DESCRIPTION
The stop light switch is a duplex system that transmits 2 signals: STP and ST1-. These 2 signals are used by the ECM to monitor whether or not the brake system is working properly. If 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 |
DTC No. |
DTC Detection Condition |
Trouble Area |
---|---|---|
P0504 |
All of the following conditions continue for 0.5 seconds or more (1 trip detection logic): (a) The ignition switch is ON. (b) The STP signal is OFF when the ST1- signal is OFF. |
|
WIRING DIAGRAM
CAUTION / NOTICE / HINT
NOTICE:
Inspect the fuses for circuits related to this system before performing the following inspection procedure.
HINT:
Brake Pedal Operation |
Stop Light Switch |
ST1 |
---|---|---|
Depressed |
ON |
ON |
Released |
OFF |
OFF |
PROCEDURE
1. |
INSPECT STOP LIGHT SWITCH ASSEMBLY (TERMINAL VOLTAGE) |
(a) Disconnect the stop light switch assembly connector. |
|
(b) Measure the voltage according to the value(s) in the table below.
Standard Voltage:
Tester Connection |
Switch Condition |
Specified Condition |
---|---|---|
A35-2 - Body ground |
Always |
11 to 14 V |
A35-4 - Body ground |
Ignition switch ON |
11 to 14 V |
*a |
Front view of wire harness connector (to Stop Light Switch Assembly) |
NG | ![]() |
REPAIR OR REPLACE HARNESS OR CONNECTOR |
|
2. |
INSPECT STOP LIGHT SWITCH ASSEMBLY |
(a) Inspect the stop light switch assembly (See page
).
NG | ![]() |
REPLACE STOP LIGHT SWITCH ASSEMBLY |
|
3. |
INSPECT ECM (STP AND ST1- VOLTAGE) |
(a) Disconnect the ECM connector.
(b) Turn the ignition switch to ON.
(c) Measure the voltage according to the value(s) in the table below.
Standard Voltage:
Tester Connection |
Condition |
Specified Condition |
---|---|---|
A49-39 (ST1-) - Body ground |
Brake pedal released |
7.5 to 14 V |
Brake pedal depressed |
Below 1.5 V |
|
A49-29 (STP) - Body ground |
Brake pedal released |
Below 1.5 V |
Brake pedal depressed |
7.5 to 14 V |
*a |
Brake pedal depressed |
*b |
Brake pedal released |
*c |
Front view of wire harness connector (to ECM) |
- |
- |
OK | ![]() |
REPLACE ECM |
NG | ![]() |
REPAIR OR REPLACE HARNESS OR CONNECTOR |
Calibration
CALIBRATION
1. ROTATION ANGLE SENSOR INITIALIZATION AND TORQUE SENSOR ZERO POINT CALIBRATION
NOTICE:
Clear the rotation angle sensor calibration value, initialize the rotation angle
sensor, and calibrate the torque sensor zero point if any of the followin ...
Cursor or Map Rotates when Vehicle Stopped
PROCEDURE
1.
CHECK CONDITION
(a) Check with the customer if the vehicle has been turned by a turntable.
OK:
Vehicle has not been turned by a turntable.
HINT:
If the vehicle is turned on a turntable with ...
System Description
SYSTEM DESCRIPTION
1. LIN COMMUNICATION SYSTEM DESCRIPTION
The LIN communication system is used for communication between the components
in the table below. If communication cannot be performed through LIN communication
because of an open in the communic ...