Open in Stop Light Switch Circuit - Electronically Controlled Brake System

BRAKE CONTROL: ELECTRONICALLY CONTROLLED BRAKE SYSTEM: C1249/49: Open in Stop Light Switch Circuit

DTC C1249/49 - Open in Stop Light Switch Circuit

DESCRIPTION

The skid control ECU inputs the stop light switch signal and detects the brake pedal operation status.
The skid control ECU has an open detection circuit, which outputs this DTC if it detects an open in the stop light input line or ground line of the stop light circuit with the stop light switch off (brake pedal not depressed).






WIRING DIAGRAM









INSPECTION PROCEDURE
NOTE: When replacing the skid control ECU, perform initialization and calibration of the linear solenoid valve. Initialization

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 USING TECHSTREAM (STOP LIGHT SWITCH)
(a) Connect the Techstream to the DLC3.
(b) Turn the power switch on (IG).
(c) Select the Data List mode on 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 (SKID CONTROL ECU - STOP LIGHT SWITCH)
OK -- Continue to next step.
3. INSPECT SKID CONTROL ECU (IG1 TERMINAL)
(a) Turn the power 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) Turn the power switch on (IG).
(e) Measure the voltage according to the value(s) in the table below.
Standard voltage:






NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR (IG1 CIRCUIT)
OK -- Continue to next step.
4. INSPECT SKID CONTROL ECU (GND TERMINAL)
(a) Turn the power switch off.





(b) Make sure that there is no looseness at the locking part and the connecting part of the connectors.
(c) Disconnect the skid control ECU connectors.
(d) Measure the resistance according to the value(s) in the table below.
Standard resistance:






NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR (GND CIRCUIT)
OK -- Continue to next step.
5. RECONFIRM DTC
(a) Reconnect the skid control ECU connectors.
(b) Clear the DTCs.
(c) Turn the power switch on (READY).
(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 SKID CONTROL ECU
A -- CHECK FOR INTERMITTENT PROBLEMS (SYMPTOM SIMULATION)
6. 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.
7. 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 connector.
(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.
8. INSPECT STOP LIGHT SWITCH





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






NG -- REPLACE STOP LIGHT SWITCH
OK -- Continue to next step.
9. 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.
10. 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.
11. 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 connector.





(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.
12. RECONFIRM DTC
(a) Clear the DTCs.
(b) Turn the power switch on (READY).
(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 SKID CONTROL ECU
A -- INSPECT LIGHTING SYSTEM (STOP LIGHT CIRCUIT)
13. CHECK HARNESS AND CONNECTOR (SKID CONTROL ECU - STOP LIGHT SWITCH)
(a) Turn the power switch off.





(b) Make sure that there is no looseness at the locking part and the connecting part of the connectors.
(c) Disconnect the skid control ECU connector and the stop light switch connector.
(d) 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 SKID CONTROL ECU