Dtc P0504 Brake Switch A / B Correlation

Engine Hybrid System. Hilux. Tgn26, 36 Kun25, 26, 35, 36 Ggn25
2Tr-Fe Engine Control. Hilux. Tgn26, 36 Kun25, 26, 35, 36 Ggn25

DESCRIPTION

WIRING DIAGRAM

INSPECTION PROCEDURE

READ VALUE USING INTELLIGENT TESTER (STOP LIGHT SWITCH)

INSPECT STOP LIGHT SWITCH ASSEMBLY (B+ VOLTAGE)

INSPECT STOP LIGHT SWITCH ASSEMBLY

INSPECT ECM (STP AND ST1- VOLTAGE)

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


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 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 stores the DTC.

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
Conditions (a), (b) and (c) continue for 0.5 seconds or more
(1 trip detection logic):
(a) Ignition switch is ON.
(b) Brake pedal is released.
(c) STP signal is OFF when the ST1- signal is OFF.
  1. Short in stop light switch signal circuit
  2. STOP fuse
  3. Stop light switch assembly
  4. ECM

WIRING DIAGRAM


Hilux. Tgn26, 36 Kun25, 26, 35, 36 Ggn25.2Tr-Fe Engine Control.Sfi System (W/ Secondary Air Injection System). Dtc P0504 Brake Switch A / B Correlation


INSPECTION PROCEDURE

NOTICE:
Inspect the fuses of circuits related to this system before performing the following inspection procedure.
HINT:
  1. Read freeze frame data using the intelligent tester. Freeze frame data records the engine condition 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.
  2. 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.READ VALUE USING INTELLIGENT TESTER (STOP LIGHT SWITCH)

  1. Connect the intelligent tester to the DLC3.

  1. Turn the ignition switch to ON.

  1. Turn the intelligent tester on.

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

  1. Read the value displayed on the intelligent tester.

    Standard:
    Condition
    		Specified Condition
    Brake pedal depressed
    		STP signal ON
    Brake pedal released
    		STP signal OFF


NG
Go to step 2
OK

CHECK FOR INTERMITTENT PROBLEMS (HILUX_TGN26 RM000000PDQ0UCX.html)

2.INSPECT STOP LIGHT SWITCH ASSEMBLY (B+ VOLTAGE)
Hilux. Tgn26, 36 Kun25, 26, 35, 36 Ggn25.2Tr-Fe Engine Control.Sfi System (W/ Secondary Air Injection System). Dtc P0504 Brake Switch A / B Correlation

  1. Disconnect the stop light switch connector.

  1. Measure the voltage according to the value(s) in the table below.

    Standard Voltage:
    Tester Connection
    		Condition
    		Specified Condition
    A24-2 - Body ground
    		Always
    		11 to 14 V
    A24-3 - Body ground
    		Ignition switch ON
    		11 to 14 V
    Text in Illustration
    *a
    		Front view of wire harness connector
    (to Stop Light Switch Assembly)


NG
REPAIR OR REPLACE HARNESS OR CONNECTOR (STOP LIGHT SWITCH - BATTERY, IGNITION SWITCH)
OK


3.INSPECT STOP LIGHT SWITCH ASSEMBLY

  1. Inspect the stop light switch assembly (HILUX_TGN26 RM0000018VE00SX_01_0001.html).



NG
REPLACE STOP LIGHT SWITCH ASSEMBLY (HILUX_TGN26 RM0000018VF00UX.html)
OK


4.INSPECT ECM (STP AND ST1- VOLTAGE)
Hilux. Tgn26, 36 Kun25, 26, 35, 36 Ggn25.2Tr-Fe Engine Control.Sfi System (W/ Secondary Air Injection System). Dtc P0504 Brake Switch A / B Correlation

  1. Disconnect the ECM connector.

  1. Turn the ignition switch to ON.

  1. Measure the voltage according to the value(s) in the table below.

    Standard Voltage:
    Tester Connection
    		Condition
    		Specified Condition
    G89-16 (ST1-) - Body ground
    		Brake pedal released
    		11 to 14 V
    Brake pedal depressed
    		0 to 3 V
    G88-4 (STP) - Body ground
    		Brake pedal released
    		0 to 3 V
    Brake pedal depressed
    		11 to 14 V
    Text in Illustration
    *a
    		Depressed
    *b
    		Released
    *c
    		Rear view of wire harness connector
    (to ECM)


NG
REPAIR OR REPLACE HARNESS OR CONNECTOR (ECM - STOP LIGHT SWITCH)
OK

REPLACE ECM (HILUX_TGN26 RM000000VW202LX.html)