Open in Stop Light Switch Circuit - ABS (Antilock Brake System)

BRAKE CONTROL: ANTI-LOCK BRAKE SYSTEM: C1249/49: Open in Stop Light Switch Circuit

DTC C1249/49 - Open in Stop Light Switch Circuit

DESCRIPTION

This circuit recognizes brake operation by sending a stop light signal to the skid control ECU.
The skid control ECU has an open detection circuit, which outputs this DTC when detecting an open in the stop light signal input line (STP terminal) or the ground line of the stop light circuit with the stop light switch off (brake pedal not depressed).






WIRING DIAGRAM





INSPECTION PROCEDURE
HINT: Check the condition of each related circuit connector before troubleshooting Electronic Circuit Inspection Procedure.

PROCEDURE

1. CHECK STOP LIGHT SWITCH OPERATION (STOP LIGHT SWITCH CIRCUIT)
(a) Check that the stop lights come on when the brake pedal is depressed and goes off when the brake pedal is released.
OK:






NG -- INSPECT STOP LIGHT SWITCH ASSEMBLY (POWER SOURCE TERMINAL VOLTAGE)
OK -- Continue to next step.
2. INSPECT SKID CONTROL ECU CONNECTOR (STP TERMINAL)




(a) Disconnect the skid control ECU connector.
(b) Measure the voltage according to the value(s) in the table below.
Standard voltage:






NG -- CHECK HARNESS AND CONNECTOR (STOP LIGHT SWITCH TO SKID CONTROL ECU)
OK -- Continue to next step.
3. INSPECT SKID CONTROL ECU CONNECTOR (GND TERMINAL CONTINUITY)




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





(b) Connect the connector.
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR (GND CIRCUIT)
OK -- Continue to next step.
4. RECONFIRM DTC
(a) Clear the DTC ABS (Antilock Brake System).
(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 ABS (Antilock Brake System).
HINT: Reinstall the sensors, connectors, etc. and restore the vehicle to its prior condition before rechecking for DTCs.

Result:






C -- PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE
B -- REPLACE BRAKE ACTUATOR ASSEMBLY
A -- CHECK FOR INTERMITTENT PROBLEMS (SYMPTOM SIMULATION)
5. INSPECT STOP LIGHT SWITCH ASSEMBLY (POWER SOURCE TERMINAL VOLTAGE)




(a) Disconnect the stop light switch connector.
(b) 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 ASSEMBLY




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






NG -- REPLACE STOP LIGHT SWITCH ASSEMBLY
OK -- Continue to next step.
7. CHECK HARNESS AND CONNECTOR (STOP LIGHT SWITCH TO SKID CONTROL ECU)




(a) Disconnect the stop light switch connector and skid control ECU connector.
(b) Measure the resistance according to the value(s) in the table below.
Standard resistance:





(c) Connect the connector.
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR (STOP LIGHT SWITCH TO SKID CONTROL ECU)
OK -- REPAIR OR REPLACE HARNESS OR CONNECTOR (STOP LIGHT CIRCUIT)