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

for Preparation Click here


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 that 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 conditions are as shown in the table below.

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


P0504 
DTC Detection Drive Pattern
DTC Detection Condition
Trouble Area
Release and depress brake pedal with ignition switch ON.
  1. Conditions (a), (b) and (c) continue for 5.0 seconds or more:
    1. Ignition switch ON
    2. Brake pedal depressed
    3. STP signal off when ST1 signal off
  2. (2 trip detection logic)
  1. Short in stop light switch signal circuit
  2. Stop light switch
  3. ECM

Related Data List 
DTC No.
Data List
P0504
  1. Stop Light Switch

WIRING DIAGRAM


A199005E01


INSPECTION PROCEDURE

NOTICE:
  1. When replacing the ECM, the ECM needs Registration and Initialization (Click here).
  2. Inspect the fuse for circuits related to this system before performing the following inspection procedure.

HINT:
  1. When the ECM must be replaced, before replacing the ECM, perform the "Learning Values Save" function using the intelligent tester. Then after installing the new ECM, perform all of the initializations/registrations for the "Learning Values Write" function by following the instructions shown on the tester display.
  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 and turn the tester on.
    3. Enter the following menus: Powertrain / Engine and ECT / Data List / Stop Light Switch.
    4. Check Stop Light Switch when the brake pedal is depressed and released.

      Brake Pedal Operation
      		Specified Condition
      Depressed
      		ON
      Released
      		OFF

1.CHECK STOP LIGHT SWITCH ASSEMBLY (TERMINAL B VOLTAGE)


    A115660E07

  1. Disconnect the stop light switch connector.

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

    Standard Voltage:
    Tester Connection
    		Switch Condition
    		Specified Condition
    A27-2 - Body ground
    		Always
    		11 to 14 V
    A27-3 - Body ground
    		Ignition switch ON
    		11 to 14 V

    Text in Illustration 
    *1
    		Front view of wire harness connector
    (to Stop Light Switch)

  1. Reconnect the stop light switch connector.



NG
Go to step 6
OK


2.INSPECT STOP LIGHT SWITCH ASSEMBLY


    A199025E01

  1. Remove the stop light switch.

  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 not pushed
    		Below 1 Ω
    Switch pin pushed
    		10 kΩ or higher
    3 - 4
    		Switch pin not pushed
    		10 kΩ or higher
    Switch pin pushed
    		Below 1 Ω

  1. Reinstall the stop light switch.



NG
Go to step 5
OK


3.CHECK ECM (STP AND ST1- VOLTAGE)


    A157784E02

  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
    		Brake Pedal Condition
    		Specified Condition
    A19-28 (ST1-) - Body ground
    		Released
    		11 to 14 V
    Depressed
    		0 to 3 V
    A19-29 (STP) - Body ground
    		Released
    		0 to 3 V
    Depressed
    		11 to 14 V

  1. Reconnect the ECM connector.



NG
Go to step 6
OK


4.REPLACE ECM

  1. Replace the ECM (Click here).



NEXT
Go to step 7

5.REPLACE STOP LIGHT SWITCH ASSEMBLY

  1. Replace the stop light switch assembly (Click here).



NEXT
Go to step 7

6.REPAIR OR REPLACE HARNESS OR CONNECTOR

NEXT


7.CONFIRM WHETHER MALFUNCTION HAS BEEN SUCCESSFULLY REPAIRED

  1. Connect the intelligent tester to the DLC3.

  1. Clear the DTCs (Click here).

  1. Turn the ignition switch to ON.

  1. Depress the brake pedal for 10 seconds or more.

  1. Confirm that the DTC is not output again.


NEXT

END