Vehicle Stability Control System (For Sedan) Brake Warning Light Remains On

DESCRIPTION

WIRING DIAGRAM

INSPECTION PROCEDURE

CHECK CAN COMMUNICATION SYSTEM

CHECK IF SKID CONTROL ECU CONNECTOR IS SECURELY CONNECTED

INSPECT BATTERY

INSPECT SKID CONTROL ECU (IG1 TERMINAL)

INSPECT SKID CONTROL ECU (GND TERMINAL)

READ VALUE USING TECHSTREAM (PARKING BRAKE SWITCH)

INSPECT BRAKE FLUID LEVEL WARNING SWITCH

CHECK HARNESS AND CONNECTOR (COMBINATION METER - BRAKE FLUID LEVEL WARNING SWITCH)

INSPECT COMBINATION METER ASSEMBLY

REPLACE COMBINATION METER ASSEMBLY

INSPECT COMBINATION METER ASSEMBLY

INSPECT PARKING BRAKE SWITCH

CHECK HARNESS AND CONNECTOR (MAIN BODY ECU - PARKING BRAKE SWITCH)

DESCRIPTION

1. The skid control ECU connector is disconnected from the skid control ECU.
   
2. The brake fluid level is insufficient.
   
3. The parking brake is applied.
   
4. EBD operation is not possible.
   

WIRING DIAGRAM

INSPECTION PROCEDURE

NOTICE:

When replacing the brake actuator assembly, perform zero point calibration (YARIS_NCP93 RM000000XHR06QX.html).

1. Check if CAN communication system DTCs are output (YARIS_NCP93 RM000001D3E00OX.html).
   

   Result

   Result	Proceed to
   DTC is not output	A
   DTC is output	B

1. Check if the skid control ECU connector is securely connected.
   

   OK:

   The connector is securely connected.
   

1. Check the battery voltage.
   

   Standard voltage:

   11 to 14 V
   

1. Disconnect the A30 skid control ECU connector.
   

2. Turn the ignition switch to ON.
   

3. Measure the voltage according to the value(s) in the table below.
   

   Text in Illustration

   *1	Front view of wire harness connector (to Skid Control ECU)

   Standard Voltage:

   Tester Connection	Switch Condition	Specified Condition
   A30-34 (IG1) - Body ground	Ignition switch ON	11 to 14 V

1. Turn the ignition switch off.
   

2. Measure the resistance according to the value(s) in the table below.
   

   Text in Illustration

   *1	Front view of wire harness connector (to Skid Control ECU)

   Standard Resistance:

   Tester Connection	Condition	Specified Condition
   A30-1 (GND1) - Body ground	Always	Below 1 Ω

1. Reconnect the skid control ECU connector.
   

2. Connect the Techstream to the DLC3.
   

3. Turn the ignition switch to ON.
   

4. Enter the following menus: Chassis / ABS/VSC/TRAC / Data List.
   
   

   ABS/VSC/TRAC (Skid Control ECU)

   Tester Display	Measurement Item/Range	Normal Condition	Diagnostic Note
   Parking Brake SW	Parking brake switch / ON or OFF	ON: Parking brake applied OFF: Parking brake released	-

5. Using the Techstream, check the input of the switch operation when the parking brake pedal is operated.
   

   OK:

   When the parking brake is operated, the display changes as shown above.
   

1. Turn the ignition switch off.
   

   Text in Illustration

   *1	Component without harness connected (Brake Fluid Level Warning Switch)

2. Remove the reservoir filler cap and strainer.
   

3. Disconnect the brake fluid level warning switch connector.
   

4. Measure the resistance according to the value(s) in the table below.
   

   HINT:

   A float is located inside the reservoir. Its position can be changed by increasing or decreasing the level of brake fluid.

   Standard Resistance:

   Tester Connection	Switch Condition	Specified Condition
   1 - 2	Switch OFF (Float up)	10 kΩ or higher
   1 - 2	Switch ON (Float down)	Below 1 Ω

   HINT:

   If there is no problem after finishing the above check, adjust the brake fluid level to the MAX level.

1. Disconnect the D76 or D2 combination meter connector.
   

2. Measure the resistance according to the value(s) in the table below.
   

   Standard Resistance:

   Tester Connection	Condition	Specified Condition
   D76-2 (SW) - A10-1	Always	Below 1 Ω
   D76-2 (SW) - Body ground	Always	10 kΩ or higher
   A10-2 - Body ground	Always	Below 1 Ω

1. Connect the Techstream to the DLC3.
   

2. Perform Active Test of the combination meter using the Techstream (YARIS_NCP93 RM000001DAT00FX.html).
   

   OK:

   The brake warning light turns ON or OFF in accordance with the Techstream.
   

   HINT:

   Reinstall the connectors and restore the vehicle to its prior condition before checking the combination meter.

1. Turn the ignition switch off.
   

2. Replace the combination meter (YARIS_NCP93 RM000000IN001JX.html).
   

1. Connect the Techstream to the DLC3.
   

2. Perform Active Test of the combination meter using the Techstream (YARIS_NCP93 RM000001DAT00FX.html).
   

   OK:

   The brake warning light turns ON or OFF in accordance with the Techstream.
   

1. Turn the ignition switch off.
   

   Text in Illustration

   *1	Component without harness connected (Parking Brake Switch)

2. Disconnect the parking brake switch connector.
   

3. Measure the resistance according to the value(s) in the table below.
   

   Standard Resistance:

   Tester Connection	Switch Condition	Specified Condition
   1 - Body ground	Parking brake switch ON (Switch pin free)	Below 1 Ω
   1 - Body ground	Parking brake switch OFF (Switch pin pushed in)	10 kΩ or higher

1. Disconnect the 4C main body ECU connector.
   

2. Measure the resistance according to the value(s) in the table below.
   

   Standard Resistance:

   Tester Connection	Condition	Specified Condition
   4C-2 (PKB) - D21-1	Always	Below 1 Ω
   4C-2 (PKB) - Body ground	Always	10 kΩ or higher