C1256

BRAKE CONTROL: ELECTRONICALLY CONTROLLED BRAKE SYSTEM: C1256/57: Accumulator Low Pressure


DESCRIPTION

The accumulator pressure sensor is built into the actuator and detects the accumulator pressure.
The skid control ECU turns on the brake control warning light and sounds the skid control buzzer if it senses a decrease in the accumulator pressure.






WIRING DIAGRAM





INSPECTION PROCEDURE
NOTE: When replacing the skid control ECU or brake actuator assembly, perform initialization of linear solenoid valve and calibration Initialization.
HINT:
- When C1241/41, C1252/52 or C1253/53 is output together with C1256/57, inspect and repair the trouble areas indicated by C1241/41, C1252/52 or C1253/53 first.
- DTCs may be output if the accumulator pressure drops due to frequent braking (this is not a malfunction).

PROCEDURE

1. PROBLEM CHECK
(a) Ask the customer if frequent braking is performed when the brake control warning light comes on.
OK:





HINT: This DTC is output even if the accumulator pressure drops only temporarily due to frequent braking.

B -- END
A -- Continue to next step.
2. INSPECT BRAKE ACTUATOR ASSEMBLY





(a) Disconnect the brake actuator assembly connector.
(b) Measure the resistance according to the value(s) in the table below.
Resistance:






NG -- REPLACE BRAKE ACTUATOR ASSEMBLY
OK -- Continue to next step.
3. READ VALUE OF TECHSTREAM (ACCUMULATOR PRESSURE SENSOR)
(a) Connect Techstream to the DLC3.
(b) Turn the ignition switch on.
(c) Select the Data List mode on Techstream.

ABS / VSC / TRAC:





(d) Depress the brake pedal 4 or 5 times to operate the pump motor, and check the output value on Techstream with the motor stopped (not braking).
OK:
ACC pressure sensor's output voltage does not drop.
NG -- REPLACE BRAKE ACTUATOR ASSEMBLY
OK -- REPLACE SKID CONTROL ECU