C1249

BRAKE CONTROL: ELECTRONICALLY CONTROLLED BRAKE SYSTEM: 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. 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 (skid control ECU side).





WIRING DIAGRAM





INSPECTION PROCEDURE

NOTICE:
When replacing the skid control ECU, perform the following operations:

- Initialization of linear solenoid valve and calibration Initialization
- Yaw rate and acceleration sensor zero point calibration Calibration

PROCEDURE

1. INSPECT FUSE (STOP)

(a) Remove the STOP fuse from the main body ECU (driver side junction block).

(b) Measure the resistance of the fuse.

Standard resistance:





NG -- REPLACE 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.

ABS/VSC/TRAC:





(d) Check that the stop light observed on the Techstream changes when the brake pedal is depressed.

OK:

When the brake pedal is depressed, the Techstream displays "ON".

Result





B -- GO TO LIGHTING SYSTEM (HOW TO PROCEED WITH TROUBLESHOOTING) How To Proceed With Troubleshooting
A -- Continue to next step.

3. CHECK TERMINAL VOLTAGE (STOP LIGHT SWITCH)

(a) Disconnect the A35 switch connector.





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

Standard voltage:





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

4. INSPECT STOP LIGHT SWITCH

(a) Disconnect the stop light switch connector.





(b) 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.

5. CHECK HARNESS AND CONNECTOR (SKID CONTROL ECU - STOP LIGHT SWITCH)

(a) Disconnect the A21 ECU connector.

(b) Disconnect the A35 switch 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.

6. CHECK HARNESS AND CONNECTOR (SKID CONTROL ECU - BODY GROUND)

(a) Disconnect the A19 and A21 ECU connectors.

(b) 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.

7. RECONFIRM DTC

(a) Clear the DTC Reading and Clearing Diagnostic Trouble Codes.

(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 Reading and Clearing Diagnostic Trouble Codes.

HINT
Reinstall the sensors, 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 Removal

A -- USE SIMULATION METHOD TO CHECK How To Proceed With Troubleshooting