Kia Optima: Brake System / ESC (Electronic Stability Control) System

Kia Optima DL3 2019-2020 Service and Repair Manual / Brake System / ESC (Electronic Stability Control) System

Components and components location
Components

1. ESC control module (HECU)
2. Front wheel speed sensor
3. Rear wheel speed sensor
4. ABS warning lamp
5. Parking brake/ EBD warning lamp

Description and operation
Description of ESC

Electronic Stability Control (ESC) recognizes critical driving conditions, such as panic reactions in dangerous situations, and stabilizes the vehicle by individual wheel braking and engine control input.

ESC adds an additional function known as Active Yaw Control (AYC) to the ABS, TCS, EBD and ESC functions. On contrary, the ABS/TCS function controls wheel slip during braking and accelerating, and thus, mainly intervenes in the longitudinal dynamics of the vehicle, and the active yaw control stabilizes the vehicle on the vertical axis.

This is achieved by individual wheel brake intervention and adaptation of momentary engine torque with no need for any action to be taken by the driver.

ESC essentially consists of three assemblies : the sensors, the electronic control unit and the actuators.

The stability control feature works under all driving and operating conditions. Under certain driving conditions, the ABS/TCS function can be activated simultaneously with the ESC function in response to a command by the driver.

In the event of a failure of the stability control function, the basic safety function, ABS, is still maintained.

Description of ESC Control

ESC system consists of ABS/EBD, TCS and AYC functions.

ABS/EBD function : The ECU changes the active sensor signal (current shift) coming from the four wheel sensors into square waves. By using the input of above signals, the ECU calculates the vehicle speed and the acceleration & deceleration of the four wheels. And, the ECU judges whether the ABS/EBD should be actuated or not.

TCS function prevents the wheel slip of drive direction by adding the brake pressure and engine torque reduction via CAN communication. TCS function uses the wheel speed sensor signal to determine the wheel slip as far as ABS function.

AYC function prevents unstable maneuver of the vehicle. To determine the vehicle maneuver, AYC function uses the maneuver sensor signals (Yaw Rate Sensor, Lateral Acceleration Sensor, and Steering Wheel Angle Sensor).

If vehicle maneuver is unstable (Over Steer or Under Steer), AYC function applies the brake pressure on certain wheel, and sends engine torque reduction signal by CAN.

After the key-on, the ECU continuously diagnoses the system failure (self-diagnosis). If the system failure is detected, the ECU informs driver of the system failure through the BRAKE/ABS/ESC warning lamp (fail-safe warning).

Input and Output Diagram

ESC Operation Mode
ESC / ESCi

ESCi+

1.

ESC Non-operation : Normal braking.

Solenoid Valve
Continuity
Valve
Motor Pump
TC Valve
IN (NO)
OFF
OPEN
OFF
OFF
OUT (NC)
OFF
CLOSE

2.

ESC operation

Solenoid Valve
Continuity
Valve
Motor Pump
TC Valve
Understeering
(Only inside of rear wheel)
IN (NO)
OFF
OPEN
ON
ON
OUT (NC)
OFF
CLOSE
Oversteering
(Only outside of front wheel)
IN (NO)
OFF
OPEN
OUT (NC)
OFF
CLOSE

Warning Lamp Control

ABS Warning Lamp module

The active ABS warning lamp module indicates the self-test and failure status of the ABS. The ABS warning lamp is turned on under the following conditions:

During the initialization phase after IGN ON. (continuously 3 seconds).

In the event of ABS function failure.

During diagnostic mode.

When the communication between HECU and PCM has failed.

Cluster lamp is ON when communication is impossible with CAN module.

EBD/Parking Brake Warning Lamp Module

The active EBD warning lamp module indicates the self-test and failure status of the EBD. However, in case the Parking Brake Switch is turned on, the EBD warning lamp is always turned on regardless of EBD functions. The EBD warning lamp is turned on under the following conditions:

During the initialization phase after IGN ON. (continuously 3 seconds).

When the Parking Brake Switch is ON or brake fluid level is low.

When the EBD function is out of order.

During diagnostic mode.

When the communication between HECU and PCM has failed.

Cluster lamp is ON when communication is impossible with CAN module.

ESC Function/Warning Lamp

The ESC function/warning lamp indicates the self-test and failure status of the ESC.

The ESC function/warning lamp is turned on under the following conditions:

During the initialization phase after IGN ON. (continuously 3 seconds).

When the ESC function is inhibited by system failure.

When the ESC control is operating. (Blinking - 2Hz)

During diagnostic mode.(Except standard mode)

Cluster lamp is ON when communication is impossible with CAN module.

ESC Off Lamp

The ESC Off lamp indicates the self-test and operating status of the ESC.

The ESC Off lamp operates under the following conditions :

During the initialization mode after IGN ON. (continuously 3 seconds).

ESC Off lamp is ON when driver turns OFF ESC switch.

ESC On/Off Switch

The ESC On/Off Switch is used to toggle the ESC function between On/Off states based upon driver input.

The On/Off switch is a normally open, is a momentary contact switch.

Initial status of the ESC function is ON.

Schematic diagrams
Circuit Diagram

[EPB None Apply]

[EPB Apply]

Terminal Function

[EPB None Apply]

PIN No
Desciption
Current
max
min
1
Voltage supply for pump motor
40A
10 MΩ
2
Hazard switch
1.2 mA
250 MΩ
3
-


6



7
P-CAN LOW
100 mA
250 MΩ
8
P-CAN High
100 mA
250 MΩ
9
Wheel speed sensor power voltage (RL)
100 mA
250 MΩ
10
Wheel speed sensor power voltage (RR)
100 mA
250 MΩ
11
Wheel speed sensor power voltage (FR)
100 mA
250 MΩ
12
Wheel speed sensor power voltage (FL)
100 mA
250 MΩ
13
Recirculation pump ground
40A
10 MΩ
14
-


17
ESC Switch
1.2 mA
250 MΩ
18
-


19
Parking brake switch
1.2 mA
250 MΩ
20
-


21
Wheel speed sensor ground (RL)
40 mA
250 MΩ
22
Wheel speed sensor ground (RR)
40 mA
250 MΩ
23
Wheel speed sensor ground (FR)
40 mA
250 MΩ
24
Wheel speed sensor ground (FL)
40 mA
250 MΩ
25
Voltage supply for solenoid valves
30A
10 MΩ
26
-


27
-


28



29
-


30
Brake lamp switch
1.2 mA
250 MΩ
31
-


32
IGN 1
10mA
50MΩ
33
-


36
-


37
Wheel speed sensor output (FR)
50 mA
250 MΩ
38
Ground for solenoid valves and ECU
30A
10 MΩ

[EPB Apply]

PIN No
Desciption
Current
max
min
1
Voltage supply for pump motor
39A
10 MΩ
2
RR EPB motor power
30A
10 MΩ
3
RR EPB motor ground
30A
10 MΩ
6
Electric parking brake signal 1 
20 mA
250 MΩ
7
Electric parking brake signal 2
20 mA
250 MΩ
8
Electric parking brake signal 3
20 mA
250 MΩ
9
Electric parking brake signal 4
20 mA
250 MΩ
10

-
250 MΩ
11

-
-
12
RL EPB motor ground
30A
-
13
RL EPB motor power
30A
10 MΩ
14
Ground for solenoid valves and ECU
30A
10 MΩ
16
-
-
250 MΩ
17
ESP OFF switch signal
16.8 mA

19
Local CAN High
10 mA
250 MΩ
20
Local CAN Low
30 mA
250 MΩ
21
-
-
250 MΩ
22
P-CAN LOW
-

23
P-CAN High
200 mA
250 MΩ
24
-
-
250 MΩ
25
Wheel speed sensor supply voltage (RL)
16.8 mA

26
Wheel speed sensor supply voltage (RR)
16.8 mA
250 MΩ
27
Wheel speed sensor supply voltage (FR)
16.8 mA
250 MΩ
28
Wheel speed sensor supply voltage (FL)
-
250 MΩ
29
-
16.8 mA
250 MΩ
30
Voltage supply for solenoid valves
30A

31
-
-
10 MΩ
32
-
Open drain

33
-
-

34
Auto holding ON/OFF switch signal 
10 mA

35
Brake light switch
10 mA
250 MΩ
37
IGN 1 
5A
250 MΩ
39
-
16.8 mA
250 MΩ
40
-
-

41
-
-

42
-
-
250 MΩ
43
-
-
250 MΩ
44
Wheel speed sensor ground (FL)
30 mA
250 MΩ
45
Wheel speed sensor ground (FR)
30 mA
250 MΩ
46
Recirculation pump ground
40A
250 MΩ

Troubleshooting
Troubleshooting

Failure Diagnosis

1.

In principle, ESC and TCS controls are prohibited in case of ABS failure.

2.

When ESC or TCS fails, only the failed system control is prohibited.

3.

The solenoid valve relay should be turned off in case of ESC failure, refer to the ABS fail-safe.

4.

Information on ABS fail-safe is identical to the fail-safe in systems where ESC is not installed.

Memory of Fail Code

1.

It keeps the code as far as the backup lamp power is connected. (O)

2.

It keeps the code as far as the HCU power is on. (X)

Failure Checkup

1.

Initial checkup is performed immediately after the HECU is powered on.

2.

Valve relay checkup is performed immediately after switching "ON" the IG2.

3.

It executes the checkup all the time while the IG2 is switched "ON".

4.

Initial checkup is made in the following cases.

(1)

When the failure is not detected momentarily

(2)

When ABS and ESC are not in control.

(3)

If initial checkup is not made after supplying power to ECU.

(4)

If the vehicle speed is over 5 mph (8 km/h) with the brake lamp switched off.

(5)

When the vehicle speed is over 24.8 mph (40 km/h).

5.

Check up continues even if the brake lamp is switched on.

6.

When performing ABS or ESC control before the initial checkup, stop the initial checkup and wait for the HECU power input again.

7.

Judge failure in the following cases.

(1)

When the power is normal.

(2)

From the point in which the vehicle speed reaches 4.9 mph(8 km/h) after HECU power on.

Countermeasures in Fail

1.

Turn the system down and perform the following actions and wait for HECU to power OFF.

2.

Turn the valve relay off.

3.

Stop the control during the operation and do not execute anything until it recovers to normal condition.

Warning Lamp ON

1.

ESC warning lamps turns on for 3 seconds after IGN ON.

2.

ESC function lamp blinks when ESC Act.

3.

In case of ESC failure, ESC warning lamp turns ON.

4.

ESC OFF lamp turns on:

– When ESC is switched OFF

–3 seconds after IGN ON

Electric Parking Brake (EPB)
Description and operation Description The electronic parking brake (EPB) is different from existing parking systems which operated with the brake pedal or the lever type. The EPB syste ...

ESC Control Module
Components and components location Components 1. Front - right (FR) 2. Rear - left (RL) 3. Rear - right (RR) 4. Front - left (FL) 5. MC2 6. MC1 7 ...

Other information:

Kia Optima DL3 2019-2020 Service and Repair Manual: Side Airbag (SAB) Module


Description and operation Description The Side Airbags (SAB) are installed inside the front seat and protects the driver and passenger from danger when a side crash occurs. The SRSCM determines deployment of the side airbag by using the Side Impact Sensor (SIS) signal. ...

Kia Optima DL3 2019-2020 Service and Repair Manual: Delivery Pipe


Components and components location Components 1. Clip 2. Delivery Pipe 3. Injector Repair procedures Removal 1. Release the residual pressure in fuel line. (Refer to Fuel Delivery System - "Release Residual Pre ...

Copyright © www.kioptima.com 2017-2020