Kia Optima: Hydraulic System / Underdrive Brake Control Solenoid Valve (UD/B_VFS)

Kia Optima DL3 2019-2023 Service and Repair Manual / Automatic Transaxle System / Hydraulic System / Underdrive Brake Control Solenoid Valve (UD/B_VFS)

Specifications

Specification

Item	Specification
Control type	N/H (Normal High)
Control pressure (kpa (kgf/cm², psi))	0 - 1,569.06 (0 - 16, 0 - 227.57)
Currency (mA)	0 - 1,100
Coil resistance(Ω)	5.3 ± 0.3

Description and operation

Description

•	Underdrive brake control solenoid valve is a Variable Force Solenoid (VFS) type.

•	When TCM supplies variable current to solenoid valve, hydraulic pressure of underdrive brake is controlled by solenoid valve.

Underdrive brake control solenoid valve operation table

	UD/B_VFS
	N/H
N, P	●
1
2
3
4
5	●
6	●
R	●

● : Connected status

Components and components location

Component Location

1. Valve Body Cover	8. SS-A ON/OFF Solenoid Valve
2. Valve Body Gasket	9. Torque Converter Control Solenoid Valve
3. Main Harness	10. Line Pressure Control Solenoid Valve
4. 26 Brake Control Solenoid Valve	11. Support Bracket
5. 35R Clutch Control Solenoid Valve	12. Support Bracket
6. Underdrive Brake Control Solenoid Valve
7. Overdrive Clutch Control Solenoid Valve

Repair procedures

Inspection

The automatic transaxle system can be more quickly diagnosed for troubles by using the vehicle diagnostic system (KDS).

KDS provides the following information.

(1)	Self diagnosis : Inspects and displays diagnostic trouble code (DTC)

(2)	Sensor data : Checks the system input/output value status

(3)	Forced operation : Checks the system operating status

(4)	Additional function : Controls system options, zero point adjustment and other functions

Component inspection

1.	Switch "OFF" ignition.

2.	Remove the air cleaner assembly. (Refer to Engine Mechanical System - "Air cleaner")

3.	Remove the battery and battery tray. (Refer to Engine Electrical System - "Battery")

4.	Disconnect the solenoid valve connector (A).

Measure the resistance between power terminal (5) and signal terminal (16).

Specification : 5.3 ± 0.3 Ω

Removal

•

•	Automatic transaxle is composed of delicate components. Be careful not to cause any damage on the component in the course of assembly and disassembly.

•	Maintain clean condition so that foreign substance does not get into the automatic transaxle.

•	Use a coated apron, latex gloves, and stainless tray to prevent foreign substance from getting into the transaxle.

1.	Remove the under cover. (Refer to Engine Mechanical System - "Engine Room Under Cover")

Remove the ATF drain plug (A), allow the fluid to drain out and then reinstall the drain plug.

Tightening torque:

33.3 - 43.1 N·m (3.4 - 4.4 kgf·m, 24.6 - 31.8 lb·ft)

•	The existing ATF drain plug gasket must be replaced with a new one. (Do not reuse it.

•	Automatic transaxle fluid (ATF) can be reused. Collect it using a clean 10-liter beaker.

3.	Remove the air duct and air cleaner assembly. (Refer to Engine Mechanical System - "Air cleaner")

Remove the fixing clip (A) and the air breather hose (B).

Tightening torque:

9.8 - 11.8 N·m (1.0 - 1.2 kgf·m, 7.2 - 8.7 lb·ft)

5.	Separate the ATF cooler hose (A).

6.	Lift the vehicle after loosening valve body cover upper bolts.

Remove the valve body cover (A) by loosening bolts.

Tightening torque:

11.8 - 13.7 N·m (1.2 - 1.4 kgf·m, 8.7 - 10.1 lb·ft)

Remove the main harness (A) after removing the bolts.

Tightening torque:

9.8 - 11.8 N·m (1.0 - 1.2 kgf·m, 7.2 - 8.7 lb·ft)

Remove solenoid valve support bracket (A) after loosening the bolts.

Tightening torque:

9.8 - 11.8 N·m (1.0 - 1.2 kgf·m, 7.2 - 8.7 lb·ft)

10.

Remove the solenoid valve fixing pin (A) and loosen the valve body mounting bolt (B).

Tightening torque:

9.8 - 11.8 N·m (1.0 - 1.2 kgf·m, 7.2 - 8.7 lb·ft)

11.	Remove the underdrive brake control solenoid valve (A).

Installation

Install in the reverse order of removal.

•	The existing valve body cover gasket (A) must be replaced with a new one. (Do not reuse it.)

•	Check the code (oil pressure characteristics value) at the first before installing the solenoid valve.

Perform the procedures below after installing.

(1)	Refill the automatic transaxle with fluid. (Refer to Hydraulic System - "Fluid")

(2)	Clear the diagnostic trouble codes (DTC) using the KDS. Disconnecting the battery negative terminal will not clear the DTCs. Clear DTCs using the KDS at all times.

(3)	Reset the automatic transaxle adaptive values using the KDS.

(4)	Perform the oil pressure characteristics input procedure using the KDS. (Refer to Hydraulic System - "Oil pressure characteristics input")

(5)	Check for leakage of coolant or fluid from hose connection during engine start.

(6)	Perform the TCM adaptive values learning procedure. (Refer to Automatic Transaxle Control System - "Adjustment")

26 Brake Control Solenoid Valve (26/B_VFS)

Specifications Specification Item Specification Control type N/L (Normal Low) Control pressure (kpa (kgf/cm², ps ...

Overdrive Clutch Control Solenoid Valve (OD/C_VFS)

Specifications Specification Item Specification Control type N/H (Normal High) Control pressure (kpa (kgf/cm², p ...

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