Kia Soul EV: Brake System / Troubleshooting

Kia Soul EV (PS EV) 2015-2020 Service Manual / Brake System / Troubleshooting

Troubleshooting

Symptom	Possible Cause	Remedy
Lower pedal or spongy pedal	1. Integrated Brake Actuation Unit (Air in system)	Bleed air
	2. AHB system (Fluid leaks)	Replace
	3. Piston seals in IBAU (Worn or damaged)	Replace
Brake drag	1. Brake pedal free play (Minimum)	Adjust
	2. Pad or lining (Cracked or distorted)	Replace
	3. Piston (Stuck)	Replace
	4. Piston (Frozen)	Replace
	5. Anchor or Return spring (Inoperative)	Replace
	6. Master cylinder (Inoperative)	Replace
	7. IBAU (Inoperative)	Replace
Brake pull	1. Piston (Stuck)	Replace
	2. Pad or lining (Oily)	Replace
	3. Piston (Frozen)	Replace
	4. Disc (Scored)	Replace
	5. Pad or lining (Cracked or distorted)	Replace
Hard pedal but brake inefficient	1. Brake system (Fluid leaks)	Repair
	2. Brake system (Air in)	Bleed air
	3. Pad or lining (Worn)	Replace
	4. Pad or lining (Cracked or distorted)	Replace
	5. Rear brake shoe clearance(Out of adjustment)	Adjust
	6. Pad or lining (Oily)	Replace
	7. Pad or lining (Glazed)	Replace
	8. Disc (Scored)	Replace
	9. IBAU (Inoperative)	Replace
	10. PSU (Inoperative)	Replace
Noise from brake	1. Pad or lining (Cracked or distorted)	Replace
	2. Installation bolt (Loose)	Adjust
	3. Disc (Scored)	Replace
	4. Sliding pin (Worn)	Replace
	5. Pad or lining (Dirty)	Clean
	6. Pad or lining (Glazed)	Replace
	7. Brake pad shim (Damaged)	Replace
Brake fades	1. Pad or lining (Worn)	Replace
Brake fades	2. Master cylinder (Inoperative)	Replace
Brake vibration, pulsation	1. Pedal free play	Adjust
	2. Master cylinder (Inoperative)	Replace
	3. Caliper (Damaged)	Replace
	4. Master cylinder cap seal	Replace
	5. Damaged brake lines	Replace
Heavy pedal (Halt)	1. Brake pedal stuck (Lack of grease)	Repair
Heavy pedal (Halt)	2. IBAU (Inoperative)	Replace
Noisy electric motor and/or excessive braking force after 2 - 3 consecutive applications of brake pedal (When accumulator pressure increase rate is below 5bar/sec when sensor data was inspected after connecting to AHB module)	1. AHB system (air in system)	Bleed air
	2. PSU(Inoperative)	Replace
Excessive noise when pushing brake pedal	1. IBAU/PSU system (air in system)	Bleed air

The following operations may generate brake motor sound which is considered normal:

–	Repeated pushing on brake pedal

–	Pushing and releasing brake pedal during power off

–	Opening driver side door

The following cases are normal although the brake pedal may seem abnormal:

–	Noise when brake pedal is abruptly pushed

–	Noise when brake pedal is consecutively pushed

Special Service Tools

Special Service Tools Tool Name / NumberIllustrationDescription09581-11000Piston expanderUsed when spreading the front and rear disc brake piston.09580-3D100Air bleeding toolUsed when bleeding t ...

AHB(Active Hydraulic Boost) System

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Other information:

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