DTC 49

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 braking condition.
The skid control ECU has a circuit for open detection inside. The skid control ECU outputs the DTC if it detects an open in the stop light signal input line when the stop light switch is off, or an open in the stop light circuit (GND side).






WIRING DIAGRAM









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

PROCEDURE

1. CHECK STOP LIGHT SWITCH OPERATION
(a) Check that the stop light comes on when the brake pedal is depressed and turns off when the brake pedal is released.

OK





HINT: Check the stop light bulb as it may have burnt out.

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

2. CHECK SKID CONTROL ECU (STP VOLTAGE)




(a) Measure the voltage of the connector.
HINT: Measure the voltage from behind the connector with the connector connected to the skid control ECU.

Standard voltage:






NG -- CHECK WIRE HARNESS (SKID CONTROL ECU - STOP LIGHT CONTROL RELAY)
OK -- Continue to next step.

3. RECONFIRM DTC
(a) Clear the DTCs Reading and Clearing Diagnostic Trouble Codes.
(b) Turn the power switch ON (READY).
(c) Check the same DTCs are recorded Reading and Clearing Diagnostic Trouble Codes.

Result





B -- REPLACE SKID CONTROL ECU
A -- PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE
4. INSPECT STOP LIGHT SWITCH ASSEMBLY




(a) Disconnect the stop light switch connector.
(b) Measure the resistance of the switch.
Standard resistance:






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

5. INSPECT STOP LIGHT CONTROL RELAY ASSEMBLY
(a) Check the stop light control relay Testing and Inspection.
OK:
The stop light control relay is normal.
NG -- REPLACE STOP LIGHT CONTROL RELAY ASSEMBLY
OK -- Continue to next step.

6. CHECK WIRE HARNESS (STOP LIGHT SWITCH - STOP LIGHT CONTROL RELAY)




(a) Disconnect the S16 switch connector.
(b) Disconnect the S31 relay connector.
(c) Measure the resistance of the wire harness side connectors.
Standard resistance:






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

7. CHECK WIRE HARNESS (SKID CONTROL ECU - STOP LIGHT CONTROL RELAY)




(a) Disconnect the S8 ECU connector.
(b) Disconnect the S31 relay connector.
(c) Measure the resistance of the wire harness side connectors.
Standard resistance:






NG -- REPAIR OR REPLACE HARNESS AND CONNECTOR
OK -- REPLACE SKID CONTROL ECU