Dtc P0504 Brake Switch A / B Correlation

Engine Hybrid System. Corolla. Zre142 Aze141
2Az-Fe Engine Control. Corolla. Zre142 Aze141

DESCRIPTION

WIRING DIAGRAM

INSPECTION PROCEDURE

INSPECT STOP LIGHT SWITCH (TERMINAL VOLTAGE)

INSPECT STOP LIGHT SWITCH

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 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 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 Techstream, both the Data List items Stop Light Switch and ST1 are ON when the brake pedal is depressed because the ST1 indication characteristic is opposite to the Stop Light Switch indication.

DTC No.
DTC Detection Condition
Trouble Area
P0504
Conditions (a) and (b) continue for 0.5 seconds or more
(1 trip detection logic):
(a) Ignition switch ON
(b) STP signal OFF when ST1- signal OFF
  1. Short in stop light switch signal circuit
  2. Stop light switch
  3. ECM

WIRING DIAGRAM


Corolla. Zre142 Aze141.2Az-Fe Engine Control.Sfi System. Dtc P0504 Brake Switch A / B Correlation


INSPECTION PROCEDURE

NOTICE:
Inspect the fuses for circuits related to this system before performing the following inspection procedure.
HINT:
  1. Read freeze frame data using the Techstream. The ECM records vehicle and driving condition information as freeze frame data the moment a DTC is stored. When troubleshooting, freeze frame data can be helpful in determining whether the vehicle was running or stopped, whether the engine was warmed up or not, whether the air fuel ratio was lean or rich, as well as other data recorded at the time of a malfunction.
  2. STP light switch conditions can be checked using the Techstream.
    1. Connect the Techstream to the DLC3.
    2. Turn the ignition switch to ON.
    3. Turn the Techstream on.
    4. Enter the following menus: Powertrain / Engine and ECT / Data List / 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.INSPECT STOP LIGHT SWITCH (TERMINAL VOLTAGE)
Corolla. Zre142 Aze141.2Az-Fe Engine Control.Sfi 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
    A1-2 - Body ground
    		Always
    		11 to 14 V
    A1-3 - Body ground
    		Ignition switch ON
    		11 to 14 V

  1. Reconnect the stop light switch connector.



NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK


2.INSPECT STOP LIGHT SWITCH

  1. Inspect the stop light switch (COROLLA_ZRE142 RM0000014D9026X.html).



NG
REPLACE STOP LIGHT SWITCH (COROLLA_ZRE142 RM0000033ZK00DX.html)
OK


3.INSPECT ECM (STP AND ST1- VOLTAGE)
Corolla. Zre142 Aze141.2Az-Fe Engine Control.Sfi 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
    A50-35 (ST1-) - Body ground
    		Brake pedal released
    		7.5 to 14 V
    Brake pedal depressed
    		Below 1.5 V
    A50-36 (STP) - Body ground
    		Brake pedal released
    		Below 1.5 V
    Brake pedal depressed
    		7.5 to 14 V

  1. Reconnect the ECM connector.



NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

REPLACE ECM (COROLLA_ZRE142 RM000002WT402ZX.html)