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

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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.

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

Signals
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)
  1. (a) Engine switch on (IG)
  2. (b) Brake pedal released
  3. (c) STP signal OFF when ST1- signal OFF
  1. Short in stop light switch signal circuit
  2. STOP fuse
  3. Stop light switch
  4. ECM

WIRING DIAGRAM


A147866E03


INSPECTION PROCEDURE

УКАЗАНИЕ:
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.

1.CHECK OPERATION OF STOP LIGHT

  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.INSPECT STOP LIGHT SWITCH ASSEMBLY
A107172E07

  1. Remove the stop light switch assembly.

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

    Standard Resistance:
    Tester Connection
    		Switch Condition
    		 Specified Condition
    1 - 2
    		Switch pin free
    		Below 1 Ω
    3 - 4
    		10 kΩ or higher
    1 - 2
    		Switch pin pushed in
    		10 kΩ or higher
    3 - 4
    		Below 1 Ω



NG
REPLACE STOP LIGHT SWITCH ASSEMBLY
OK


3.READ VALUE USING INTELLIGENT TESTER (STP SIGNAL AND ST1- VOLTAGE)
A150279E01

  1. Connect the intelligent tester to the DLC3.

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

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

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

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

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

    Standard Voltage:
    Tester Connection
    		Condition
    		Specified Condition
    A14-12 (ST1-) - E3-1 (E1)
    		Brake pedal depressed
    		Below 1.5 V
    Brake pedal released
    		7.5 to 14 V



OK
CHECK FOR INTERMITTENT PROBLEMS (Нажмите здесь)
NG


4.CHECK HARNESS AND CONNECTOR (STOP LIGHT SWITCH - ECM)
A150335E01

  1. Disconnect the A35 stop light switch connector.

  1. Disconnect the A14 ECM connector.

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

    Standard Resistance (Check for open):
    Tester Connection
    		Condition
    		Specified Condition
    A35-1 (Stop light switch) - A14-13 (STP)
    		Always
    		Below 1 Ω
    A35-4 (Stop light switch) - A14-12 (ST1-)
    		Always

    Standard Resistance (Check for short):
    Tester Connection
    		Condition
    		Specified Condition
    A35-1 (Stop light switch) or A14-13 (STP) - Body ground
    		Always
    		10 kΩ or higher
    A35-4 (Stop light switch) or A14-12 (ST1-) - Body ground
    		Always



NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

REPLACE ECM (Нажмите здесь)