DTC C1391-00: Abnormal Leak in Accumulator [12/2019 - ]: Procedure
- READ VALUE USING GTS (SERVO PRESSURE)
- Perform the Active Test and operate the linear solenoid (SLR) in the brake booster with master cylinder assembly.
- Check that the servo pressure output value does not increase when performing the Active Test.
Chassis > Brake Booster > Active Test
Tester Display Measurement Item Control Range Restrict Condition Diagnostic Note ECB Solenoid (SLR) Linear solenoid reduction valve (SLR) Solenoid Start (Activate)
Solenoid SLR
(It is possible to set the current)Vehicle condition: - Vehicle stopped
- Shift lever is in P
- Apply the parking brake
ECB: Electronically Controlled Brake System Chassis > Brake Booster > Data List
Tester Display Measurement Item Range Normal Condition Diagnostic Note Servo Pressure Pressure value of servo Min.: 0.00 MPa
Max.: 24.48 MPaBrake pedal released: 0.00 to 1.53 MPa Brake pedal is being depressed: Changes in proportion to the depression force of the brake pedal Chassis > Brake Booster > Active Test
Active Test Display ECB Solenoid (SLR) Data List Display Servo Pressure OK
The servo pressure output value does not increase when performing the Active Test.
HINT:
- If the servo pressure output value increases, an internal brake fluid leak in the brake booster with master cylinder assembly is suspected.
- Perform the Active Test with the current set to maximum.
Result
Result Proceed to The servo pressure output value increases. A The servo pressure output value does not increase. B
Result:
A
REPLACE BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY. Refer to REMOVAL [12/2019 - 10/2022] , or refer to REMOVAL [10/2022 - 11/2023] , or refer to REMOVAL [11/2023 - ]
Result:
B
See step 2
- CHECK OPERATING TIME OF PUMP MOTOR
- With the ignition switch is turned to ON (READY), check the operation of the pump motor.
Chassis > Brake Booster > Data List
Tester Display Measurement Item Range Normal Condition Diagnostic Note ECB Motor Relay Motor relay operation request OFF / ON OFF: Relay off
ON: Relay onECB: Electronically Controlled Brake System Chassis > Brake Booster > Data List
Tester Display ECB Motor Relay Result
Result Proceed to The pump motor operates once or more within 20 seconds or operates for 10 seconds or more each time. A Other than above. B
Result:
B
REPLACE BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY. Refer to REMOVAL [12/2019 - 10/2022] , or refer to REMOVAL [10/2022 - 11/2023] , or refer to REMOVAL [11/2023 - ]
Result:
A
See step 3
- With the ignition switch is turned to ON (READY), check the operation of the pump motor.
- CHECK FOR FLUID LEAK
- Check for brake fluid leaks in the line from the brake booster with accumulator pump assembly to the brake booster with master cylinder assembly.
Refer to PROCEDURE - Step 2 [12/2019 - 10/2021] , or refer to PROCEDURE - Step 2 [10/2021 - 11/2023] , or refer to PROCEDURE - Step 2 [11/2023 - ]
OK
There are no brake fluid leaks.
Result
Proceed to OK NG
Result:
OK
REPLACE BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY AND BRAKE BOOSTER WITH ACCUMULATOR PUMP ASSEMBLY
for Brake Booster with Master Cylinder Assembly: Refer to REMOVAL [12/2019 - 10/2022] , or refer to REMOVAL [10/2022 - 11/2023] , or refer to REMOVAL [11/2023 - ]
for Brake Booster with Accumulator Pump Assembly: Refer to REMOVAL [12/2019 - 10/2022] , or refer to REMOVAL [10/2022 - 11/2023] , or refer to REMOVAL [11/2023 - ]
Result:
NG
REPAIR MALFUNCTIONING PART
- Check for brake fluid leaks in the line from the brake booster with accumulator pump assembly to the brake booster with master cylinder assembly.