Inspection Procedure

HINT:

When the brake warning light illuminates, inspect and repair the trouble areas of the brake booster vacuum line first.

1. CHECK BRAKE BOOSTER ASSEMBLY 
   1. Disconnect the A20 booster connector.
   2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance 

      RESISTANCE REFERENCE
      
      

      Tester Connection	Condition	Specified Condition
      3 (BST) - 4 (BSTP)	Always	1.1 to 1.7 Ω

   NG: REPLACE BRAKE BOOSTER ASSEMBLY  (See REMOVAL )

   Fig 1: Identifying Active Brake Booster Connector Terminal

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   OK: Go to Next Step 

2. CHECK HARNESS AND CONNECTOR (SKID CONTROL ECU - ACTIVE BRAKE BOOSTER) 
   1. Confirm that the skid control ECU connector and active brake booster connector are properly connected.
   2. Disconnect the A19 ECU connector.
   3. Disconnect the A20 booster connector.
   4. Inspect both the connector case and the terminal for deformation and corrosion.

      OK: No deformation or corrosion. 

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

      Standard Resistance 

      RESISTANCE REFERENCE
      
      

      Tester Connection	Condition	Specified Condition
      A19-17 (BST) - A20-3 (BST)	Always	Below 1 Ω
      A19-17 (BST) - Body ground	Always	10 kΩ or higher
      A19-31 (BSTP) - A20-4 (BSTP)	Always	Below 1 Ω
      A19-31 (BSTP) - Body ground	Always	10 kΩ or higher

   NG: REPAIR OR REPLACE HARNESS OR CONNECTOR 

   Fig 2: Identifying A20 Booster Connector Terminal And A19 ECU Connector Terminal

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   OK: REPLACE VSC ACTUATOR ASSEMBLY  (See REMOVAL  )