BRAKE PEDAL MOVES DOWN (NO BRAKE FLUID LEAKAGE AND TRAPPED AIR) [ELECTRONICALLY CONTROLLED BRAKE SYSTEM]

id040309892900

Troubleshooting item

Brake pedal moves down (no brake fluid leakage and trapped air)

Possible cause

•  Electronically controlled brake unit detects a malfunction.

•  Stroke simulator malfunction.

•  Stroke sensor malfunction.

•  Liner actuator malfunction.

Note

•  If a malfunction occurs in the electronically controlled brake unit and all the solenoid valves turn off, the brake pedal operation feel may change and worsened braking performance may be felt.

•  The stroke simulator, stroke sensor, and the linear actuator are integrated in the electronically controlled brake unit.

System wiring diagram

Not applicable

Connector diagram

Not applicable

Troubleshooting item	Brake pedal moves down (no brake fluid leakage and trapped air)
Possible cause	• Electronically controlled brake unit detects a malfunction. • Stroke simulator malfunction. • Stroke sensor malfunction. • Liner actuator malfunction. Note • If a malfunction occurs in the electronically controlled brake unit and all the solenoid valves turn off, the brake pedal operation feel may change and worsened braking performance may be felt. • The stroke simulator, stroke sensor, and the linear actuator are integrated in the electronically controlled brake unit.
System wiring diagram	Not applicable
Connector diagram	Not applicable

Diagnostic procedure

Step	Inspection	Results	Action
1	CONFIRM ELECTRONICALLY CONTROLLED BRAKE UNIT DTC • Retrieve the electronically controlled brake unit DTC using the M-MDS. (See DTC INSPECTION.) • Are any DTCs present?	Yes	Go to the applicable DTC inspection. (See DTC TABLE [ELECTRONICALLY CONTROLLED BRAKE UNIT].)
1		No	Go to the next step.
2	PERFORM BRAKE PEDAL INSPECTION • Are the brake pedal height, play, and the brake pedal-to-floor clearance normal? (See BRAKE PEDAL INSPECTION.)	Yes	Go to the next step.
2		No	Repair, replace, or adjust the related part according to the nature of the malfunction, and perform the repair completion verification.
Repair completion verification	VERIFY THAT MALFUNCTION SYMPTOMS DO NOT RECUR AFTER REPAIR • Install/connect the part removed/disconnected during the troubleshooting procedure. • Has the malfunction symptom been eliminated?	Yes	Complete the symptom troubleshooting. Explain to the customer what has been repaired.
Repair completion verification		No	Refer to the controller area network (CAN) malfunction diagnosis flow to inspect for a CAN communication error. (See CONTROLLER AREA NETWORK (CAN) MALFUNCTION DIAGNOSIS FLOW.) If the CAN communication is normal, perform the diagnosis from Step 1.