C1426

BRAKE CONTROL / DYNAMIC CONTROL SYSTEMS: VEHICLE STABILITY CONTROL SYSTEM: C1426: Stop Light Switch OFF Stuck Malfunction
C1426 - Stop Light Switch OFF Stuck Malfunction

DESCRIPTION

The skid control ECU receives stop light switch signals and uses them to determine whether or not the brakes are applied.

The skid control ECU has a detection circuit that it uses to detect a short in the stop light input line, or the ground line of the stop light circuit with the stop light switch on (brake pedal depressed).

If the skid control ECU detects a short in this circuit, it will store this DTC.





WIRING DIAGRAM

Refer to DTC C1249 C1249.

INSPECTION PROCEDURE

PROCEDURE

1. CHECK BRAKE PEDAL AND STOP LIGHT SWITCH ASSEMBLY INSTALLATION

(a) Check the brake pedal height and stop light switch assembly installation Adjustments.

OK:

The brake pedal height and stop light switch assembly installation are normal.

HINT
If the on/off status of the stop light switch assembly and the pressure increase information from the master cylinder pressure sensor do not match due to an improperly installed brake pedal or stop light switch assembly, this DTC may be stored. Therefore, be sure to check the installation condition of the pedal and switch before inspecting the input signals and other related parts.

NG -- ADJUST BRAKE PEDAL OR STOP LIGHT SWITCH ASSEMBLY Adjustments
OK -- Continue to next step.

2. CHECK STOP LIGHT OPERATION

(a) Check that the stop lights come on when the brake pedal is depressed, and go off when the brake pedal is released.

OK:





NG -- CHECK HARNESS AND CONNECTOR (POWER SOURCE TERMINAL)
OK -- Continue to next step.

3. READ VALUE USING TECHSTREAM (STOP LIGHT SWITCH ASSEMBLY)

(a) Connect the Techstream to the DLC3.

(b) Turn the ignition switch to ON.

(c) Select the Data List using the Techstream Data List / Active Test.

ABS/VSC/TRAC





(d) Check that the stop light switch display observed on the Techstream changes according to brake pedal operation.

OK:

The Techstream displays on or off according to brake pedal operation.

NG -- CHECK HARNESS AND CONNECTOR (STP TERMINAL)
OK -- Continue to next step.

4. RECONFIRM DTC

(a) Turn the ignition switch off.

(b) Clear the DTCs Reading and Clearing Diagnostic Trouble Codes.

(c) Turn the ignition switch off.

(d) Start the engine.

(e) Depress the brake pedal several times to test the stop light circuit.

(f) Check if the same DTC is output Reading and Clearing Diagnostic Trouble Codes.

Result:





HINT
If troubleshooting has been carried out according to Problem Symptoms Table, refer back to the table and proceed to the next step before replacing parts Problem Symptoms Table.

B -- REPLACE BRAKE ACTUATOR ASSEMBLY Removal

A -- CHECK FOR INTERMITTENT PROBLEMS How To Proceed With Troubleshooting

5. CHECK HARNESS AND CONNECTOR (POWER SOURCE TERMINAL)

(a) Check that the STOP (7.5 A) fuse is normal.





(b) Make sure that there is no looseness at the locking part and the connecting part of the connector.

(c) Disconnect the stop light switch assembly connector.

(d) Measure the voltage according to the value(s) in the table below.

Standard Voltage:





Text in Illustration





NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR (POWER SOURCE CIRCUIT)
OK -- Continue to next step.

6. INSPECT STOP LIGHT SWITCH ASSEMBLY

(a) Measure the resistance according to the value(s) in the table below.





Standard Resistance:





Text in Illustration





NG -- REPLACE STOP LIGHT SWITCH ASSEMBLY Removal
OK -- Continue to next step.

7. CHECK HARNESS AND CONNECTOR (STP TERMINAL)

(a) Reconnect the stop light switch assembly connector.





(b) Make sure that there is no looseness at the locking part and the connecting part of the connector.

(c) Disconnect the skid control ECU connector.

(d) Measure the voltage according to the value(s) in the table below.

Standard Voltage:





HINT
*: The standard voltage value varies depending on the +BS terminal voltage value. The standard voltage is 85% of the +BS terminal voltage.

Text in Illustration





NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR (STP CIRCUIT)
OK -- Continue to next step.

8. RECONFIRM DTC

(a) Reconnect the skid control ECU connector.

(b) Clear the DTCs Reading and Clearing Diagnostic Trouble Codes.

(c) Turn the ignition switch off.

(d) Start the engine.

(e) Depress the brake pedal several times to test the stop light circuit.

(f) Check if the same DTC is output Reading and Clearing Diagnostic Trouble Codes.

Result:





HINT
If troubleshooting has been carried out according to Problem Symptoms Table, refer back to the table and proceed to the next step before replacing parts Problem Symptoms Table.

B -- REPLACE BRAKE ACTUATOR ASSEMBLY Removal

A -- INSPECT LIGHTING SYSTEM (STOP LIGHT CIRCUIT) Problem Symptoms Table

9. CHECK HARNESS AND CONNECTOR (STP TERMINAL)

(a) Turn the ignition switch off.





(b) Make sure that there is no looseness at the locking part and the connecting part of the connector.

(c) Disconnect the skid control ECU connector.

(d) Measure the voltage according to the value(s) in the table below.

Standard Voltage:





HINT
*: The standard voltage value varies depending on the +BS terminal voltage value. The standard voltage is 85% of the +BS terminal voltage.

Text in Illustration





NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR (STP CIRCUIT)
OK -- Continue to next step.

10. CHECK HARNESS AND CONNECTOR (GND1 TERMINAL)

(a) Measure the resistance according to the value(s) in the table below.





Standard Resistance:





Text in Illustration





HINT
If troubleshooting has been carried out according to Problem Symptoms Table, refer back to the table and proceed to the next step before replacing parts Problem Symptoms Table.

NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR (GND1 CIRCUIT)

OK -- REPLACE BRAKE ACTUATOR ASSEMBLY Removal