C1391

BRAKE CONTROL / DYNAMIC CONTROL SYSTEMS: ELECTRONICALLY CONTROLLED BRAKE SYSTEM: C1391/69: Accumulator Leak Malfunction
C1391/69 - Accumulator Leak Malfunction

DESCRIPTION

The DTC is stored if internal or external brake fluid leaks are detected due to improper sealing in the brake actuator (brake booster with master cylinder assembly) or brake booster pump assembly. Internal leaks are suspected if the pump motor operates frequently without braking.





INSPECTION PROCEDURE

NOTICE:
When replacing the brake actuator (brake booster with master cylinder assembly), perform initialization and calibration of the linear solenoid valve Initialization.

PROCEDURE

1. CHECK FOR FLUID LEAK

(a) 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.

(b) Check that the brakes are not dragging.

OK:

There are no fluid leaks or dragging.

NG -- REPAIR OR REPLACE APPLICABLE PART
OK -- Continue to next step.

2. RECONFIRM DTC

(a) Clear the DTCs Reading and Clearing Diagnostic Trouble Codes.

(b) Turn the power switch on (READY).

(c) Check if the same DTC is output Reading and Clearing Diagnostic Trouble Codes.

Result:





B -- REPLACE BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY Removal
A -- Continue to next step.

3. PERFORM ACTIVE TEST USING TECHSTREAM (SOLENOID VALVE)

(a) Turn the power switch off.

(b) Connect the Techstream to the DLC3.

(c) Turn the power switch on (IG).

(d) Select the Active Test on the Techstream Data List / Active Test.

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).

ABS/VSC/TRAC





*: Electronically Controlled Brake System

(e) Perform the Active Test of the solenoid using the Techstream.

(f) Select the Data List on the Techstream Data List / Active Test.

ABS/VSC/TRAC





(g) 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.

Result:





B -- REPLACE BRAKE BOOSTER PUMP ASSEMBLY Removal
A -- Continue to next step.

4. REPLACE BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY

(a) Replace the brake actuator (brake booster with master cylinder assembly) Removal.

NEXT -- REPLACE BRAKE BOOSTER PUMP ASSEMBLY Removal