Open in Stop Light Switch Circuit - Vehicle Stability Control System (for BOSCH Made)

BRAKE CONTROL: VEHICLE STABILITY CONTROL SYSTEM (for BOSCH Made): C1249/49: Open in Stop Light Switch Circuit
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 go off when the brake pedal is released.

OK:





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

2. INSPECT SKID CONTROL ECU (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 (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 Vehicle Stability Control System (for BOSCH Made).

(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 Vehicle Stability Control System (for BOSCH Made).

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

Result:





HINT
It is suspected that the DTCs were output due to a bad connection of the connector terminal.

B -- REPLACE BRAKE ACTUATOR ASSEMBLY Removal

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

5. CHECK HARNESS AND CONNECTOR (STOP LIGHT SWITCH 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 (STOP LIGHT SWITCH 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:





(b) Connect the connector.

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 connectors.

NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR (STOP LIGHT SWITCH TO SKID CONTROL ECU)

OK -- REPAIR OR REPLACE HARNESS OR CONNECTOR (STOP LIGHT CIRCUIT)