Subaru Legacy BN/BS (2015-2019) Service Manual: Dtc p0724 brake switch "b" circuit high

Subaru Legacy BN/BS (2015-2019) Service Manual / Continuously variable transmission (diagnostics) / Diagnostic procedure with diagnostic trouble code (dtc) / Dtc p0724 brake switch "b" circuit high

DTC DETECTING CONDITION:

Immediately at fault recognition

TROUBLE SYMPTOM:

Gear is not shifted down when climbing a hill or driving down a hill.

WIRING DIAGRAM:

• ENGINE TYPE FB

Stop light system Stop Light System

• ENGINE TYPE EZ

Stop light system Stop Light System

STEP	CHECK	YES	NO
1.CHECK STOP LIGHT SWITCH. 1) Turn the ignition switch to OFF. 2) Disconnect the stop light switch connector. 3) Measure the resistance between stop light switch connectors. Connector & terminal (B65) No. 1 — No. 2:	Is the resistance 1 M- or more-	Diagnostic Procedure with Diagnostic Trouble Code (DTC) > DTC P0724 BRAKE SWITCH "B" CIRCUIT HIGH	Replace the stop light switch. Stop Light Switch
2.CHECK HARNESS. 1) Disconnect the TCM connector. 2) Turn the ignition switch to ON. 3) Measure the voltage between TCM connector and chassis ground. Connector & terminal ENGINE TYPE FB (T10) No. 29 (+) — Chassis ground (−): ENGINE TYPE EZ (B54) No. 29 (+) — Chassis ground (−):	Is the voltage 10 V or more-	Repair the short circuit of harness.	Diagnostic Procedure with Diagnostic Trouble Code (DTC) > DTC P0724 BRAKE SWITCH "B" CIRCUIT HIGH
3.CHECK INPUT SIGNAL FOR TCM. 1) Connect the TCM and stop light switch connector. 2) Turn the ignition switch to ON. 3) Read the data of «Stop Light Switch» using Subaru Select Monitor.	Is “OFF” displayed-	Current condition is normal. Check for poor contact in connectors or harnesses, and repair the defective part.	Diagnostic Procedure with Diagnostic Trouble Code (DTC) > DTC P0724 BRAKE SWITCH "B" CIRCUIT HIGH
4.CHECK FOR POOR CONTACT.	Is there poor contact of input signal of stop light switch-	Repair the poor contact.	Replace the TCM. Transmission Control Module (TCM) Transmission Control Module (TCM)

1. OUTLINE OF DIAGNOSIS

• Detect the brake signal stuck to ON.

• Judge as NG if a predetermined number of acceleration occurs while the cruise control is set to OFF and the brake is ON.

2. EXECUTION CONDITION

Secondary Parameters	Execution condition
Cruise control	OFF
Malfunctions listed on the right column are not detected:	P0717, P0720

3. DIAGNOSTIC METHOD

If the duration of time while the following conditions are met is longer than the time indicated, judge as NG.

Judgment Value

Malfunction Criteria	Threshold Value
Number of times that vehicle speed changes from 1 km/h to 30 km/h while the brake SW is ON	> 10 count

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Other materials:

Inspection
1. BASIC INSPECTIONBefore performing the diagnosis, check the following items which may cause problems relating the wiper or light.1. Check the battery. Battery > INSPECTION Battery > INSPECTION2. Check the relay and fuse condition. Relay and Fuse3. Check the connecting condition of harness and h ...