Inspection Procedure

NOTE: When replacing the skid control ECU, perform initialization of linear solenoid valve and calibration (see INITIALIZATION ).

CHECK WIRE HARNESS (SKID CONTROL ECU-BRAKE ACTUATOR)

Disconnect the S7 ECU connector
Disconnect the A2 actuator connector.

Measure the resistance of the wire harness side connectors.

Standard resistance

STANDARD RESISTANCE REFERENCE CHART

Tester Connection	Specified Condition
S7-8 (E) - A2-45 (E1)	Below 1 Ω
S7-9 (VCM1) - A2-35 (VCM1)	Below 1 Ω
S7-21 (PACC) - A2-46 (PACC)	Below 1 Ω
S7-31 (PCK1) - A2-37 (PCK1)	Below 1 Ω
S7-8 (E) - Body ground	10 kΩ or higher
S7-9 (VCM1) - Body ground	10 kΩ or higher
S7-21 (PACC) - Body ground	10 kΩ or higher
S7-31 (PCK1) - Body ground	10 kΩ or higher

NG: REPAIR OR REPLACE HARNESS AND CONNECTOR

Fig 1: Disconnecting S7 ECU Connector

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

OK: Go to next step

CHECK SKID CONTROL ECU (VCM1 VOLTAGE)

Measure the voltage of the connector.

HINT:

Measure the voltage from behind the connector with the connector connected to the skid control ECU.

Standard voltage

STANDARD VOLTAGE SPECIFICATION

Tester Connection	Condition	Specified Condition
S7-9 (VCM1) - S7-1 (GND)	Power switch ON (READY)	4.75 to 5.25 V

NG: REPLACE SKID CONTROL ECU

Fig 2: Checking Skid Control ECU (VCM1 Voltage)

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

OK: Go to next step

CHECK SKID CONTROL ECU ASSEMBLY (PACC VOLTAGE)

Check the auxiliary battery voltage.
Standard voltage:

10 to 14 V
Depress the brake pedal to operate the pump motor, and then check that the pump motor stops.

Measure the voltage of the connector.

Standard voltage

STANDARD VOLTAGE SPECIFICATION

Tester Connection	Specified Condition
S7-21 (PACC) - S7-1 (GND)	3.3 to 4.7 V

Fig 3: Checking Skid Control ECU Assembly (PACC Voltage)

NOTE:

Do not depress the brake until after the pump motor stops and the voltage check is finished in order to keep the accumulator pressure.
Check from behind the connector with the connector connected to the skid control ECU.
Do not use a DATA LIST, as the sensor itself must be checked.

NG: REPLACE BRAKE ACTUATOR ASSEMBLY

OK: Go to next step

READ VALUE OF INTELLIGENT TESTER (ACCUMULATOR PRESSURE SENSOR)

Check the DATA LIST for proper functioning of the accumulator pressure sensor.

Depress the brake pedal 4 or 5 times to operate the pump motor, and check the output value on the intelligent tester with the motor stopped (no braking).

Skid control ECU

SKID CONTROL ECU DIAGNOSTIC CHART

Item	Measurement Item / Range (Display)	Normal Condition	Diagnostic Note
ACC PRESS SENS 1	Accumulator pressure sensor 1 / Min.: 0V, Max.: 5V	Specified value: 3.2 to 4.0 V	-

OK:

Accumulator pressure sensor voltage does not drop.

NG: REPLACE BRAKE ACTUATOR ASSEMBLY

OK: REPLACE SKID CONTROL ECU