Stop Light Control Relay Malfunction - Vehicle Stability Control System

BRAKE CONTROL / DYNAMIC CONTROL SYSTEMS: VEHICLE STABILITY CONTROL SYSTEM: C1380/64: Stop Light Control Relay Malfunction
C1380/64 - Stop Light Control Relay Malfunction

DESCRIPTION

Upon receiving the CRAWL or hill-start assist control operating signal from the skid control ECU, the relay contact turns on and the stop light comes on.





WIRING DIAGRAM





INSPECTION PROCEDURE

NOTICE:
When replacing the master cylinder solenoid, perform zero point calibration Programming and Relearning.

PROCEDURE

1. CHECK STOP LIGHT SWITCH OPERATION

(a) Check that the stop light comes on when the brake pedal is depressed, and goes off when the brake pedal is released.

OK:

Stop light switch function is normal.

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

NG -- GO TO LIGHTING SYSTEM (STOP LIGHT CIRCUIT) Stop Light Circuit
OK -- Continue to next step.

2. INSPECT SKID CONTROL ECU (STP TERMINAL)

(a) Disconnect the A24 skid control ECU 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.

3. INSPECT SKID CONTROL ECU (STP2 TERMINAL)

(a) 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. PERFORM ACTIVE TEST USING TECHSTREAM (STOP LIGHT RELAY)

(a) Reconnect the A24 skid control ECU connector.

(b) Connect the Techstream to the DLC3.

(c) Turn the engine switch on (IG) and turn the Techstream on.

(d) Enter the following menus: Chassis / ABS/VSC/TRAC / Active Test.

ABS/VSC/TRAC





(e) Check that "ON" and "OFF" of the stop light can be shown on the rear combination light by the Techstream.

OK:

The stop light turns on or off in accordance with the Techstream.

NG -- INSPECT BRK LP RELAY (POWER SOURCE TERMINAL)
OK -- Continue to next step.

5. RECONFIRM DTC

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

(b) Check if the same DTC is output Reading and Clearing Diagnostic Trouble Codes.

HINT
Reinstall the sensors, connectors, etc. and restore the previous vehicle conditions before rechecking for DTCs.

Result





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

A -- REPLACE MASTER CYLINDER SOLENOID Disassembly

6. INSPECT BRK LP RELAY (POWER SOURCE TERMINAL)

(a) Remove the BRK LP relay.





(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.

7. INSPECT BRK LP RELAY

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





Standard Resistance:





NG -- REPLACE BRK LP RELAY
OK -- Continue to next step.

8. INSPECT SKID CONTROL ECU (STPO TERMINAL)

(a) Install the BRK LP relay.





(b) Disconnect the A24 skid control ECU connector.

(c) 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.

9. RECONFIRM DTC

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

(b) Check if the same DTC is output Reading and Clearing Diagnostic Trouble Codes.

HINT
Reinstall the sensors, connectors, etc. and restore the previous vehicle conditions before rechecking for DTCs.

Result





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

A -- REPLACE MASTER CYLINDER SOLENOID Disassembly