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: Steering Angle Sensor Description and Operation

Description The Steering Angle Sensor (SAS) is installed in MDPS (Motor Driven Power Steering) and it sends messages to HECU through CAN communication line. The SAS is used to determine turning direction and speed of the steering wheel. The HECU uses the signals from the SAS when performing ESC-related ...

Kia Optima Hybrid (TF HEV) 2016-2020 Service Manual: Repair procedures

Inspection Check it by the procedure below to see if the function of the ECM is normal. 1. Turn the ignition key to the "ON" position. 2. Cover the front sensor to stop functioning. 3. Shine a light at the rear sensor. 4. The ECM should be darkened as soon as the rear sensor detects the light.   ...

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