AUTOHOLD DOES NOT OPERATE [ELECTRONICALLY CONTROLLED BRAKE SYSTEM]

id040309071000

Outline

Description

AUTOHOLD does not operate

Possible cause

•  AUTOHOLD switch is stuck off

•  Electrical supply unit (ESU) malfunction

•  Open circuit in AUTOHOLD switch signal circuit

•  Open circuit in AUTOHOLD switch ground circuit

Description	AUTOHOLD does not operate
Possible cause	• AUTOHOLD switch is stuck off • Electrical supply unit (ESU) malfunction • Open circuit in AUTOHOLD switch signal circuit • Open circuit in AUTOHOLD switch ground circuit

Diagnostic Procedure

Step

Inspection

Results

Action

1

VERIFY ELECTRONICALLY CONTROLLED BRAKE UNIT DTCs

•  Verify the electronically controlled brake unit DTCs.
(See DTC INSPECTION.)

•  Is a DTC displayed?

Yes

Repair the malfunctioning location according to the applicable DTC troubleshooting.

(See DTC TABLE [ELECTRONICALLY CONTROLLED BRAKE UNIT].)

No

Go to the next step.

2

INSPECT ELECTRICAL SUPPLY UNIT (ESU) FOR MALFUNCTION

•  Perform the DTC inspection for the body control module (BCM).
(See DTC INSPECTION.)

•  Is an electrical supply unit (ESU) related DTC displayed?

Yes

Repair the malfunctioning location according to the applicable DTC troubleshooting.

No

Go to the next step.

3

INSPECT AUTOHOLD SWITCH FOR MALFUNCTION

•  Inspect the applicable part.
(See AUTOHOLD SWITCH INSPECTION.)

•  Is the AUTOHOLD switch normal?

Yes

Go to the next step.

No

Replace the electric parking brake switch and perform the repair completion verification.

(See ELECTRIC PARKING BRAKE SWITCH REMOVAL/INSTALLATION.)

4

INSPECT AUTOHOLD SWITCH GROUND 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.

5

INSPECT AUTOHOLD SWITCH SIGNAL CIRCUIT FOR OPEN CIRCUIT

•  Inspect the applicable circuit for an open circuit.
(See CIRCUIT INSPECTION.)

•  Is the circuit normal?

Yes

Refer to the CAN (controller area network) malfunction diagnosis flow to inspect for a CAN communication error.

(See CONTROLLER AREA NETWORK (CAN) MALFUNCTION DIAGNOSIS FLOW [L.H.D. (E)].)

(See CONTROLLER AREA NETWORK (CAN) MALFUNCTION DIAGNOSIS FLOW [R.H.D.].)

If the CAN communication is normal, perform the diagnosis from Step 1.

•  If the malfunction has not been resolved, replace the electronically controlled brake unit.
(See ELECTRONICALLY CONTROLLED BRAKE UNIT REMOVAL/INSTALLATION [L.H.D.].)

(See ELECTRONICALLY CONTROLLED BRAKE UNIT REMOVAL/INSTALLATION [R.H.D.].)

Perform the repair completion verification.

No

Repair or replace the malfunctioning location and perform the repair completion verification.

Repair completion verification

VERIFY IF MALFUNCTION CAUSE IS CORRECTED

•  Install/connect the part removed/disconnected during the troubleshooting procedure.

•  Has the malfunction symptom been eliminated?

Yes

Complete the symptom troubleshooting.

Explain repair contents to customer.

No

Refer to the CAN (controller area network) malfunction diagnosis flow to inspect for a CAN communication error.

(See CONTROLLER AREA NETWORK (CAN) MALFUNCTION DIAGNOSIS FLOW [L.H.D. (E)].)

(See CONTROLLER AREA NETWORK (CAN) MALFUNCTION DIAGNOSIS FLOW [R.H.D.].)

If the CAN communication is normal, perform the diagnosis from Step 1.

Step	Inspection	Results	Action
1	VERIFY ELECTRONICALLY CONTROLLED BRAKE UNIT DTCs • Verify the electronically controlled brake unit DTCs. (See DTC INSPECTION.) • Is a DTC displayed?	Yes	Repair the malfunctioning location according to the applicable DTC troubleshooting. (See DTC TABLE [ELECTRONICALLY CONTROLLED BRAKE UNIT].)
		No	Go to the next step.
2	INSPECT ELECTRICAL SUPPLY UNIT (ESU) FOR MALFUNCTION • Perform the DTC inspection for the body control module (BCM). (See DTC INSPECTION.) • Is an electrical supply unit (ESU) related DTC displayed?	Yes	Repair the malfunctioning location according to the applicable DTC troubleshooting.
		No	Go to the next step.
3	INSPECT AUTOHOLD SWITCH FOR MALFUNCTION • Inspect the applicable part. (See AUTOHOLD SWITCH INSPECTION.) • Is the AUTOHOLD switch normal?	Yes	Go to the next step.
		No	Replace the electric parking brake switch and perform the repair completion verification. (See ELECTRIC PARKING BRAKE SWITCH REMOVAL/INSTALLATION.)
4	INSPECT AUTOHOLD SWITCH GROUND 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.
5	INSPECT AUTOHOLD SWITCH SIGNAL CIRCUIT FOR OPEN CIRCUIT • Inspect the applicable circuit for an open circuit. (See CIRCUIT INSPECTION.) • Is the circuit normal?	Yes	Refer to the CAN (controller area network) malfunction diagnosis flow to inspect for a CAN communication error. (See CONTROLLER AREA NETWORK (CAN) MALFUNCTION DIAGNOSIS FLOW [L.H.D. (E)].) (See CONTROLLER AREA NETWORK (CAN) MALFUNCTION DIAGNOSIS FLOW [R.H.D.].) If the CAN communication is normal, perform the diagnosis from Step 1. • If the malfunction has not been resolved, replace the electronically controlled brake unit. (See ELECTRONICALLY CONTROLLED BRAKE UNIT REMOVAL/INSTALLATION [L.H.D.].) (See ELECTRONICALLY CONTROLLED BRAKE UNIT REMOVAL/INSTALLATION [R.H.D.].) Perform the repair completion verification.
		No	Repair or replace the malfunctioning location and perform the repair completion verification.
Repair completion verification	VERIFY IF MALFUNCTION CAUSE IS CORRECTED • Install/connect the part removed/disconnected during the troubleshooting procedure. • Has the malfunction symptom been eliminated?	Yes	Complete the symptom troubleshooting. Explain repair contents to customer.
		No	Refer to the CAN (controller area network) malfunction diagnosis flow to inspect for a CAN communication error. (See CONTROLLER AREA NETWORK (CAN) MALFUNCTION DIAGNOSIS FLOW [L.H.D. (E)].) (See CONTROLLER AREA NETWORK (CAN) MALFUNCTION DIAGNOSIS FLOW [R.H.D.].) If the CAN communication is normal, perform the diagnosis from Step 1.