Inspection Procedure

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

HINT:

When C1241/41, C1252/52 or C1253/53 are output together with C1256/57, inspect and repair the trouble areas indicated by C1241/41, C1252/52 or C1253/53 first.
DTCs may be output if the accumulator pressure drops due to frequent braking (this is not a malfunction).

INSPECT BRAKE ACTUATOR ASSEMBLY

Disconnect the brake actuator assembly connector.

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

Resistance

TESTER CONNECTION SPECIFIED CONDITION REFERENCE CHART

Tester Connection	Specified Condition
A16-2 (BM1) - A16-31 (GND1)	Below 10 Ω
A16-1 (BM2) - A16-31 (GND1)	Below 10 Ω
A16-2 (BM1) - A16-1 (BM2)	Below 1 Ω
A16-31 (GND1) - A16-32 (GND2)	Below 1 Ω
A16-2 (BM1) - A16-33 (MTT)	About 33 Ω
A16-1 (BM2) - A16-33 (MTT)	About 33 Ω

Fig 1: Identifying Brake Actuator Assembly Connector Terminals

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

NG: REPLACE BRAKE ACTUATOR ASSEMBLY

OK: Go to next step

READ VALUE OF INTELLIGENT TESTER (ACCUMULATOR PRESSURE SENSOR)

Connect the intelligent tester to the DLC3.
Turn the engine switch on (IG).

Select the DATA LIST mode on the intelligent tester.

ABS / VSC:

NORMAL CONDITION CHART

Item (Display)	Measurement Item / Range (Display)	Normal Condition
ACC PRESS SENS	Accumulator pressure sensor/ min.: 0 V, max.: 5 V	Specified value: 2.6 to 3.8 V

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 (not braking).
OK:

ACC pressure sensor's output voltage does not drop.

NG: REPLACE BRAKE ACTUATOR ASSEMBLY

OK: Go to next step

RECONFIRM DTC

Clear the DTC (see DTC CHECK / CLEAR ).
Turn the engine switch on (IG).
Check if the same DTC is recorded (see DTC CHECK / CLEAR ).
HINT:

Reinstall the sensors, connectors, etc. and restore the vehicle to its prior condition before rechecking for DTCs.

Result

RESULT CHART

Display (DTC Output)	Proceed To
DTC (C1256/57) is not output	A
DTC (C1256/57) is output	B

B: REPLACE SKID CONTROL ECU

A: END