Inspection Procedure

HINT:

When 01253/53, 01254/54, or 01256/56 is output together with 01252/52, inspect and repair the trouble area indicated by 01253/53, 01254/54, or 01256/56 first.

1. CHECK PUMP MOTOR OPERATION 
   1. Turn the engine switch off.
   2. Depress the brake pedal more than 20 times.
   3. Turn the engine switch on (IG).
   4. Check how the pump motor operates.

      Result 

      RESULT REFERENCE
      
      

      Result	Proceed to
      Pump motor does not operate	A
      Pump motor operates continuously, and does not stop	B
      Pump motor operates intermittently	C
      Pump motor operates, then stops	D

   B: REPLACE HYDRAULIC BRAKE BOOSTER ASSEMBLY  (See REMOVAL )

   C:  Go to step  4

   D:  Go to step  5

   A: Go to Next Step 

2. CHECK CONNECTION OF PUMP MOTOR WIRE HARNESS 
   1. Remove the hydraulic brake booster assembly (See REMOVAL ).
   2. Using a screwdriver, remove the 2 plugs from the hydraulic brake booster assembly (See DISASSEMBLY ).
   3. Check the tightening torque of the 2 screws which tighten the wire harness connecting the hydraulic brake booster assembly and brake booster pump (See REASSEMBLY ).

      OK: The harness is tightened to the specific torque. 

      Torque: 2.9 N*m (30 kgf*cm, 26 in.*lbf) 

   NG: RETIGHTEN SCREWS 

   OK: Go to Next Step 

3. CHECK RESISTANCE OF PUMP MOTOR WIRE HARNESS 
   1. Using a screwdriver, remove the 2 screws and pull the wire harness from the hydraulic brake booster assembly.
   2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance 

      STANDARD RESISTANCE SPECIFICATION
      
      

      Tester Connection	Condition	Specified Condition
      Red wire terminal - Black wire terminal	Always	2 Ω

   NG: REPLACE BRAKE BOOSTER PUMP ASSEMBLY  (See DISASSEMBLY )

   Fig 1: Identifying Pump Motor Red And Black Wire

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   OK: Go to Next Step 

4. READ VALUE USING TECHSTREAM (ACCUMULATOR SENSOR) 
   1. Connect the Techstream to the DLC3.
   2. Turn the engine switch on (IG) and turn the Techstream on.
   3. Enter the following menus: Chassis / ABS/VSC/TRAC / Data List.

      ABS/VSC/TRAC 

      DATA LIST - ABS/VSC/TRAC
      
      

      Tester Display	Measurement Item/Range	Normal Condition	Diagnostic Note
      Accumulator Sensor	Accumulator pressure sensor reading/min.: 0 V, max.: 5 V	3.58 to 5 V	If the value is constant regardless of the pump operation, an accumulator pressure sensor malfunction is suspected.

   4. Check the accumulator output value.

      Result 

      RESULT REFERENCE
      
      

      Result	Proceed to
      Output value is within the "Normal Condition" range	A
      Output value is out of the "Normal Condition" range	B
      Output value is constant regardless of pump operation	C

   B: REPLACE MASTER CYLINDER SOLENOID  (See DISASSEMBLY )

   C: REPLACE HYDRAULIC BRAKE BOOSTER ASSEMBLY  (See REMOVAL )

   A: Go to Next Step 

5. RECONFIRM DTC 
   1. Clear the DTC (See DTC CHECK/CLEAR  ).
   2. Turn the engine switch off.
   3. Turn the engine switch on (IG).
   4. Wait for more than 5 minutes.
   5. Check if the same DTC is output (See DTC CHECK/CLEAR  ).

   HINT:

   Reinstall the sensors, connectors, etc. and restore the previous vehicle conditions before rechecking for DTCs.

   Result 

   RESULT REFERENCE
   
   

   Result	Proceed to
   DTC is output	A
   DTC is not output	B

   B: REPLACE BRAKE BOOSTER WITH ACCUMULATOR PUMP ASSEMBLY  (See DISASSEMBLY )

   A: REPLACE HYDRAULIC BRAKE BOOSTER ASSEMBLY  (See REMOVAL )