Kia Optima Hybrid: AHB(Active Hydraulic Boost) System / Brake Actuation Unit Repair procedures

Turn ignition switch OFF and disconnect the negative (-) battery cable.
Remove the air duct (A).

Remove air cleaner assembly (B).

Disconnect the brake fluid level switch connector (A), and remove the reservoir cap.

Be sure to completely remove foreign substances from around brake fluid reservoir and cap before opening the reservoir cap. If not, it may cause contamination of brake fluid and deterioration in braking performance.
Remove the brake fluid from the reservoir with a syringe.
Do not spill brake fluid on the vehicle, it may damage the paint; if brake fluid does contact the paint, wash it off immediately with water.
To prevent any dust entering in the reservoir, the reservoir cap should be closed again after removing brake fluid.
Disconnect reservoir hose from the reservoir and IBAU connecter (A).

Disconnect the brake tube from the IBAU by loosening the tube flare nut (B).
Before removing the IBAU, high pressure in an accumulator of PSU should be reduced for safety by conducting "High pressure release mode" of GDS connected to TF HEV.

Tighten torque:
13.7 ~ 16.7 N.m (1.4 ~ 1.7 kgf.m, 10.1 ~ 12.3 lb-ft)

Remove the brake pedal assembly. (Refer to the brake system group - brake pedal)
Remove the IBAU mounting nuts (A) and then remove the IBAU.

Tightening torque:
12.7 ~ 15.7 N.m (1.3 ~ 1.6 kgf.m, 9.4 ~ 11.6 lb-ft)

Installation is the reverse of removal.
Check the brake pedal operation.
After filling the brake fluid in the reservoir, perform the air bleed. (Refer to the Brakde system - Brake Bleeding Procedures)
Conduct calibration after removing the brake pedal assembly. (Refer to the brake pedal - calibration)
Brake Actuation Unit Components and Components Location

Components     IBAU must not be disassembled. 1. ECU2. Reservoir3. Master cylinder Assembley 4. Valve block ...

Pressure Source Unit Components and Components Location

Components     PSU must not be disassembled. 1. Motor connecter2. Bracket3. Block4. Accumulator5. Damper6. Motor ...

Other information:

Kia Optima Hybrid (TF HEV) 2016-2020 Service Manual: NVLD(Natural Vacuum Leakage Detection) Description and Operation

Description NVLD(Natural Vacuum Leakage Detection) is located between the canister and the fuel tank air filter. NVLD is to detect leaks equivalent to a 0.5 mm hole in the fuel tank, canister and hoses. When the engine has been running, the temperature of the fuel in the fuel tank is raised slightly. ...

Kia Optima Hybrid (TF HEV) 2016-2020 Service Manual: SS-B Solenoid Valve (ON/OFF) Repair procedures

Inspection 1. Turn ignition switch OFF. 2. Remove the air duct (A). Tightening torque: 7.8 ~ 9.8 N.m (0.8 ~ 1.0 kgf.m, 5.8 ~ 7.2 lb-ft) 3. Remove the air cleaner assembly. (1) Disconnect the breather hose (A). (2) Disconnect the air intake hose (B) and then remove the air cleaner assembly (C). Tightening ...

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