DTC    C1A05    Stop Light Switch Circuit

DTC    C1A4B    Stop Light Relay Circuit

for Preparation Click here


DESCRIPTION

When the brake pedal is depressed, the stop light switch sends a signal to the driving support ECU assembly. Upon receiving the signal, the driving support ECU assembly cancels the dynamic radar cruise control system. Even if there is a malfunction in the stop light signal circuit while the cruise control is operating, normal driving is maintained due to the fail-safe function. Dynamic radar cruise control is canceled when positive battery voltage is applied to terminal STP-.
When the brake pedal is released, positive voltage is applied to terminal ST1- of the driving support ECU assembly through the IGN fuse and the stop light switch, and the driving support ECU assembly operates the dynamic radar cruise control.
The brake booster with master cylinder (skid control ECU) receives a signal from the driving support ECU assembly and operates the brake actuator. The brake booster with master cylinder (skid control ECU) operates the brake actuator and at the same time illuminates the stop lights by operating the stop light control relay.
The stop light switch assembly sends a brake pedal operation signal to the driving support ECU assembly.
After receiving the signal, the ECM performs fail-safe control by canceling the cruise control function.

DTC No.
DTC Detection Condition
Trouble Area
C1A05
Voltages of terminals ST1- and STP- of driving support ECU assembly are both below 1 V for 1 second
  1. Stop light switch assembly
  2. Stop light switch circuit
  3. Driving support ECU assembly
C1A4B
This trouble code is stored when the brake booster with master cylinder (skid control ECU) detects a malfunction in the stop light control relay circuit for 1 second while the dynamic cruise control is operating.
  1. Stop light control relay circuit
  2. Brake booster with master cylinder (skid control ECU)
  3. Driving support ECU assembly

WIRING DIAGRAM


E222569E03


INSPECTION PROCEDURE

HINT:
Inspect the fuses for circuits related to this system before performing the following inspection procedure.

1.READ VALUE USING INTELLIGENT TESTER (STOP LIGHT SWITCH ASSEMBLY)

  1. Connect the intelligent tester to the DLC3.

  1. Turn the power switch on (IG).

  1. Turn the intelligent tester on.

  1. Enter the following menus: Powertrain / Radar Cruise / Data List.

  1. Check the Data List for proper functioning of the stop light switch.

    Radar Cruise 
    Tester Display
    		Measurement Item/Range
    		Normal Condition
    		Diagnostic Note
    Stop Light SW 1 (M CPU)
    		Stop light switch (Main-CPU) signal / ON or OFF
    		ON: Brake pedal depressed
    OFF: Brake pedal released
    		-
    Stop Light SW 1 (S CPU)
    		Stop light switch (Sub-CPU) signal / ON or OFF
    		ON: Brake pedal depressed
    OFF: Brake pedal released
    		-
    Stop Light SW 2 (M CPU)
    		Stop light switch (Main-CPU) signal / ON or OFF
    		ON: Brake pedal depressed
    OFF: Brake pedal released
    		-

    OK:
    Display changes according to brake pedal operation described in above table.



NG
Go to step 12
OK


2.CHECK HARNESS AND CONNECTOR (STOP LIGHT CONTROL RELAY POWER SOURCE)


    E183992E11

  1. Disconnect the stop light control relay connector.

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

    Standard Voltage:
    Tester Connection
    		Condition
    		Specified Condition
    A27-6 (+B) - Body ground
    		Always
    		11 to 14 V

    Text in Illustration 
    *a
    		Front view of wire harness connector
    (to Stop Light Control Relay)

  1. Reconnect the stop light control relay connector.



NG
REPAIR OR REPLACE HARNESS OR CONNECTOR (STOP LIGHT CONTROL RELAY - STOP FUSE)
OK


3.CHECK HARNESS AND CONNECTOR (STOP LIGHT CONTROL RELAY - BODY GROUND)


    E183992E12

  1. Disconnect the stop light control relay connector.

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

    Standard Resistance (Check for Open):
    Tester Connection
    		Condition
    		Specified Condition
    A27-8 (GND) - Body ground
    		Always
    		Below 1 Ω

    Text in Illustration 
    *a
    		Front view of wire harness connector
    (to Stop Light Control Relay)

  1. Reconnect the stop light control relay connector.



NG
REPAIR OR REPLACE HARNESS OR CONNECTOR (STOP LIGHT CONTROL RELAY - BODY GROUND)
OK


4.CHECK HARNESS AND CONNECTOR (STOP LIGHT CONTROL RELAY - STOP LIGHT SWITCH ASSEMBLY)

  1. Disconnect the stop light control relay connector.

  1. Disconnect the stop light switch assembly connector.

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

    Standard Resistance (Check for Open):
    Tester Connection
    		Condition
    		Specified Condition
    A25-1 - A27-5 (STP)
    		Always
    		Below 1 Ω

    Standard Resistance (Check for Short):
    Tester Connection
    		Condition
    		Specified Condition
    A25-1 or A27-5 (STP) - Body ground
    		Always
    		10 kΩ or higher

  1. Reconnect the stop light switch assembly connector.

  1. Reconnect the stop light control relay connector.



NG
REPAIR OR REPLACE HARNESS OR CONNECTOR (STOP LIGHT CONTROL RELAY - STOP LIGHT SWITCH ASSEMBLY)
OK


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

  1. Disconnect the stop light switch assembly connector.

  1. Disconnect the brake booster with master cylinder (skid control ECU) connector.

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

    Standard Resistance (Check for Open):
    Tester Connection
    		Condition
    		Specified Condition
    A25-1 - A61-33 (STP)
    		Always
    		Below 1 Ω

    Standard Resistance (Check for Short):
    Tester Connection
    		Condition
    		Specified Condition
    A25-1 or A61-33 (STP) - Body ground
    		Always
    		10 kΩ or higher

  1. Reconnect the stop light switch assembly connector.

  1. Reconnect the brake booster with master cylinder (skid control ECU) connector.



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


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

  1. Disconnect the stop light control relay connector.

  1. Disconnect the brake booster with master cylinder (skid control ECU) connector.

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

    Standard Resistance (Check for Open):
    Tester Connection
    		Switch Condition
    		Specified Condition
    A27-1 (OUT) - A61-6 (STP2)
    		Always
    		Below 1 Ω
    A27-5 (STP) - A61-33 (STP)
    		Always
    		Below 1 Ω
    A27-9 (ACC) - A61-3 (STP0)
    		Always
    		Below 1 Ω

    Standard Resistance (Check for Short):
    Tester Connection
    		Switch Condition
    		Specified Condition
    A27-1 (OUT) or A61-6 (STP2) - Body ground
    		Always
    		10 kΩ or higher
    A27-5 (STP) or A61-33 (STP) - Body ground
    		Always
    		10 kΩ or higher
    A27-9 (ACC) or A61-3 (STP0) - Body ground
    		Always
    		10 kΩ or higher

  1. Reconnect the stop light control relay connector.

  1. Reconnect the brake booster with master cylinder (skid control ECU) connector.



NG
REPAIR OR REPLACE HARNESS OR CONNECTOR (STOP LIGHT CONTROL RELAY - SKID CONTROL ECU)
OK


7.INSPECT STOP LIGHT CONTROL RELAY

  1. Inspect the stop light control relay (Click here).



NG
REPLACE STOP LIGHT CONTROL RELAY (Click here)
OK


8.REPLACE BRAKE BOOSTER WITH MASTER CYLINDER (SKID CONTROL ECU)

  1. Replace the brake booster with master cylinder (skid control ECU) (Click herefor LHD, Click here for RHD ).


NEXT


9.CHECK WHETHER DTC OUTPUT RECORDS (DTC C1A05 OR C1A4B)

  1. Connect the intelligent tester to the DLC3.

  1. Turn the power switch on (IG).

  1. Clear the DTCs (Click here).

  1. Perform the following to make sure that the DTC detection conditions are met.

    HINT:
    If the detection conditions are not met, the malfunction cannot be detected.

    1. Drive the vehicle at a speed of 50 km/h (30 mph) and 170 km/h (105 mph).

    2. Turn the cruise control switch (ON-OFF button) on.

    3. Push the -/SET switch to activate the cruise control.

  1. Enter the following menus: Powertrain / Radar Cruise / DTC.

  1. Read the DTCs.

    Result:
    Result
    		Proceed to
    DTC is not output
    		A
    DTC C1A05 or C104B is output
    		B



B
Go to step 10
A

END 

10.REPLACE POWER MANAGEMENT CONTROL ECU

  1. Replace the power management control ECU (Click here).


NEXT


11.CHECK WHETHER DTC OUTPUT RECORDS (DTC C1A05 OR C1A4B)

  1. Connect the intelligent tester to the DLC3.

  1. Turn the power switch on (IG).

  1. Clear the DTCs (Click here).

  1. Perform the following to make sure that the DTC detection conditions are met.

    HINT:
    If the detection conditions are not met, the malfunction cannot be detected.

    1. Drive the vehicle at a speed of 50 km/h (30 mph) and 170 km/h (105 mph).

    2. Turn the cruise control switch (ON-OFF button) on.

    3. Push the -/SET switch to activate the cruise control.

  1. Enter the following menus: Powertrain / Radar Cruise / DTC.

  1. Read the DTCs.

    Result:
    Result
    		Proceed to
    DTC is not output
    		A
    DTC C1A05 or C104B is output
    		B



B
REPLACE DRIVING SUPPORT ECU ASSEMBLY (Click here)
A

END 

12.CHECK HARNESS AND CONNECTOR (STOP LIGHT SWITCH ASSEMBLY - POWER SOURCE)


    A194115E75

  1. Disconnect the stop light switch assembly connector.

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

    Standard Voltage:
    Tester Connection
    		Condition
    		Specified Condition
    A25-2 - Body ground
    		Always
    		11 to 14 V

    Text in Illustration 
    *a
    		Front view of wire harness connector
    (to Stop Light Switch Assembly)

  1. Reconnect the stop light switch assembly connector.



NG
Go to step 17
OK


13.CHECK HARNESS AND CONNECTOR (STOP LIGHT SWITCH ASSEMBLY - POWER SOURCE)


    A194115E75

  1. Disconnect the stop light switch assembly connector.

  1. Turn the power switch on (IG).

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

    Standard Voltage:
    Tester Connection
    		Condition
    		Specified Condition
    A25-4 - Body ground
    		Power switch on (IG)
    		11 to 14 V

    Text in Illustration 
    *a
    		Front view of wire harness connector
    (to Stop Light Switch Assembly)

  1. Reconnect the stop light switch assembly connector.



NG
REPAIR OR REPLACE HARNESS OR CONNECTOR (STOP LIGHT SWITCH ASSEMBLY - POWER MANAGEMENT CONTROL ECU)
OK


14.INSPECT STOP LIGHT SWITCH ASSEMBLY


    A167698E21

  1. Remove the stop light switch assembly (Click here).

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

    Standard Resistance:
    Tester Connection
    		Switch Condition
    		Specified Condition
    1 - 2
    		Switch pin not pushed
    		Below 1 Ω
    3 - 4
    		Switch pin not pushed
    		10 kΩ or higher
    1 - 2
    		Switch pin pushed
    		10 kΩ or higher
    3 - 4
    		Switch pin pushed
    		Below 1 Ω

    Text in Illustration 
    *a
    		Component without harness connected
    (Stop Light Switch Assembly)
    *b
    		Not pushed
    *c
    		Pushed

  1. Reinstall the stop light switch assembly (Click here).



NG
REPLACE STOP LIGHT SWITCH ASSEMBLY (Click here)
OK


15.CHECK HARNESS AND CONNECTOR (STOP LIGHT SWITCH ASSEMBLY - DRIVING SUPPORT ECU ASSEMBLY)

  1. Disconnect the stop light switch assembly connector.

  1. Disconnect the driving support ECU assembly connector.

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

    Standard Resistance (Check for Open):
    Tester Connection
    		Switch Condition
    		Specified Condition
    A25-3 - H5-28 (ST1-)
    		Always
    		Below 1 Ω
    A25-1 - H5-27 (STP-)
    		Always
    		Below 1 Ω

    Standard Resistance (Check for Open):
    Tester Connection
    		Switch Condition
    		Specified Condition
    A25-3 or H5-28 (ST1-) - Body ground
    		Always
    		10 kΩ or higher
    A25-1 or H5-27 (STP-) - Body ground
    		Always
    		10 kΩ or higher

  1. Reconnect the stop light switch assembly connector.

  1. Reconnect the driving support ECU assembly connector.



NG
REPAIR OR REPLACE HARNESS OR CONNECTOR (STOP LIGHT SWITCH ASSEMBLY - DRIVING SUPPORT ECU ASSEMBLY)
OK


16.CHECK HARNESS AND CONNECTOR

  1. Disconnect the stop light switch assembly connector.

  1. Disconnect the driving support ECU assembly connector.

  1. Disconnect the stop light control relay connector.

  1. Disconnect the brake booster with master cylinder (skid control ECU) connector.

  1. Disconnect the power management control ECU connector.

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

    Standard Resistance (Check for Short):
    Tester Connection
    		Switch Condition
    		Specified Condition
    A25-1 or H5-27 (STP-) - Body ground
    		Always
    		10 kΩ or higher
    A25-1 or A61-33 (STP) - Body ground
    		Always
    		10 kΩ or higher
    A25-1 or A27-5 (STP) - Body ground
    		Always
    		10 kΩ or higher
    A25-1 or A20-23 (STP) - Body ground
    		Always
    		10 kΩ or higher

  1. Reconnect the stop light switch assembly connector.

  1. Reconnect the driving support ECU assembly connector.

  1. Reconnect the power management control ECU connector.

  1. Reconnect the stop light control relay connector.

  1. Reconnect the brake booster with master cylinder (skid control ECU) connector.



NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

REPLACE DRIVING SUPPORT ECU ASSEMBLY (Click here)  

17.CHECK HARNESS AND CONNECTOR (STOP LIGHT SWITCH ASSEMBLY - STOP LIGHT CONTROL RELAY)

  1. Disconnect the stop light switch assembly connector.

  1. Disconnect the stop light control relay connector.

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

    Standard Resistance (Check for Short):
    Tester Connection
    		Switch Condition
    		Specified Condition
    A25-2 or A27-6 (+B) - Body ground
    		Always
    		10 kΩ or higher

  1. Reconnect the stop light switch assembly connector.

  1. Reconnect the stop light control relay connector.



NG
REPAIR OR REPLACE HARNESS OR CONNECTOR (STOP LIGHT SWITCH ASSEMBLY - STOP LIGHT CONTROL RELAY)
OK

REPAIR OR REPLACE HARNESS OR CONNECTOR (STOP LIGHT SWITCH ASSEMBLY - BATTERY)