Accumulator Pressure Sensor Malfunction - Electronically Controlled Brake System

BRAKE CONTROL: ELECTRONICALLY CONTROLLED BRAKE SYSTEM: C1365/54: Accumulator Pressure Sensor Malfunction
C1365/54 - Accumulator Pressure Sensor Malfunction

DESCRIPTION

The accumulator pressure sensor is built into the brake actuator.

The skid control ECU detects the accumulator pressure from the data sent from the accumulator pressure sensor, and then runs and stops the pump motor by operating the motor relay.

DTCs may be output if the accumulator pressure drops due to frequent braking (this is not a malfunction).





WIRING DIAGRAM

Refer to DTCs C1246/46, C1281/81 and C1364/61 C1246.

INSPECTION PROCEDURE

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

PROCEDURE

1. CHECK HARNESS AND CONNECTOR (SKID CONTROL ECU - BRAKE ACTUATOR)

(a) Make sure that there is no looseness at the locking part and the connecting part of the connectors.





(b) Disconnect the A46 skid control ECU connector and the brake actuator connector.

(c) Measure the resistance according to the value(s) in the table below.

Standard Resistance:





Text in Illustration





NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.

2. INSPECT SKID CONTROL ECU (SENSOR OUTPUT)

(a) Reconnect the skid control ECU connector and the brake actuator connector.





(b) Turn the ignition switch to ON.

(c) Measure the voltage according to the value(s) in the table below.

Standard Voltage:





Text in Illustration





NG -- REPLACE SKID CONTROL ECU Removal
OK -- Continue to next step.

3. INSPECT SKID CONTROL ECU (SENSOR INPUT)

(a) Depress the brake pedal to operate the pump motor, and then check that the pump motor stops.





(b) Measure the voltage according to the value(s) in the table below.

NOTICE:
Do not depress the brake pedal until the pump motor stops and the voltage check is finished in order to maintain the accumulator pressure.

Standard Voltage:





Text in Illustration





NG -- REPLACE BRAKE ACTUATOR ASSEMBLY Removal
OK -- Continue to next step.

4. READ VALUE USING TECHSTREAM (ACCUMULATOR PRESSURE SENSOR)

(a) Turn the ignition switch off.

(b) Connect the Techstream to the DLC3.

(c) Turn the ignition switch to ON.

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

ABS/VSC/TRAC





(e) Wait for 30 seconds without operating the brake pedal. Then check the accumulator pressure sensor output value's change is within the specified range.

OK:

Accumulator pressure sensor output value's change is within 0.2 V.

NG -- REPLACE BRAKE ACTUATOR ASSEMBLY Removal
OK -- Continue to next step.

5. RECONFIRM DTC

(a) Turn the ignition switch off.

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

(c) Perform a road test.

(d) Check if the same DTC is recorded Reading and Clearing Diagnostic Trouble Codes.

Result:





B -- REPLACE SKID CONTROL ECU Removal

A -- CHECK FOR INTERMITTENT PROBLEMS How To Proceed With Troubleshooting