD DTC AI Analysis

Song PLUS DM-i IPB poor heat dissipation causing intermittent fault

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While driving, the instrument cluster suddenly displayed a brake system fault. The ABS and ESP warning lights illuminated and brake pedal travel increased. Scanning revealed codes C059592 and C058200 (abnormal motor circuit signal). The fault occurred intermittently, returning after 50-100 km once cleared. Inspection showed the IPB mounted close to the turbocharger; a missing heat shield caused internal overheating of the control unit, activating thermal protection in the power module. Reinstalled the heat shield, cleaned the IPB connector and applied conductive grease. The fault has not recurred.
Original source ↗
BYD DTC AI Analysis

Qin PLUS DM-i brake booster motor internal short circuit

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The brake pedal gradually hardened until almost no assist remained, with the instrument panel showing continuous warnings. Retrieved DTC C059592. Measured IPB supply voltage at 12.8V (normal), but the scan tool showed abnormal booster motor current: peak exceeded 30A then suddenly dropped to zero. Disassembled the IPB and found partial short circuit in the brake booster motor windings, triggering internal drive circuit overload protection. Replaced the IPB integrated brake unit assembly, calibrated the yaw rate sensor, bled the brakes, and cleared the fault.
Original source ↗
BYD DTC AI Analysis

Water ingress corroded the Dolphin's IPB connector, causing abnormal power supply.

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Brake system fault after vehicle drove through water; dashboard displayed "Service Brake System". Found IPB connector seal damaged with water inside and green corrosion on pins. Cleaned and dried connector; fault temporarily cleared but returned after two days. Measured power pin contact resistance at 3.2Ω (normal <0.5Ω), causing voltage drop to booster motor under load. Replaced IPB wiring harness connector, cleaned ground point, and replaced IPB assembly (internal circuit corrosion). Fault fully resolved.
Original source ↗
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.