Inspection Procedure

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).

1. INSPECT BRAKE ACTUATOR ASSEMBLY 
   1. Disconnect the A16 actuator connector.
   2. Measure the resistance according to the value(s) in the table below.

      Standard resistance 

      TESTER CONNECTION SPECIFIED CONDITION
      
      

      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 A16 Connector Terminals

      Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   NG: REPLACE BRAKE ACTUATOR ASSEMBLY (See  REMOVAL   ) 

   OK: GO TO Next Step 

2. READ VALUE OF INTELLIGENT TESTER (ACCUMULATOR PRESSURE SENSOR) 
   1. Connect the intelligent tester to the DLC3.
   2. Turn the power switch ON (IG).
   3. Select the DATA LIST mode on the intelligent tester.

      Skid control ECU: 

      DATA LIST
      
      

      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

   4. 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 (See  REMOVAL   ) 

   OK: GO TO Next Step 

3. RECONFIRM DTC 
   1. Clear the DTC (see DTC CHECK / CLEAR  ).
   2. Turn the power switch ON (IG).
   3. 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
      
      

      Condition	Proceed to
      DTC (C1256/57) is not output	A
      DTC (C1256/57) is output	B

   B: REPLACE SKID CONTROL ECU (See  REMOVAL   ) 

   A: END