C1426

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

DESCRIPTION

The skid control ECU (housed in the actuator assembly) inputs stop light switch signals and the condition of brake operation.

The skid control ECU has an open detection circuit, which outputs 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).





WIRING DIAGRAM

Refer to DTC C1425 C1425.

INSPECTION PROCEDURE

NOTICE:
When replacing the brake actuator assembly, perform zero point calibration Check for Intermittent Problems.

PROCEDURE

1. 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 -- INSPECT STOP FUSE
OK -- Continue to next step.

2. READ VALUE ON TECHSTREAM (STOP LIGHT SWITCH)

(a) Connect Techstream to the DLC3.

(b) Turn the ignition switch on (IG).

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

ABS / VSC / TRAC:





(d) Check that the stop light switch display and brake pedal load sensing switch display observed on Techstream change according to brake pedal operation.

OK:

The Techstream displays ON or OFF according to brake pedal operation.

(e) Slowly depress the brake pedal, and check when the stop light switch and brake pedal load sensing switch turn ON.

OK:

First the stop light switch should turn ON, and then the brake pedal load sensing switch should turn ON.

Result:





C -- CHECK BRAKE PEDAL AND STOP LIGHT SWITCH INSTALLATION

B -- CHECK HARNESS AND CONNECTOR (SKID CONTROL ECU - ENGINE ROOM RELAY BLOCK)
A -- Continue to next step.

3. RECONFIRM DTC

(a) Turn the ignition switch off.

(b) Clear the DTCs .

(c) Start the engine.

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

(e) Check if the same DTC is recorded .

Result:





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

B -- REPLACE BRAKE ACTUATOR ASSEMBLY Removal

A -- CHECK FOR INTERMITTENT PROBLEMS (SYMPTOM SIMULATION) Diagnosis System

4. INSPECT STOP FUSE

(a) Remove the STOP fuse from the main body ECU (instrument panel junction block).





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

Standard resistance:





NG -- REPLACE STOP FUSE
OK -- Continue to next step.

5. INSPECT STOP LIGHT SWITCH (POWER SOURCE TERMINAL)

(a) Install the STOP fuse.





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

(c) Disconnect the stop light switch connector.

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

Standard voltage:





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

6. INSPECT STOP LIGHT SWITCH

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





Standard resistance:





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

7. INSPECT STOP LIGHT CONTROL RELAY

(a) Remove the stop light control relay.





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

Standard resistance:





NG -- REPLACE STOP LIGHT CONTROL RELAY
OK -- Continue to next step.

8. CHECK HARNESS AND CONNECTOR (STOP LIGHT SWITCH - ENGINE ROOM RELAY BLOCK)

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





Standard resistance:





NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.

9. CHECK HARNESS AND CONNECTOR (SKID CONTROL ECU - ENGINE ROOM RELAY BLOCK)

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





(b) Disconnect the skid control ECU connector.

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

Standard resistance:





NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.

10. RECONFIRM DTC

(a) Clear the DTCs .

(b) Start the engine.

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

(d) Check if the same DTC is recorded .

HINT
Reinstall the relay, connectors, etc. and restore the vehicle to its prior condition before rechecking for DTCs.

Result:





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

B -- REPLACE BRAKE ACTUATOR ASSEMBLY Removal

A -- INSPECT LIGHTING SYSTEM (STOP LIGHT CIRCUIT) Symptom Related Diagnostic Procedures

11. CHECK HARNESS AND CONNECTOR (SKID CONTROL ECU - ENGINE ROOM RELAY BLOCK)

(a) Turn the ignition switch off.





(b) Remove the stop light control relay.

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

(d) Disconnect the skid control ECU connector.

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

Standard resistance:





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

NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR

OK -- REPLACE BRAKE ACTUATOR ASSEMBLY Removal

12. CHECK BRAKE PEDAL AND STOP LIGHT SWITCH INSTALLATION

(a) Turn the ignition switch off.

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

OK:

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

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

NG -- ADJUST BRAKE PEDAL OR STOP LIGHT SWITCH Adjustments

OK -- REPLACE BRAKE PEDAL SUB-ASSEMBLY (BRAKE PEDAL LOAD SENSING SWITCH) Disassembly