DESCRIPTION
The skid control ECU (brake actuator assembly) inputs stop light switch signals and brake operation condition.
The skid control ECU (brake actuator assembly) has an open detection circuit, which stores this DTC when detecting an open in the stop light input line or the ground line of the stop light circuit with the stop light switch off (brake pedal not depressed).
DTC Code | DTC Detection Condition | Trouble Area |
---|---|---|
C1426 | When the brake pedal load sensing switch is on, the master cylinder pressure is 2 MPa or higher and the deceleration calculated from the vehicle speed is 0.2 G or more, the stop light switch is off for 2 seconds or more. |
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WIRING DIAGRAM
Refer to DTC C1425 Click here.
INSPECTION PROCEDURE
Note
When replacing the skid control ECU (brake actuator assembly), perform calibration Click here.
Inspect the fuses for circuits related to this system before performing the following inspection procedure.
PROCEDURE
CHECK STOP LIGHT OPERATION
Check that the stop lights come on when the brake pedal is depressed, and go off when the brake pedal is released.
OK | ||||||
---|---|---|---|---|---|---|
|
NG |
OK |
READ VALUE USING INTELLIGENT TESTER (STOP LIGHT SW/BRAKE PEDAL LOAD SENSING SW)
Turn the ignition switch off
Connect the intelligent tester to the DLC3.
Turn the ignition switch to ON.
Turn the intelligent tester on.
Enter the following menus: Chassis / ABS/VSC/TRC / Data List.
Tester Display | Measurement Item/Range | Normal Condition | Diagnostic Note |
---|---|---|---|
Stop Light SW | Stop light switch/ ON or OFF | ON: Brake pedal depressed OFF: Brake pedal released |
- |
Brake Pedal Load Sensing SW | Brake pedal load sensing switch/ ON or OFF | ON: Brake pedal depressed beyond specified point OFF: Brake pedal not depressed beyond specified point |
- |
Check that the stop light switch display and brake pedal load sensing switch display observed on the intelligent tester change according to the brake pedal operation.
OK |
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The intelligent tester displays ON or OFF according to brake pedal operation. |
Slowly depress the brake pedal and check when the stop light switch and brake pedal load sensing switch are turned on.
OK |
---|
The stop light switch turns on first, and then the brake pedal load sensing switch turns on. |
Result | Proceed to |
---|---|
OK | A |
NG (Turning on of stop light switch is not confirmed) | B |
NG (Brake pedal load sensing switch turns on first) | C |
B |
C |
ADJUST BRAKE PEDAL AND STOP LIGHT SWITCH ASSEMBLY INSTALLATION Click here |
A |
RECONFIRM DTC
Turn the ignition switch off.
Clear the DTCs Click here.
Start the engine.
Depress the brake pedal several times to test the stop light circuit.
Check if the same DTC is output Click here.
Result | Proceed to |
---|---|
DTC C1426 is not output | A |
DTC C1426 is output | B |
B |
USE SIMULATION METHOD TO CHECK Click here |
A |
REPLACE BRAKE ACTUATOR ASSEMBLY Click here
CHECK TERMINAL VOLTAGE AND RESISTANCE (STOP LIGHT SWITCH ASSEMBLY POWER SOURCE TERMINAL)
Make sure that there is no looseness in the locking part and connecting part of the connectors.
Disconnect the A85 stop light switch assembly connector.
*a | Front view of wire harness connector (to Stop Light Switch Assembly) |
Measure the voltage according to the value(s) in the table below.
Standard Voltage | ||||||
---|---|---|---|---|---|---|
|
Measure the resistance according to the value(s) in the table below.
Standard Resistance | ||||||
---|---|---|---|---|---|---|
|
NG |
REPAIR OR REPLACE HARNESS OR CONNECTOR (POWER SOURCE CIRCUIT) |
OK |
CHECK TERMINAL VOLTAGE (STP)
Make sure that there is no looseness at the locking parts and connecting parts of the connectors.
Disconnect the A6 skid control ECU (brake actuator assembly) connector.
*a | Front view of wire harness connector (to Skid Control ECU [Brake Actuator Assembly]) |
Measure the voltage according to the value(s) in the table below.
Standard Voltage | ||||||||
---|---|---|---|---|---|---|---|---|
|
NG |
OK |
REPLACE BRAKE ACTUATOR ASSEMBLY Click here
CHECK HARNESS AND CONNECTOR (STOP LIGHT SWITCH ASSEMBLY- BRAKE ACTUATOR ASSEMBLY)
Disconnect the A85 stop light switch assembly connector.
Disconnect the A6 skid control ECU (brake actuator assembly) connector.
Measure the resistance according to the value(s) in the table below.
Standard Resistance | |||||||||
---|---|---|---|---|---|---|---|---|---|
|
NG |
REPAIR OR REPLACE HARNESS OR CONNECTOR |
OK |
REPLACE STOP LIGHT SWITCH ASSEMBLY Click here
ADJUST BRAKE PEDAL AND STOP LIGHT SWITCH ASSEMBLY INSTALLATION
Adjust the brake pedal height and stop light switch assembly installation Click here.
NEXT |
RECONFIRM DTC
Clear the DTCs Click here.
Start the engine.
Depress the brake pedal several times to test the stop light circuit.
Check if the same DTC is output Click here.
Result | Proceed to |
---|---|
DTC C1426 is not output | A |
DTC C1426 is output | B |
B |
REPLACE BRAKE WITH SWITCH PEDAL SUB-ASSEMBLY Click here |
A |
END