NO.8 AUTO HOLD DOES NOT WORK [ELECTRONICALLY CONTROLLED BRAKE SYSTEM]

id040309898900

Troubleshooting item

Autohold does not work

Possible cause

•  Stuck AUTOHOLD switch in off position

•  Electrical supply unit (ESU) detects a malfunction.

•  Open circuit in AUTOHOLD switch signal circuit

•  Open circuit in AUTOHOLD switch ground circuit

Troubleshooting item	Autohold does not work
Possible cause	• Stuck AUTOHOLD switch in off position • Electrical supply unit (ESU) detects a malfunction. • Open circuit in AUTOHOLD switch signal circuit • Open circuit in AUTOHOLD switch ground circuit

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	CONFIRM ELECTRICAL SUPPLY UNIT DTC • Retrieve the electrical supply unit using the M-MDS. (See DTC INSPECTION.) • Are any DTCs present?	Yes	Go to the applicable DTC inspection. (See DTC TABLE [BODY CONTROL MODULE (BCM) (E)].)
2		No	Go to the next step.
3	INSPECT AUTOHOLD SWITCH • Inspect the AUTOHOLD switch. (See AUTO HOLD SWITCH INSPECTION.) • Is the AUTOHOLD switch normal?	Yes	Go to the next step.
3		No	Replace the AUTOHOLD 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 ground circuit for an open circuit. (See CIRCUIT INSPECTION.) • Is the circuit normal?	Yes	Go to the next step.
4		No	Repair or replace the malfunctioning location, and perform the repair completion verification.
5	INSPECT AUTOHOLD SWITCH SIGNAL CIRCUIT FOR OPEN CIRCUIT • Inspect the signal circuit for an open circuit. (See CIRCUIT INSPECTION.) • Is the circuit normal?	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. (See ELECTRONICALLY CONTROLLED BRAKE UNIT REMOVAL/INSTALLATION [R.H.D.].) (See ELECTRONICALLY CONTROLLED BRAKE UNIT REMOVAL/INSTALLATION [L.H.D.].) Perform the repair completion verification.
5		No	Repair or replace the malfunctioning location, 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 [(E)].) If the CAN communication is normal, perform the diagnosis from Step 1.