Diagnostic trouble code P0504 P0724 4GR-FSE Engine

Description

Wiring diagram

Inspection procedure

CHECK STOP LIGHT (STOP LIGHT OPERATION)

READ VALUE OF INTELLIGENT TESTER (STP SIGNAL AND ST1 - VOLTAGE)

INSPECT STOP LIGHT SWITCH ASSEMBLY

CHECK ECM (STP, ST1 - VOLTAGE)

DTC P0504 Brake Switch "A" / "B" Correlation

DTC P0724 Brake Switch "B" Circuit High

Description

The stop light switch is a duplex system that transmits two signals: STP and ST1-. These two signals are used by the ECM to monitor whether or not the brake system is working properly. If the signals, which indicate the brake pedal is being depressed and released, are detected simultaneously, the ECM interprets this as a malfunction in the stop light switch and sets the DTC.  

HINT:

The normal conditions are as shown in the table below. The signals can be read using an intelligent tester.

Signal	Brake Pedal Released	In Transition	Brake Pedal Depressed
STP	OFF	ON	ON
ST1-	ON	ON	OFF

DTC No.	DTC Detection Condition	Trouble Area
P0504	Conditions (a), (b) and (c) continue for 0.5 seconds or more (1 trip detection logic): (a) Engine switch on (IG) (b) Brake pedal released (c) STP signal OFF when ST1- signal OFF	Short in stop light switch signal circuit Stop light switch ECM
P0724	The stop light switch remains ON even when the vehicle is driven in a STOP (less than 3 km/h (2 mph)) and GO (30 km/h (19 mph) or more) fashion 5 times. (2 trip detection logic)	Short in stop light switch signal circuit Stop light switch ECM

Wiring diagram

Inspection procedure

HINT:

Read freeze frame data using the intelligent tester. Freeze frame data records the engine conditions when malfunctions are detected. When troubleshooting, freeze frame data can help determine if the vehicle was running or stopped, if the engine was warmed up or not, if the air-fuel ratio was lean or rich, and other data from the time the malfunction occurred .

 

1.CHECK STOP LIGHT (STOP LIGHT OPERATION)

1. Check whether the stop lights turn on and off normally when the brake pedal is depressed and released.

   OK:

   Stop lights turn ON when brake pedal is depressed.

NG	REPAIR OR REPLACE STOP LIGHT SWITCH CIRCUIT

OK

2.READ VALUE OF INTELLIGENT TESTER (STP SIGNAL AND ST1 - VOLTAGE)

1. Connect the intelligent tester to the DLC3.

2. Turn the engine switch on (IG) and turn the tester ON.

3. Enter the following menus: Power train / Engine / Data List / Stop Light Switch.

4. Check the STP signal when the brake pedal is depressed and released.

   OK:

   Brake Pedal Operation	Specified Condition
   Depressed	STP signal ON
   Released	STP signal OFF

5. Measure the voltage of the A5 and E4 ECM connectors.

Standard voltage:

Tester Connection	Brake Pedal Operation	Specified Condition
ST1- (A5-8) - E1 (E4-7)	Depressed	Below 1.5 V
ST1- (A5-8) - E1 (E4-7)	Released	7.5 to 14 V

OK	CHECK FOR INTERMITTENT PROBLEMS

NG

3.INSPECT STOP LIGHT SWITCH ASSEMBLY

1. Remove the stop light switch assembly.

2. Measure the resistance of the stop light switch.

   Standard resistance:

   Switch Position	Tester Connection	Specified Condition
   Switch pin free	1 - 2	Below 1 ?
   Switch pin free	3 - 4	10 k? or higher
   Switch pin pushed in	1 - 2	10 k? or higher
   Switch pin pushed in	3 - 4	Below 1 ?

3. Reinstall the stop light switch assembly.

NG	REPLACE STOP LIGHT SWITCH ASSEMBLY

OK

4.CHECK ECM (STP, ST1 - VOLTAGE)

1. Disconnect the A5 and A6 ECM connectors.

2. Measure the voltage of the A5 and A6 ECM connectors.

Standard voltage:

Tester Connection	Brake Pedal Operation	Specified Condition
STP (A6-4) - Body ground	Depressed	9 to 14 V
STP (A6-4) - Body ground	Released	0 to 3 V
ST1- (A5-8) - Body ground	Depressed	0 to 3 V
ST1- (A5-8) - Body ground	Released	9 to 14 V

NG	REPAIR OR REPLACE HARNESS OR CONNECTOR

OK
REPLACE ECM