C1391

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

DESCRIPTION

The DTC is stored if a brake fluid, internal or other leak is detected due to improper sealing in the brake actuator or brake accumulator pump. Internal leakage is suspected if the pump motor operates frequently without braking.





INSPECTION PROCEDURE

NOTICE:
When replacing the skid control ECU or brake actuator, perform initialization of linear solenoid valve and calibration Initialization.

PROCEDURE

1. CHECK BRAKE FLUID LEAKAGE

(a) Check that there is no fluid leakage in the brake line between the brake actuator and the wheel cylinder which is the cause of DTCs.





(b) Check that the brake is not dragging.

OK:

There is no fluid leakage or dragging.

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

2. CHECK DTC

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

(b) Turn the engine switch OFF.

(c) Turn the engine switch ON (IG).

(d) Check if the same DTC C1391 is recorded.

Result





B -- REPLACE BRAKE ACTUATOR Removal
A -- Continue to next step.

3. PERFORM ACTIVE TEST USING TECHSTREAM (SMC1, SMC2, SLRRR, AND SLRRL)

(a) Connect the Techstream to the DLC3.

(b) Turn the engine switch ON (IG).

(c) Turn the Techstream main switch on.

(d) Select the Active Test mode on the Techstream.

HINT
The Active Test can be performed when the following conditions are met.

- Main relay 1 and 2 are on.
- Shift lever is P position.
- Parking brake is on.
- Vehicle speed is 0 km/h (0 mph).

ABS/VSC/TRAC





(e) Using the Techstream, turn SMC1, SMC2, SLRRR, or SLRRL ON.





(f) Check that each wheel cylinder's output value does not increase.

OK:

Each wheel cylinder's output value does not increase.

HINT
If any of wheel cylinder's output value increases, there may be a brake fluid leak in the brake actuator.

Result





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

4. REPLACE BRAKE ACTUATOR

Replace the brake actuator Removal.

NEXT -- REPLACE BRAKE ACCUMULATOR PUMP Removal