Brand:
Toyota
Model Name:
4Runner GRN210 215 UZN210 215
Manual:
Repair Manual
Section:
1Gr-Fe Engine Control System
Title:
Sfi System
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 or released, are detected simultaneously, the ECM interprets this as a malfunction in the stop light switch and sets the DTC.- HINT:
- 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 Conditions | Trouble Areas |
| P0504 | Conditions (a), (b) and (c) continue for 0.5 seconds or more (1 trip detection logic): (a) Ignition switch on (b) Brake pedal released (c) STP signal OFF when ST1- signal OFF |
|
WIRING DIAGRAM
INSPECTION PROCEDURE
- HINT:
- Read freeze frame data using the intelligent tester. 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.
1.CHECK OPERATION OF STOP LIGHT
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.
| REPAIR OR REPLACE STOP LIGHT SWITCH CIRCUIT | |||
| OK | |
 |
2.INSPECT STOP LIGHT SWITCH ASSEMBLY
Remove the stop light switch assembly.
Measure the resistance.
- Standard resistance:
Switch Positions Tester Connections Specified Conditions Switch pin free 1 - 2 Below 1 Ω Switch pin free 3 - 4 10 kΩ or higher Switch pin pushed in 1 - 2 10 kΩ or higher Switch pin pushed in 3 - 4 Below 1 Ω
Reinstall the stop light switch assembly.
| REPLACE STOP LIGHT SWITCH ASSEMBLY | |||
| OK | |
|
3.READ VALUE OF INTELLIGENT TESTER (STP SIGNAL AND ST1 - VOLTAGE)
Connect the intelligent tester to the DLC3.
Turn the ignition switch on and turn the tester on.
Select the following menu items: DIAGNOSIS / ENHANCED OBD II / DATA LIST / PRIMARY / STOP LIGHT SW.
Check the STP signal when the brake pedal is depressed and released.
- Standard:
Brake Pedal Operations Specified Conditions Depressed STP signal ON Released STP signal OFF
Measure the voltage between the terminals of the E6 and E8 ECM connectors.
- Standard voltage:
Tester Connections Brake Pedal Operations Specified Conditions ST1- (E8-16) - E1 (E6-1) Depressed Below 1.5 V ST1- (E8-16) - E1 (E6-1) Released 7.5 to 14 V
| CHECK FOR INTERMITTENT PROBLEMS | |||
| NG | |
|
4.CHECK HARNESS AND CONNECTOR (STOP LIGHT SWITCH - ECM)
Disconnect the S12 stop light switch connector.
Disconnect the E8 ECM connector.
Measure the resistance.
- Standard resistance (Check for open):
Tester Connections Specified Conditions Stop light switch (S12-1) - STP (E8-15) Below 1 Ω Stop light switch (S12-4) - ST1- (E8-16) Below 1 Ω
- Standard resistance (Check for short):
Tester Connections Specified Conditions Stop light switch (S12-1) or STP (E8-15) - Body ground 10 kΩ or higher Stop light switch (S12-4) or ST1- (E8-16) - Body ground 10 kΩ or higher
Reconnect the stop light switch connector.
Reconnect the ECM connector.
| REPAIR OR REPLACE HARNESS OR CONNECTOR | |||
| OK | |
 | |
| REPLACE ECM | |