Brake Booster (Skid Control ECU) Communication Stop Mode [11/2022 - ]: Procedure

1. Disconnect the cable from the negative (-) auxiliary battery terminal.
2. Disconnect the electric brake booster (brake booster with master cylinder assembly) connector.
3. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   A189-2 (CA1H) - A189-12 (CA1L)	Cable disconnected from negative (-) auxiliary battery terminal	54 to 69 Ω

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   *a	Front view of wire harness connector (to Electric Brake Booster (Brake Booster with Master Cylinder Assembly))

   Result

   Proceed to
   OK
   NG

Result: 

NG 

REPAIR OR REPLACE CAN BRANCH LINES OR CONNECTOR (ELECTRIC BRAKE BOOSTER (BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY)) 

Result: 

OK 

See step  2

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

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   A189-26 (GND) - Body ground	Cable disconnected from negative (-) auxiliary battery terminal	Below 1 Ω

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   *a	Front view of wire harness connector (to Electric Brake Booster (Brake Booster with Master Cylinder Assembly))

2. Reconnect the cable to the negative (-) auxiliary battery terminal.
3. Measure the voltage according to the value(s) in the table below.

   Standard Voltage

   Tester Connection	Switch Condition	Specified Condition
   A189-11 (+BS) - Body ground	Ignition switch off	11 to 14 V
   A189-4 (IGR) - Body ground	Ignition switch ON	11 to 14 V

   Result

   Proceed to
   OK
   NG

Result: 

OK 

REPLACE ELECTRIC BRAKE BOOSTER (BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY) 

Refer to REMOVAL [11/2022 - ]

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR (POWER SOURCE CIRCUIT)