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DTC C0040:64 [ELECTRONICALLY CONTROLLED BRAKE UNIT]

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Outline

System malfunction location	Brake switch
Detection condition	Note •  There are 2 types of brake switch signals as follows. ―  Brake switch No.1 signal received from electrical supply unit (ESU) ―  Brake switch No.2 signal received via CAN communication going through body control module (BCM) from PCM •  The electronically controlled brake unit detects any of the following conditions. ―  While driving at vehicle speed exceeding 20 km/h {12 mph}, brake switch No.1 signal is on for a continuous 6 min or more ―  While driving at vehicle speed exceeding 40 km/h {25 mph}, brake switch No.1 signal does not change from off to on even though there are 4 instances of vehicle speed decelerating to less than 3 km/h {2 mph}. ―  Brake light switch No.1 signal does not change from off to on even though brake fluid pressure sensor signal (master cylinder side) or stroke sensor signal reaches specification
Fail-safe	Refer to “DTC Table” and “Fail-safe Function Malfunction Contents Table”. (See DTC TABLE [ELECTRONICALLY CONTROLLED BRAKE UNIT].)
Possible cause	•  Brake switch connector or terminal malfunction •  Brake switch malfunction •  Short to ground or open circuit in brake switch power supply circuit •  Electrical supply unit (ESU) connector or terminals malfunction •  Short to power supply in brake switch signal circuit •  Short to ground in brake switch signal circuit •  Open circuit in brake switch signal circuit •  Electronically controlled brake unit connector or terminals malfunction •  Short to ground in electrical supply unit (ESU) brake signal circuit •  Short to power supply in electrical supply unit (ESU) brake signal circuit •  Open circuit in electrical supply unit (ESU) brake signal circuit •  Electrical supply unit (ESU) malfunction •  Electronically controlled brake unit malfunction

Diagnostic Procedure

Step	Inspection	Results	Action
1	DETERMINE MALFUNCTIONING LOCATION •  Perform the PID/data monitor inspection and display the following item. (See PID/DATA MONITOR INSPECTION.) (See PID/DATA MONITOR TABLE [ELECTRICAL SUPPLY UNIT (ESU) (E)].) Electrical supply unit (ESU) ―  BRK_SW •  Does the monitor value switch correctly in conjunction with the brake pedal depression/release?	Yes	Go to the next step.
		No	Go to Step 3.
2	INSPECT ELECTRICAL SUPPLY UNIT (ESU) CONNECTOR FOR MALFUNCTION •  Inspect the applicable connector and terminal. (See CONNECTOR INSPECTION.) •  Are the connector and terminal normal?	Yes	Go to Step 10.
		No	Repair or replace the malfunctioning location and perform the repair completion verification.
3	INSPECT BRAKE SWITCH CONNECTOR FOR MALFUNCTION •  Inspect the applicable connector and terminal. (See CONNECTOR INSPECTION.) •  Are the connector and terminal normal?	Yes	Go to the next step.
		No	Repair or replace the malfunctioning location and perform the repair completion verification.
4	INSPECT BRAKE SWITCH FOR MALFUNCTION •  Inspect the applicable part. (See BRAKE SWITCH INSPECTION.) •  Is the part normal?	Yes	Go to the next step.
		No	Repair or replace the malfunctioning location and perform the repair completion verification. (See BRAKE PEDAL REMOVAL/INSTALLATION [L.H.D. (E)].) (See BRAKE PEDAL REMOVAL/INSTALLATION [R.H.D.].)
5	INSPECT BRAKE SWITCH POWER SUPPLY CIRCUIT FOR SHORT TO GROUND AND OPEN CIRCUIT •  Inspect the power supply circuit for an open circuit and short to ground. (See CIRCUIT INSPECTION.) •  Is the circuit normal?	Yes	Go to the next step.
		No	Repair or replace the malfunctioning location and perform the repair completion verification.
6	INSPECT ELECTRICAL SUPPLY UNIT (ESU) CONNECTOR FOR MALFUNCTION •  Inspect the applicable connector and terminal. (See CONNECTOR INSPECTION.) •  Are the connector and terminal normal?	Yes	Go to the next step.
		No	Repair or replace the malfunctioning location and perform the repair completion verification.
7	INSPECT BRAKE SWITCH SIGNAL CIRCUIT FOR SHORT TO POWER SUPPLY •  Inspect the applicable circuit for a short to power supply. (See CIRCUIT INSPECTION.) •  Is the circuit normal?	Yes	Go to the next step.
		No	Repair or replace the malfunctioning location and perform the repair completion verification.
8	INSPECT BRAKE SWITCH SIGNAL CIRCUIT FOR SHORT TO GROUND •  Inspect the applicable circuit for a short to ground. (See CIRCUIT INSPECTION.) •  Is the circuit normal?	Yes	Go to the next step.
		No	Repair or replace the malfunctioning location and perform the repair completion verification.
9	INSPECT BRAKE SWITCH SIGNAL CIRCUIT FOR OPEN CIRCUIT •  Inspect the applicable circuit for an open circuit. (See CIRCUIT INSPECTION.) •  Is the circuit normal?	Yes	Go to the next step.
		No	Repair or replace the malfunctioning location and perform the repair completion verification.
10	INSPECT ELECTRONICALLY CONTROLLED BRAKE UNIT CONNECTOR FOR MALFUNCTION •  Inspect the applicable connector and terminal. (See CONNECTOR INSPECTION.) •  Are the connector and terminal normal?	Yes	Go to the next step.
		No	Repair or replace the malfunctioning location and perform the repair completion verification.
11	INSPECT ELECTRICAL SUPPLY UNIT (ESU) BRAKE SIGNAL CIRCUIT FOR SHORT TO GROUND •  Inspect the applicable circuit for a short to ground. (See CIRCUIT INSPECTION.) •  Is the circuit normal?	Yes	Go to the next step.
		No	Repair or replace the malfunctioning location and perform the repair completion verification.
12	INSPECT ELECTRICAL SUPPLY UNIT (ESU) BRAKE SIGNAL CIRCUIT FOR SHORT TO POWER SUPPLY •  Inspect the applicable circuit for a short to power supply. (See CIRCUIT INSPECTION.) •  Is the circuit normal?	Yes	Go to the next step.
		No	Repair or replace the malfunctioning location and perform the repair completion verification.
13	INSPECT ELECTRICAL SUPPLY UNIT (ESU) BRAKE SIGNAL CIRCUIT FOR OPEN CIRCUIT •  Inspect the applicable circuit for open circuit. (See CIRCUIT INSPECTION.) •  Is the circuit normal?	Yes	Go to the next step.
		No	Repair or replace the malfunctioning location and perform the repair completion verification.
14	INSPECT ELECTRICAL SUPPLY UNIT (ESU) FOR MALFUNCTION •  Install/connect the part removed/disconnected during the troubleshooting procedure. •  Clear the DTC recorded in the memory. (See CLEARING DTC.) •  Measure the voltage at electrical supply unit (ESU) terminal 3L (vehicle wiring harness side) according to the brake pedal operation and verify if it changes as follows. ―  Brake pedal released: 1.0 V or less ―  Brake pedal depressed: B+ •  Does the voltage change according to the brake pedal operation?	Yes	Go to the next step.
		No	Repair or replace the malfunctioning location and perform the repair completion verification. (See ELECTRICAL SUPPLY UNIT (ESU) REMOVAL/INSTALLATION.)
Repair completion verification 1	VERIFY THAT VEHICLE IS REPAIRED •  Install/connect the part removed/disconnected during the troubleshooting procedure. •  Clear the DTC recorded in the memory. (See CLEARING DTC.) •  Drive at a vehicle speed exceeding 40 km/h {25 mph} and repeatedly stop the vehicle 4 or 5 times. •  Drive at a vehicle speed exceeding 20 km/h {12 mph} for 6 min or more. •  Perform the DTC inspection for the electronically controlled brake unit. (See DTC INSPECTION.) •  Is the same Pending DTC present?	Yes	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 [(E)].) If the CAN communication is normal, perform the diagnosis from Step 1. •  If the malfunction recurs, replace the electronically controlled brake unit, then go to the next step. (See ELECTRONICALLY CONTROLLED BRAKE UNIT REMOVAL/INSTALLATION [L.H.D.].) (See ELECTRONICALLY CONTROLLED BRAKE UNIT REMOVAL/INSTALLATION [R.H.D.].)
		No	Go to the next step.
Repair completion verification 2	VERIFY IF OTHER DTCs DISPLAYED •  Perform the DTC inspection. (See DTC INSPECTION.) •  Are any DTCs displayed?	Yes	Repair the malfunctioning location according to the applicable DTC troubleshooting.
		No	DTC troubleshooting completed.