Dtc P0504/51 Brake Switch A / B Correlation


DESCRIPTION

WIRING DIAGRAM

INSPECTION PROCEDURE

When using intelligent tester:

CHECK STOP LIGHT (OPERATION)

READ DATA LIST (STP SIGNAL, ST1- VOLTAGE)

INSPECT STOP LIGHT SWITCH ASSEMBLY

CHECK HARNESS AND CONNECTOR (STOP LIGHT SWITCH - ECM)

When not using intelligent tester:

CHECK STOP LIGHT (OPERATION)

CHECK ECM (STP, ST1- VOLTAGE)

INSPECT STOP LIGHT SWITCH ASSEMBLY

CHECK HARNESS AND CONNECTOR (STOP LIGHT SWITCH - ECM)

DTC P0504/51 Brake Switch "A" / "B" Correlation


DESCRIPTION

In this system, the signals of the stop light switch's duplex system (STP and ST1-) are used to judge whether the brake system is abnormal or not. When the signals of depressing and releasing the brake pedal are detected simultaneously, the ECM interprets this as a malfunction of the stop light switch.

HINT:
The normal signal conditions are as shown in the table below.

Signal (ECM Terminal)
Brake Pedal Released
In Transition
Brake Pedal Depressed
STP
OFF
ON
ON
ST1-
ON
ON
OFF
  1. [OFF] denotes ground potential.
  2. [ON] denotes battery potential (+B).
  3. On the intelligent tester, the Data List items Stop Light Switch and ST1 are both ON when the brake pedal is depressed because the characteristics of ST1 indication are the opposite of the characteristics of Stop Light Switch indication.

DTC No.
DTC Detection Condition
Trouble Area
P0504/51
Conditions (a), (b) and (c) continue for 0.5 seconds or more:
  1. (a) Ignition switch ON
  2. (b) Brake pedal released
  3. (c) STP signal is OFF when ST1- signal is OFF
  1. Short in stop light switch signal circuit
  2. STOP fuse
  3. Stop light switch
  4. ECM

WIRING DIAGRAM


Toyota Fortuner. Ggn50, 60 Kun51, 61 Tgn51 Lan50.2Tr-Fe Engine Control System.Sfi System. Dtc P0504/51 Brake Switch A / B Correlation


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 moving or stationary, 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.

When using intelligent tester:

HINT:
Stop light switch conditions can be checked using the intelligent tester.
  1. Connect the intelligent tester to the DLC3.
  2. Turn the ignition switch to ON.
  3. Turn the intelligent tester on.
  4. Enter the following menus: Powertrain / Engine and ECT / Data List / All Data / Stop Light Switch and ST1.
  5. Check the Data List indication when the brake pedal is depressed and released.

    Brake Pedal Operation
    		Stop Light Switch
    		ST1
    Depressed
    		ON
    		ON
    Released
    		OFF
    		OFF
1.CHECK STOP LIGHT (OPERATION)

  1. Check that the stop lights turn ON and OFF when the brake pedal is depressed and released, respectively.

    OK:
    Stop lights turn ON and OFF when brake pedal is depressed and released, respectively.


NG
REPAIR OR REPLACE STOP LIGHT SWITCH CIRCUIT
OK


2.READ DATA LIST (STP SIGNAL, ST1- VOLTAGE)
Toyota Fortuner. Ggn50, 60 Kun51, 61 Tgn51 Lan50.2Tr-Fe Engine Control System.Sfi System. Dtc P0504/51 Brake Switch A / B Correlation

  1. Connect the intelligent tester to the DLC3.

  1. Turn the ignition switch ON and turn the intelligent tester ON.

  1. Enter the following menus: Powertrain / Engine and ECT / Data List / Stop Light Switch.

  1. Check the STP signal when depressing and releasing the brake pedal.

    OK:
    Brake Pedal Condition
    		Specified Condition
    Depressed
    		STP Signal ON
    Released
    		STP Signal OFF

  1. Measure the voltage of the ECM connectors.

    Standard voltage:
    Tester Connection
    		Brake Pedal Condition
    		Specified Condition
    E8-16 (ST1-) - E11-3 (E1)
    		Depressed
    		Below 1.5 V
    E8-16 (ST1-) - E11-3 (E1)
    		Released
    		7.5 to 14 V


OK
CHECK FOR INTERMITTENT PROBLEMS
NG


3.INSPECT STOP LIGHT SWITCH ASSEMBLY
Toyota Fortuner. Ggn50, 60 Kun51, 61 Tgn51 Lan50.2Tr-Fe Engine Control System.Sfi System. Dtc P0504/51 Brake Switch A / B Correlation

  1. Measure the resistance of the switch.

    Standard resistance:
    Tester Connection
    		Switch Condition
    		Specified Condition
    1 - 2
    		Pin not pushed
    		Below 1 Ω
    3 - 4
    		Pin not pushed
    		10 kΩ or higher
    1 - 2
    		Pin pushed
    		10 kΩ or higher
    3 - 4
    		Pin pushed
    		Below 1 Ω


NG
REPLACE STOP LIGHT SWITCH ASSEMBLY
OK


4.CHECK HARNESS AND CONNECTOR (STOP LIGHT SWITCH - ECM)
Toyota Fortuner. Ggn50, 60 Kun51, 61 Tgn51 Lan50.2Tr-Fe Engine Control System.Sfi System. Dtc P0504/51 Brake Switch A / B Correlation

  1. Disconnect the E8 and E9 ECM connectors.

  1. Disconnect the S14 stop light switch connector.

  1. Measure the resistance of the wire harness side connectors.

    Standard resistance:
    Tester Connection
    		Specified Condition
    S14-1 - E9-4 (STP)
    		Below 1 Ω
    S14-4 - E8-16 (ST1-)
    		Below 1 Ω
    S14-1 or E9-4 (STP) - Body ground
    		10 kΩ or higher
    S14-4 or E8-16 (ST1-) - Body ground
    		10 kΩ or higher


NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

REPLACE ECM


When not using intelligent tester:

1.CHECK STOP LIGHT (OPERATION)

  1. Check that the stop lights turn ON and OFF when the brake pedal is depressed and released, respectively.

    OK:
    Stop lights turn ON and OFF when brake pedal is depressed and released, respectively.


NG
REPAIR OR REPLACE STOP LIGHT SWITCH CIRCUIT
OK


2.CHECK ECM (STP, ST1- VOLTAGE)
Toyota Fortuner. Ggn50, 60 Kun51, 61 Tgn51 Lan50.2Tr-Fe Engine Control System.Sfi System. Dtc P0504/51 Brake Switch A / B Correlation

  1. Turn the ignition switch ON.

  1. Measure the voltage of the ECM connectors.

    Standard voltage:
    Tester Connection
    		Brake Pedal Condition
    		Specified Condition
    E9-4 (STP) - E11-3 (E1)
    		Depressed
    		7.5 to 14 V
    E9-4 (STP) - E11-3 (E1)
    		Released
    		Below 1.5 V
    E8-16 (ST1-) - E11-3 (E1)
    		Depressed
    		Below 1.5 V
    E8-16 (ST1-) - E11-3 (E1)
    		Released
    		7.5 to 14 V


OK
CHECK FOR INTERMITTENT PROBLEMS
NG


3.INSPECT STOP LIGHT SWITCH ASSEMBLY
Toyota Fortuner. Ggn50, 60 Kun51, 61 Tgn51 Lan50.2Tr-Fe Engine Control System.Sfi System. Dtc P0504/51 Brake Switch A / B Correlation

  1. Measure the resistance of the switch.

    Standard resistance:
    Tester Connection
    		Switch Condition
    		Specified Condition
    1 - 2
    		Pin not pushed
    		Below 1 Ω
    3 - 4
    		Pin not pushed
    		10 kΩ or higher
    1 - 2
    		Pin pushed
    		10 kΩ or higher
    3 - 4
    		Pin pushed
    		Below 1 Ω


NG
REPLACE STOP LIGHT SWITCH ASSEMBLY
OK


4.CHECK HARNESS AND CONNECTOR (STOP LIGHT SWITCH - ECM)
Toyota Fortuner. Ggn50, 60 Kun51, 61 Tgn51 Lan50.2Tr-Fe Engine Control System.Sfi System. Dtc P0504/51 Brake Switch A / B Correlation

  1. Disconnect the E8 and E9 ECM connectors.

  1. Disconnect the S14 stop light switch connector.

  1. Measure the resistance of the wire harness side connectors.

    Standard resistance:
    Tester Connection
    		Specified Condition
    S14-1 - E9-4 (STP)
    		Below 1 Ω
    S14-4 - E8-16 (ST1-)
    		Below 1 Ω
    S14-1 or E9-4 (STP) - Body ground
    		10 kΩ or higher
    S14-4 or E8-16 (ST1-) - Body ground
    		10 kΩ or higher


NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

REPLACE ECM