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

for Preparation Click here


DESCRIPTION

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:
Normal condition is shown in the table below.

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

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


WIRING DIAGRAM


A099785E01


INSPECTION PROCEDURE

HINT:
Read freeze frame data using the intelligent tester. Freeze frame data records the engine conditions when a malfunction is detected. When troubleshooting, freeze frame data can help determine if the vehicle was running or stopped, if the engine was warmed up or not, and other data from the time the malfunction occurred.

NOTICE:
If the ECM is replaced, the new ECM needs initialization (Click here).


When using intelligent tester:

1.CHECK STOP LIGHT (OPERATION)

  1. Check if the stop lights turn ON and OFF normally when the brake pedal is depressed and released.

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



NG
REPAIR OR REPLACE STOP LIGHT SWITCH CIRCUIT
OK


2.READ DATA LIST (STP SIGNAL, ST1 - VOLTAGE)
A080995E03

  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 / Data List / Stop Light Switch.

  1. Check the result.

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

  1. Measure the voltage of the ECM connectors.

    Standard voltage:
    Tester Connection
    		Brake Pedal
    		Specified Condition
    E6-14 (ST1-) - E7-7 (E1)
    		Depressed
    		Below 1.5 V
    E6-14 (ST1-) - E7-7 (E1)
    		Released
    		7.5 to 14 V



OK
CHECK FOR INTERMITTENT PROBLEMS
NG


3.INSPECT STOP LIGHT SWITCH ASSEMBLY
A072924E08

  1. Remove the stop light switch.

  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 WIRE HARNESS (STOP LIGHT SWITCH - ECM)
A099860E02

  1. Disconnect the S14 stop light switch connector.

  1. Disconnect the E6 ECM connector.

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

    Standard:
    Tester Connection
    		Specified Condition
    S14-1 - E6-15 (STP)
    		Below 1 Ω
    S14-4 - E6-14 (ST1-)
    		Below 1 Ω
    S14-1 or E6-15 (STP) - Body ground
    		10 kΩ or higher
    S14-4 or E6-14 (ST1-) - Body ground
    		10 kΩ or higher



NG
REPAIR OR REPLACE HARNESS AND CONNECTOR
OK

REPLACE ECM 


When not using intelligent tester:

1.CHECK STOP LIGHT (OPERATION)

  1. Check if the stop lights turn ON and OFF normally when the brake pedal is depressed and released.

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



NG
REPAIR OR REPLACE STOP LIGHT SWITCH CIRCUIT
OK


2.CHECK ECM (STP, ST1- VOLTAGE)
A080995E04

  1. Turn the ignition switch ON.

  1. Measure the voltage of the ECM connectors.

    Standard voltage:
    Tester Connection
    		Brake Pedal Condition
    		Specified Condition
    E6-15 (STP) - E7-7 (E1)
    		Depressed
    		7.5 to 14 V
    E6-15 (STP) - E7-7 (E1)
    		Released
    		Below 1.5 V
    E6-14 (ST1-) - E7-7 (E1)
    		Depressed
    		Below 1.5 V
    E6-14 (ST1-) - E7-7 (E1)
    		Released
    		7.5 to 14 V



OK
CHECK FOR INTERMITTENT PROBLEMS
NG


3.INSPECT STOP LIGHT SWITCH ASSEMBLY
A072924E08

  1. Remove the stop light switch.

  1. Measure the resistance of the switch.

    Standard:
    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 WIRE HARNESS (STOP LIGHT SWITCH - ECM)
A099860E02

  1. Disconnect the S14 switch connector.

  1. Disconnect the E6 ECM connector.

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

    Standard resistance:
    Tester Connection
    		Specified Condition
    S14-1 - E6-15 (STP)
    		Below 1 Ω
    S14-4 - E6-14 (ST1-)
    		Below 1 Ω
    S14-1 or E6-15 (STP) - Body ground
    		10 kΩ or higher
    S14-4 or E6-14 (ST1-) - Body ground
    		10 kΩ or higher



NG
REPAIR OR REPLACE HARNESS AND CONNECTOR
OK

REPLACE ECM