Inspection Procedure

1. Disconnect the A37 and A38 actuator connectors.
2. Connect the battery positive (+) lead to terminal 2 (BM1) or 3 (BM2) and battery negative (-) lead to terminal 1 (GND1) or 6 (GND2) of the brake actuator (pump motor).

   OK: Operation sound of pump motor should be heard. 

OK: Go to step   10 

Fig 1: Identifying A37 & A38 Actuator Connectors Terminals

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

NG: GO TO NEXT STEP 

NG: REPAIR OR REPLACE HARNESS AND CONNECTOR 

OK: GO TO NEXT STEP 

NG: REPAIR OR REPLACE HARNESS AND CONNECTOR 

OK: GO TO NEXT STEP 

1. Check the DATA LIST for proper functioning of the hydraulic brake boost pressure switch (PH) and (PL).
2. Depress the brake pedal more than 40 times with the ignition switch OFF. Then turn the ignition switch ON and check the pressure switch (PH) and (PL) condition.

   Skid control ECU assembly: 

   DATA LIST
   
   

   Item	Measurement Item/Range (Display)	Normal Condition	Diagnostic Note
   PRESS HIGH	HIGH Hydraulic brake boost pressure/ON or OFF	-	-
   PRESS LOW	LOW Hydraulic brake boost pressure/ON or OFF	-	-

   HINT:

   When pressure in power supply system is released, reaction force becomes light.

   OK: "OFF" turns to "ON" 

OK: REPLACE SKID CONTROL ECU ASSEMBLY 

NG: GO TO NEXT STEP 

1. Disconnect the A37 actuator connector.
2. With the ignition switch OFF, depress the brake pedal more than 40 times to decrease the accumulator pressure.

   HINT:

   When pressure in power supply system is released, reaction force becomes light.

3. Measure the resistance between terminal 3 (PH) and 5 (PHG) of the brake actuator connector.

   Standard resistance: 0.9 to 1.1 kΩ 

4. Connect the A37 actuator connector.
5. Disconnect the A37 actuator connector after the ignition switch has been ON and the pump motor has stopped.
   Fig 2: Identifying A37 Actuator Connector Terminals

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
6. Measure the resistance between terminal 3 (PH) and 5 (PHG) of the brake actuator.

   Standard resistance: Below 1 Ω 

   HINT:

   After inspection, connect the connector and clear the DTC.

NG: REPLACE BRAKE ACTUATOR 

OK: GO TO NEXT STEP 

1. Disconnect the A38 actuator connector.
2. With the ignition switch OFF, depress the brake pedal more than 40 times to decrease the accumulator pressure.

   HINT:

   When pressure in power supply system is released, reaction force becomes light.

3. Measure the resistance between terminal 4 (PL) and 2 (PLG) of the brake actuator connector.

   Standard resistance: 5.1 to 6.3 kΩ 

4. Connect the A38 actuator connector.
5. Disconnect the A38 actuator connector after the ignition switch has been ON and the pump motor has stopped.
   Fig 3: Identifying A38 Actuator Connector Terminals

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
6. Measure the resistance between terminal 4 (PL) and 2 (PLG) of the brake actuator.

   Standard resistance: 1.0 kΩ 

   HINT:

   After inspection, connect the connector and clear the DTC.

NG: REPLACE BRAKE ACTUATOR 

OK: GO TO NEXT STEP 

NG: REPAIR OR REPLACE HARNESS AND CONNECTOR 

OK: GO TO NEXT STEP 

1. Remove the ABS MTR 1 and ABS MTR 2 from the engine room relay block.
2. Measure the resistance of the relay.

   Standard resistance 

   TESTER CONNECTION AND SPECIFIED CONDITION
   
   

   Tester Connection	Specified Condition
   1 - 2	10 kΩ or higher
   1 - 2	Below 1 Ω (When battery voltage is applied to terminals 3 and 4)

   Fig 4: Identifying Relay Connector Terminals

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

NG: REPLACE RELAY 

OK: GO TO NEXT STEP 

NG: REPAIR OR REPLACE HARNESS AND CONNECTOR 

OK: REPLACE SKID CONTROL ECU ASSEMBLY 

NG: REPAIR OR REPLACE HARNESS AND CONNECTOR 

OK: GO TO NEXT STEP 

1. Check the brake actuator pump motor (see INSPECTION ).

NG: REPLACE BRAKE ACTUATOR PUMP MOTOR 

OK: REPLACE BRAKE ACTUATOR