Dtc C1A4B Stop Light Relay Circuit


DESCRIPTION

WIRING DIAGRAM

INSPECTION PROCEDURE

CHECK FOR DTC (VEHICLE STABILITY CONTROL SYSTEM)

CHECK STOP LIGHT OPERATION

READ VALUE USING INTELLIGENT TESTER (STOP LIGHT SW)

PERFORM ACTIVE TEST USING INTELLIGENT TESTER (STOP LIGHT RELAY)

CHECK TERMINAL VOLTAGE (STP2)

RECONFIRM DTC

CHECK TERMINAL VOLTAGE AND RESISTANCE (+B, GND)

CHECK TERMINAL VOLTAGE (STP)

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

CHECK TERMINAL VOLTAGE (STP)

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

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

REPLACE STOP LIGHT CONTROL ECU

CHECK FOR DTC (PRE-CRASH SAFETY SYSTEM)

DTC C1A4B Stop Light Relay Circuit


DESCRIPTION

The skid control ECU outputs a stop light operation signal to the stop light control ECU. When the skid control ECU detects a malfunction in the stop light circuit, the driving support ECU outputs DTC C1A4B.

DTC Code
DTC Detection Condition
Trouble Area
C1A4B
  1. For the pre-crash safety system:
    1. The engine switch is on (IG).
  1. For the radar cruise control system:
    1. The vehicle is being driven at 50 km/h (31 mph) or more and the ACC main switch is ON.
When the skid control ECU detects a malfunction* in the stop light control ECU circuit, the skid control ECU sends a malfunction warning signal via CAN to the driving support ECU and a DTC is output.
*: Condition for skid control ECU malfunction warning signal output. When the voltage at the IG1 terminal is between 11 and 14 V and the stop light illumination output (STP0) is ON, there is no input signal to the STP2 terminal for 5 seconds or more, or when the input signals to terminals STP and STP2 are different for 5 seconds or more when the voltage at the IG1 terminal is between 11 and 14 V and the stop light illumination output (STP0) is OFF.
  1. Lighting system
  2. Harness or connector
  3. Stop light control ECU
  4. Driving support ECU

WIRING DIAGRAM


Land Cruiser, Land Cruiser Prado. Grj150 Trj150,155 Kdj150,155 Lj150, Gdj150,155.Pre-Crash Safety.Pre-Crash Safety System. Dtc C1A4B Stop Light Relay Circuit


INSPECTION PROCEDURE

NOTICE:
  1. When replacing the master cylinder solenoid, perform calibration (LandCruiser RM00000452J00ZX.html).
  2. Inspect the fuses for circuits related to this system before performing the following inspection procedure.
  3. When replacing the driving support ECU, always replace it with a new one and be sure to perform initialization (LandCruiser RM000002OJL01OX.html). If an ECU which was installed to another vehicle is used, the information stored in the ECU will not match the information from the vehicle, and as a result, a DTC may be stored.
HINT:
  1. When DTC C1425 is output together with DTC C1380, inspect and repair the trouble areas indicated by DTC C1425 first (LandCruiser RM000000XIE0VFX.html).
  2. This circuit uses CAN communication. Therefore, if there are any malfunctions in the communication circuit, one or more DTCs in the CAN communication system are output.
1.CHECK FOR DTC (VEHICLE STABILITY CONTROL SYSTEM)

  1. Check for DTCs (LandCruiser RM0000046KV016X.html).

    OK:
    Vehicle stability control system DTCs are not output.


NG
GO TO VEHICLE STABILITY CONTROL SYSTEM (LandCruiser RM0000045Z601DX.html)
OK


2.CHECK STOP LIGHT OPERATION

  1. Check that the stop lights come on when the brake pedal is depressed and go off when the brake pedal is released.

    OK:
    Condition
    		Illumination Condition
    Brake pedal depressed
    		On
    Brake pedal released
    		Off


NG
Go to step 7
OK


3.READ VALUE USING INTELLIGENT TESTER (STOP LIGHT SW)

  1. Turn the ignition switch off.

  1. Connect the intelligent tester to the DLC3.

  1. Turn the ignition switch to ON.

  1. Turn the intelligent tester on.

  1. Enter the following menus: Chassis / ABS/VSC/TRC / Data List.

    ABS/VSC/TRC
    Tester Display
    		Measurement Item/Range
    		Normal Condition
    		Diagnostic Note
    Stop Light SW
    		Stop light switch / ON or OFF
    		ON: Brake pedal depressed
    OFF: Brake pedal released
    		-

  1. Check that the stop light switch condition observed on the intelligent tester changes according to brake pedal operation.

    OK:
    The intelligent tester displays ON or OFF according to brake pedal operation.


NG
Go to step 10
OK


4.PERFORM ACTIVE TEST USING INTELLIGENT TESTER (STOP LIGHT RELAY)

  1. Turn the ignition switch off.

  1. Connect the intelligent tester to the DLC3.

  1. Turn the ignition switch to ON.

  1. Turn the intelligent tester on.

  1. Enter the following menus: Chassis / ABS/VSC/TRC / Active Test.

    ABS/VSC/TRC
    Tester Display
    		Test Part
    		Control Range
    		Diagnostic Note
    Stop Light Relay
    		Stop light control ECU
    		ECU ON/OFF
    		Observe the stop lights (do not come on for 2 to 5 seconds).

  1. While performing the Active Test, check the illumination condition of the stop lights and "Stop Light Relay Output" in the Data List.

    ABS/VSC/TRC
    Tester Display
    		Measurement Item/Range
    		Normal Condition
    		Diagnostic Note
    Stop Light Relay Output
    		Stop light control ECU output/ ON or OFF
    		ON: Stop light control ECU on (Stop lights on)
    OFF: Stop light control ECU off (Stop lights off)
    		-

Result
Result
Proceed to
When Active Test performed, Data List item changes between ON and OFF and stop lights turn on and off
A
When Active Test performed, Data List item changes between ON and OFF, but stop lights do not turn on
B


B
Go to step 11
A


5.CHECK TERMINAL VOLTAGE (STP2)

  1. Disconnect the A7 skid control ECU connector.



    Land Cruiser, Land Cruiser Prado. Grj150 Trj150,155 Kdj150,155 Lj150, Gdj150,155.Pre-Crash Safety.Pre-Crash Safety System. Dtc C1A4B Stop Light Relay Circuit

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

    Standard Voltage:
    Tester Connection
    		Condition
    		Specified Condition
    A7-45 (STP2) - Body ground
    		Brake pedal depressed
    		8 to 14 V
    Brake pedal released
    		Below 1.5 V
    Text in Illustration
    *a
    		Front view of wire harness connector
    (to Skid Control ECU)


NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK


6.RECONFIRM DTC

  1. Clear the DTCs (LandCruiser RM0000046KV016X.html).

  1. Start the engine.

  1. Perform a road test.

  1. Check if the same DTC is output (LandCruiser RM0000046KV016X.html).

    Result
    Result
    		Proceed to
    DTC is not output
    		A
    DTC is output (for LHD)
    		B
    DTC is output (for RHD)
    		C


B
REPLACE MASTER CYLINDER SOLENOID (LandCruiser RM00000171U02DX.html)

C
REPLACE MASTER CYLINDER SOLENOID (LandCruiser RM00000171U02EX.html)
A

USE SIMULATION METHOD TO CHECK (LandCruiser RM000003YMJ00XX.html)

7.CHECK TERMINAL VOLTAGE AND RESISTANCE (+B, GND)

  1. Disconnect the A54 stop light control ECU connector.



    Land Cruiser, Land Cruiser Prado. Grj150 Trj150,155 Kdj150,155 Lj150, Gdj150,155.Pre-Crash Safety.Pre-Crash Safety System. Dtc C1A4B Stop Light Relay Circuit

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

    Standard Voltage:
    Tester Connection
    		Condition
    		Specified Condition
    A54-6 (+B) - Body ground
    		Always
    		11 to 14 V

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

    Standard Resistance:
    Tester Connection
    		Condition
    		Specified Condition
    A54-8 (GND) - Body ground
    		Always
    		Below 1 Ω
    Text in Illustration
    *a
    		Front view of wire harness connector
    (to Stop Light Control ECU)


NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK


8.CHECK TERMINAL VOLTAGE (STP)

  1. Disconnect the A54 stop light control ECU connector.



    Land Cruiser, Land Cruiser Prado. Grj150 Trj150,155 Kdj150,155 Lj150, Gdj150,155.Pre-Crash Safety.Pre-Crash Safety System. Dtc C1A4B Stop Light Relay Circuit

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

    Standard Voltage:
    Tester Connection
    		Condition
    		Specified Condition
    A54-5 (STP) - Body ground
    		Brake pedal depressed
    		8 to 14 V
    Brake pedal released
    		Below 1.5 V
    Text in Illustration
    *a
    		Front view of wire harness connector
    (to Stop Light Control ECU)


NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK


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

  1. Disconnect the A54 stop light control ECU connector.

  1. Disconnect the A7 skid control ECU connector.

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

    Standard Resistance:
    Tester Connection
    		Condition
    		Specified Condition
    A54-1 (OUT) - A7-45 (STP2)
    		Always
    		Below 1 Ω
    A54-1 (OUT) - Body ground
    		Always
    		10 kΩ or higher


NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

REPLACE STOP LIGHT CONTROL ECU (LandCruiser RM000003MWQ02KX.html)

10.CHECK TERMINAL VOLTAGE (STP)

  1. Disconnect the A7 skid control ECU connector.



    Land Cruiser, Land Cruiser Prado. Grj150 Trj150,155 Kdj150,155 Lj150, Gdj150,155.Pre-Crash Safety.Pre-Crash Safety System. Dtc C1A4B Stop Light Relay Circuit

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

    Standard Voltage:
    Tester Connection
    		Condition
    		Specified Condition
    A7-7 (STP) - Body ground
    		Brake pedal depressed
    		8 to 14 V
    Brake pedal released
    		Below 1.5 V
    Text in Illustration
    *a
    		Front view of wire harness connector
    (to Skid Control ECU)
    Result
    Result
    		Proceed to
    NG
    		A
    OK (for LHD)
    		B
    OK (for RHD)
    		C


B
REPLACE MASTER CYLINDER SOLENOID (LandCruiser RM00000171U02DX.html)

C
REPLACE MASTER CYLINDER SOLENOID (LandCruiser RM00000171U02EX.html)
A

REPAIR OR REPLACE HARNESS OR CONNECTOR

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

  1. Disconnect the A7 skid control ECU connector.

  1. Disconnect the A54 stop light control ECU connector.

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

    Standard Resistance:
    Tester Connection
    		Condition
    		Specified Condition
    A7-16 (STP0) - A54-9 (ACC)
    		Always
    		Below 1 Ω
    A7-16 (STP0) - Body ground
    		Always
    		10 kΩ or higher


NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK


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

  1. Disconnect the A7 skid control ECU connector.

  1. Disconnect the A54 stop light control ECU connector.

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

    Standard Resistance:
    Tester Connection
    		Condition
    		Specified Condition
    A7-45 (STP2) - A54-1 (OUT)
    		Always
    		Below 1 Ω
    A7-45 (STP2) - Body ground
    		Always
    		10 kΩ or higher


NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK


13.REPLACE STOP LIGHT CONTROL ECU

  1. Temporally replace the stop light control ECU with a new or normally function one (LandCruiser RM000003MWQ02KX.html).


NEXT


14.CHECK FOR DTC (PRE-CRASH SAFETY SYSTEM)

  1. Clear the DTCs (LandCruiser RM0000043K500GX.html).

    HINT:
    If the detection conditions are not met, the system cannot detect malfunctions.
    1. Pre-crash safety system:
      1. Turn the ignition switch off.
      2. Connect the intelligent tester to the DLC3.
      3. Turn the ignition switch to ON.
      4. Turn the intelligent tester on.
      5. Enter the following menus: Chassis / ABS/VSC/TRC / Active Test.

        ABS/VSC/TRC
        Tester Display
        		Test Part
        		Control Range
        		Diagnostic Note
        Stop Light Relay
        		STOP light control ECU
        		ECU ON/OFF
        		Observe the stop lights (do not come on for 2 to 5 seconds).
      6. While performing the Active Test, check the illumination condition of the stop lights and "Stop Light Relay Output" in the Data List.

        ABS/VSC/TRC
        Tester Display
        		Measurement Item/Range
        		Normal Condition
        		Diagnostic Note
        Stop Light Relay Output
        		STOP light control ECU output/ ON or OFF
        		ON: Stop light control ECU output on (Stop lights on)
        OFF: Stop light control ECU output off (Stop lights off)
        		-

  1. Make sure the following conditions are met:

    1. Radar cruise control system:
      1. The vehicle is being driven at a speed of approximately 50 km/h (31 mph) or more and the distance control switch is on.

  1. Check for DTCs (LandCruiser RM0000046KV016X.html).

    OK:
    DTCs C1A4B are not output.


NG
REPLACE DRIVING SUPPORT ECU (LandCruiser RM000002OJO01NX.html)
OK

END