BYD Han DM-p IPB Integrated Brake System Replacement Calibration and Bleeding Guide

Fault Background

The Han DM-p uses an IPB integrated brake control system assembly to replace the traditional vacuum booster + ABS pump combination: the electronic control unit, pressure-building motor, valve block, and master cylinder are integrated into one housing, with four hydraulic circuits directly external. This structure brings two maintenance characteristics: first, before replacing parts, the assembly must first enter "installation mode"; forced disassembly will cause system degradation; second, bleeding, configuration writing, and sensor calibration are all performed via the diagnostic scan tool, not just by loosening bleed screws. This article compiles a field guide for IPB assembly fault pre-treatment, replacement and software calibration, brake bleeding, and inspection data for conventional brake components.

IPB Assembly and After-Sales Fault Pre-Treatment

When the vehicle enters the workshop, first collect and feed back four types of information to BYD after-sales: how the vehicle was operated before and after the fault occurred, whether there were text prompts or warning lights during the fault, the frequency of the fault, and whether it recovered after re-powering and restarting.

Then use VDS to diagnose with fixed steps:

1. Connect VDS to the OBD diagnostic port;
2. Vehicle power-on self-check completes;
3. Establish communication, read and store DTCs;
4. Analyze whether the DTC is a current fault or a history fault;
5. Query the "IPB DTC Analysis and Handling Measures" table according to the DTC; if not resolved, proceed to the replacement process.

Assembly handling and carrying: Carry by gripping the motor and auxiliary area, or the mounting plate and auxiliary area; the second hand may only contact the "green area" on the housing for balance. Do not carry by the mounting plate, motor, brake fluid reservoir, pushrod, or ECU port—these may cause internal damage.

IPB Assembly Replacement and Software Calibration

Replacement steps (key points):

1. Power on the vehicle, use VDS to set IPB to "installation mode", then power down the vehicle;
2. As needed, remove front compartment peripheral components: ventilation cover assembly, air filter assembly, wiper assembly, wiper motor assembly, water channel assembly, etc.;
3. Disconnect front compartment wiring harness connectors to IPB (fluid level alarm, IPB ECU);
4. Disconnect the oil pipe between IPB and remote reservoir: first extract the brake fluid from the remote brake fluid reservoir, and plug the oil pipe opening to prevent splashing;
5. Pre-remove components needed to lower the powertrain, appropriately lower the front compartment powertrain (note disconnecting connections with peripheral components to prevent damage);
6. Disconnect brake hard lines from IPB, plug the outlet ports and hard line fittings with shop towels or dust caps;
7. Remove the brake light switch, remove the four nuts connecting IPB to the brake pedal, use the brake pedal ball socket special removal tool to disconnect the brake pedal arm from IPB (prevent front compartment drop, prevent brake pedal bracket deformation);
8. Remove the IPB assembly, do not deform or damage the brake hard lines;
9. Remove the new part from the packaging (refer to handling and carrying method), parts that have fallen from a height must not be reused;
10. Replace the remote brake fluid reservoir;
11. Screw the four studs into the mounting holes, hand-tighten the mounting nuts until position is relatively stable, then use pneumatic or electric tool to tighten to 30±3N·m (IPB must not be impacted during installation, mounting pads and body mounting surface clean and free of foreign matter);
12. Lightly press the brake pedal surface to press the pushrod ball head into the pedal arm ball socket, avoid prying the pushrod from the side; after installation, pushrod angle in all directions <3°;
13. Use appropriate tools to remove the sealing plugs from the outlet ports and brake hard lines, avoid damaging threads and sealing areas;
14. Connect brake hard lines to corresponding outlet ports with specified torque—do not mix up brake hard lines, otherwise brake failure may occur (two types of line fitting torques: 18±2N·m, 20±2N·m);
15. Remove the remote brake fluid reservoir inlet plug, connect the hose to the remote reservoir and secure with clamp;
16. Connect front compartment wiring harness to IPB ECU and fluid level sensor;
17. Install peripheral components in reverse order of removal, replacement work complete;
18. Power on the vehicle, again set IPB to "installation mode";
19. Perform brake system bleeding using the dry bleeding method;
20. After bleeding, perform vehicle configuration writing and sensor calibration;
21. Re-power and start, check that all brake system warning lights on the instrument cluster are off.

Vehicle configuration writing and sensor calibration (VDS interface: select vehicle series → select vehicle model → select "electro-hydraulic brake" → execute scan → execute "vehicle configuration writing" → select "end-of-line calibration"):

• If there is a fault in the brake system before vehicle configuration writing, do not drive the vehicle; must write according to actual vehicle model and configuration.
• Internal sensor calibration conditions: vehicle supported by its own wheels, only the driver seated in the vehicle, steering wheel straight ahead and front wheels straight, normal load, normal tire pressure, fuel tank low volume allowed, no opening/closing of doors or front hood to avoid interference.
• Calibration can be performed on a roller dynamometer or flat road, maximum inclination angle ±0.5° (±1% grade), both alignment directions must be satisfied.
• If calibration fails, wait and recalibrate; after successful calibration, clear DTCs, power cycle the vehicle, check instrument cluster for brake system warnings.

Remote brake fluid reservoir replacement (aftermarket standard reservoir must be replaced with BYD remote reservoir): remove positioning screw and pull out reservoir → check that the brake fluid filter screen at the hydraulic unit interface is correctly installed (may be pulled out during removal, filter screen locating pin must insert into hydraulic unit locating blind hole) → assemble new reservoir seal ring and lubricate with brake fluid → rotate downward and press into alignment with hydraulic unit connection port → tighten positioning screw with torque wrench to 5.5±0.5N·m.

Brake System Bleeding: Wet and Dry

• Bleeding sequence: IPB has four hydraulic circuits: right front, right rear, left front, left rear; must bleed each wheel in the order specified in the manual, otherwise restart.
• Success criteria: No ABS, ESP brake system warnings on instrument cluster, no abnormal noise when pressing brake pedal, normal pedal feel; after completion, extract excess brake fluid, ensure maximum fluid level at MAX mark on reservoir.
• Do not reuse drained brake fluid; must use genuine specified brake fluid, using non-specified fluid may cause corrosion and shorten system life; if brake fluid splashes on paint, rinse immediately with water.
• If a single caliper has two bleed screws (fixed caliper), both bleed ports must be bled separately, perform the bleeding operation twice for that caliper.

Conventional Brake Component Inspection and Replacement

Brake light switch clearance: Standard 1.5~2.5mm. Adjustment method: remove cover panel, turn counterclockwise to remove switch, place a 1.5mm thick flat plate above the switch limit pad, insert switch into mounting bracket so that the contact is fully compressed on the flat plate, tighten clockwise, then remove the plate; press and release pedal several times, wait for natural return, then check clearance.

Brake pads (friction material thickness, not including steel backing):

Pads with wear indicators are installed on the inner side; for shims with double-sided tape, peel off the kraft paper first. Brake pad dust is toxic, must be cleaned with a vacuum cleaner, do not use suction hose or brush. After replacing brake pads, press the brake pedal several times before powering on, otherwise brake system warning may occur; new pads require larger pedal travel initially, pressing several times will restore.

Brake discs:

• Runout measured with dial indicator (measurement point 10mm from outer edge of disc); if over limit, machine with on-car brake lathe.
• Thickness measured with micrometer at 8 points 10mm from outer edge, spaced about 45° apart; if minimum measured value is less than machining limit, replace.
• Both brake discs on the same axle should be replaced simultaneously; use rust inhibitor during removal, do not forcibly remove disc from hub; machining requires uniform grinding of both sides and ensure wear allowance.

Common assembly torques:

Brake drag troubleshooting approach: Confirm and reproduce fault → check brake light switch clearance (1.5~2.5mm) and pedal return → lift vehicle and turn four wheels by hand → if drag, use VDS to enter "installation mode" and press brake pedal several times, then recheck wheel turning → if still drag, loosen the brake hose of that wheel's caliper and turn wheel again: if drag disappears, replace caliper assembly; if not, check brake line for blockage; if wheel turns normally in installation mode, replace IPB.

DTC Handling Key Points

• Wheel speed type (e.g., C056364): Check wheel speed sensor and tone ring clearance, foreign matter and electrical connections → check steering angle sensor and yaw rate sensor installation → IPB cross-verification, only replace IPB if ECU confirmed damaged.
• Pressure type (e.g., P229900 internal pressure sensor, C052F92 actual pressure deviates from set value beyond range): First diagnose CAN line hardware and software, then perform end-of-line bleeding to ensure no residual air in vehicle lines and IPB, re-power and verify.
• Power supply type (e.g., P056023): ECU supply voltage abnormal sets code—when just powered on below 4.5V, or during driving (speed >6km/h) voltage in 7~9.2V range triggers; measure ECU supply pin voltage (pin definitions in project circuit diagram), check battery, wiring harness, ground, finally cross-verify and replace IPB.
• Valve block type (solenoid valve and valve block relay faults): Cold soak 5 minutes to see if fault clears → measure solenoid valve supply pin voltage at connector → cross-verify and replace IPB; can accelerate to 15km/h then stop and diagnose again to confirm recurrence.
• Communication type (EMS/EPB/ADAS/body controller/front motor/TCU/wiper/steering angle sensor module communication faults): Unified approach—first diagnose CAN bus hardware and software → check corresponding module software version information → cross-verify to confirm module damaged, then replace corresponding module.
• Switch type (e.g., C004C04 PATA switch continuously pressed for more than 10 seconds): Check if switch is pressed by object and clean → check wiring harness → cross-verify and replace PATA switch.
• Configuration type: If configuration information not written or mismatched, use diagnostic tool to write IPB configuration information.

Safety Warnings

• This article is for technical reference; brake system maintenance directly affects driving safety, must be performed by certified personnel according to OEM specifications, readers unfamiliar are strictly prohibited from self-operation.
• Replacing IPB must follow the sequence of entering/exiting "installation mode", dry bleeding, configuration writing, and sensor calibration, all are indispensable; do not drive on road before calibration is complete.
• Incorrect brake hard line installation, insufficient torque, or damaged threads from sealing plugs may cause brake failure; brake fluid splashed on paint must be rinsed immediately with water.
• Do not deliver vehicle if bleeding unsuccessful (instrument still shows ABS/ESP warnings, abnormal pedal feel).

Maintenance Insights

The IPB system stitches together "mechanical braking" and "electro-hydraulic control". The biggest trap in maintenance is habitual thinking: traditional vehicles replacing the master cylinder is "disconnect lines, install, bleed air", but IPB adds a "software gate"—if you don't enter installation mode before disassembling and replacing parts, the system will degrade and lose boost; if you don't write configuration or calibrate, warning lights won't go out. Two most memorable experiences: one is "enter installation mode before bleeding, filling pressure capped at 2bar"—getting either detail wrong can damage hardware; two is "cross-verify before replacing parts"—IPB communication DTCs often point to other modules (EMS, EPB, ADAS, body controller), so check the other module first per the DTC table, only replace the other module if confirmed damaged, and only replace IPB after cross-verification confirms ECU failure, to avoid rework of "new assembly still has fault".

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【This article is for reference only】