Inspection Procedure

HINT:

When C1253/53, C1254/54, or C1256/56 is output together with C1252/52, inspect and repair the trouble area indicated by C1253/53, C1254/54, or C1256/56 first.

1. Check operation of the hydraulic brake booster pump motor. 

   PREPARATION: 

   1. Turn the ignition switch OFF.
   2. Depress the brake pedal more than 20 times.
   3. Turn the ignition switch to the ON position.

   CHECK: 

   Check how the hydraulic brake booster pump motor operates.

   RESULT: 

   HYDRAULIC BRAKE BOOSTER PUMP MOTOR OPERATION RESULT
   
   

   Pump motor does not operate	A
   Pump motor operates continuously (does not stop)	B
   Pump motor operates intermittently	C
   Pump motor operates, then stops	D

   1. B : Replace master cylinder solenoid and pump motor assembly w/ accumulator assembly (See  DISASSEMBLY  ). 
   2. C : Go to step   4 . 
   3. D : Go to step   5 . 
   4. A : Go to next step. 
2. Check connectivity of the brake pump motor wire harness (MT+/MT-). 

   PREPARATION: 

   Using a screwdriver, remove the 2 plugs from the hydraulic brake booster assembly (see DISASSEMBLY ).

   CHECK: 

   Check the tightening torque of the 2 screws which tighten the wire harness connecting the hydraulic brake booster assembly and the brake booster pump (see DISASSEMBLY ).

   OK: 

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

   1. NG : Tighten the screws up, then go to step   5 . 
   2. OK : Go to next step. 
3. Check resistance of pump motor (MT+/MT-) wire harness. 

   PREPARATION: 

   Using a screwdriver, remove the 2 screws and pull the wire harness from the hydraulic brake booster assembly (see DISASSEMBLY ).

   CHECK: 

   Measure the resistance between the red wire (MT+) and the black wire (MT-).

   OK: 

   Resistance: 2 Ω 

   Fig 1: Identifying Pump Motor (MT+/MT-) Wire Harness

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
   1. NG : Replace pump motor assembly w/ accumulator (See  DISASSEMBLY  ). 
   2. OK : Go to next step. 
4. Check internal pressure leak. 

   PREPARATION: 

   1. Connect the hand-held tester to the DLC3.
   2. Turn the ignition switch to the ON position.
   3. Select the DATA LIST mode on the hand-held tester.
   DATA LIST MODE REFERENCE
   
   

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

   CHECK: 

   Check that the accumulator output is normal.

   RESULT: 

   ACCUMULATOR OUTPUT RESULT
   
   

   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 motor operation	C

   1. B : Replace hydraulic brake booster (See  REMOVAL  ). 
   2. C : Replace master cylinder solenoid and pump motor assembly w/ accumulator assembly (See  DISASSEMBLY  ). 
   3. A : Go to next step. 
5. Reconfirm DTC (See  DTC CHECK / CLEAR   ). 

   PREPARATION: 

   1. Clear the DTCs.
   2. Turn the ignition switch OFF.
   3. Turn the ignition switch to the ON position.
   4. Wait for more than 5 minutes.

   CHECK: 

   Check if the same DTCs are detected.

   RESULT: 

   DTC OUTPUT RESULT
   
   

   DTC is output	A
   DTC is not output	B

   1. B : Replace pump motor assembly w/ accumulator assembly (See  DISASSEMBLY  ). 
   2. A : Replace master cylinder solenoid and pump motor assembly w/ accumulator assembly (See  DISASSEMBLY  ).