DTC C1391: Abnormal Leak in Accumulator [02/2019 - 12/2021]: Procedure
- CHECK FOR FLUID LEAK
- Check that there are no fluid leaks in the brake lines between the brake actuator (brake booster with master cylinder assembly) and the wheel cylinders.
- Check that the brakes are not dragging.
OK
There are no fluid leaks or dragging.
Result
Proceed to OK NG
Result:
NG
REPAIR OR REPLACE APPLICABLE PART
Result:
OK
See step 2
- RECONFIRM DTC
- Clear the DTCs.
Refer to DTC CHECK / CLEAR [02/2019 - 12/2021]
Chassis > ABS/VSC/TRAC > Clear DTCs
- Turn the ignition switch off.
- Turn the ignition switch to ON (READY).
- Check if the same DTC is output.
Refer to DTC CHECK / CLEAR [02/2019 - 12/2021]
Chassis > ABS/VSC/TRAC > Trouble Codes
Result
Result Proceed to DTC C1391 is output. A DTC C1391 is not output. B
Result:
B
REPLACE BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY. Refer to REMOVAL [02/2019 - 10/2019] , or refer to REMOVAL [10/2019 - 08/2020] , or refer to REMOVAL [08/2020 - 12/2021]
Result:
A
See step 3
- Clear the DTCs.
- PERFORM ACTIVE TEST USING TECHSTREAM (SOLENOID VALVE)
- Turn the ignition switch off.
- Connect the Techstream to the DLC3.
- Turn the ignition switch to ON.
- Select the Active Test on the Techstream.
Refer to DATA LIST / ACTIVE TEST [02/2019 - 12/2021]
Chassis > ABS/VSC/TRAC > Active Test
Tester Display Measurement Item Control Range Diagnostic Note ECB Solenoid (SMC/SRC/SCC) Switching solenoid valve (SMC/SRC/SCC) Solenoid ON/OFF - Operation sound of solenoid (clicking sound) can be heard
- ECB: Electronically Controlled Brake System
Chassis > ABS/VSC/TRAC > Active Test
Tester Display ECB Solenoid (SMC/SRC/SCC) HINT:
The Active Test can be performed when the following conditions are met.
- ABS main relay is on.
- Shift lever is in P.
- Parking brake is applied.
- Vehicle speed is 0 km/h (0 mph).
- Perform the Active Test of the solenoid using the Techstream.
- Select the Data List on the Techstream.
Refer to DATA LIST / ACTIVE TEST [02/2019 - 12/2021]
Chassis > ABS/VSC/TRAC > Data List
Tester Display Measurement Item Range Normal Condition Diagnostic Note Wheel Cylinder Pressure Sensor Wheel cylinder pressure sensor Min.: 0.00 V, Max.: 5.00 V Brake pedal released: 0.10 to 0.90 V Reading increases when brake pedal is depressed Chassis > ABS/VSC/TRAC > Data List
Tester Display Wheel Cylinder Pressure Sensor - Check that the output value of the wheel cylinder pressure sensor does not increase.
OK
The output value of the wheel cylinder pressure sensor does not increase.
HINT:
If the output value increases, there may be brake fluid leaks in the brake actuator (brake booster with master cylinder assembly).
Result
Result Proceed to The output value of the wheel cylinder pressure sensor increases. A The output values of the wheel cylinder pressure sensor does not increase. B
Result:
B
REPLACE BRAKE BOOSTER PUMP ASSEMBLY. Refer to REMOVAL [11/2018 - ]
Result:
A
See step 4
- REPLACE BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY
- Replace the brake actuator (brake booster with master cylinder assembly).
Refer to REMOVAL [02/2019 - 10/2019] , or refer to REMOVAL [10/2019 - 08/2020] , or refer to REMOVAL [08/2020 - 12/2021]
Result
Proceed to NEXT
Result:
NEXT
REPLACE BRAKE BOOSTER PUMP ASSEMBLY. Refer to REMOVAL [02/2019 - 10/2019] , or refer to REMOVAL [10/2019 - 08/2020] , or refer to REMOVAL [08/2020 - 12/2021]
- Replace the brake actuator (brake booster with master cylinder assembly).