DYNAMIC RADAR CRUISE CONTROL SYSTEM, Diagnostic DTC:C1A05

DTC Code DTC Name
C1A05 Stop Light Switch Circuit

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

  • Stop light switch assembly

  • Stop light switch circuit

  • Driving support ECU assembly

WIRING DIAGRAM

B001LKSE11

CAUTION / NOTICE / HINT

Tech Tips

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

PROCEDURE


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


    1. Connect the intelligent tester to the DLC3.

    2. Turn the power switch on (IG).

    3. Turn the intelligent tester on.

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

    5. 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

    CHECK HARNESS AND CONNECTOR (STOP LIGHT SWITCH ASSEMBLY - POWER SOURCE) Click here

    OK

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


    1. B001MQ9E01
      Text in Illustration
      *a

      Front view of wire harness connector

      (to Stop Light Control Relay)

      Disconnect the stop light control relay connector.

    2. 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

    3. 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)


    1. B001KT8E01
      Text in Illustration
      *a

      Front view of wire harness connector

      (to Stop Light Control Relay)

      Disconnect the stop light control relay connector.

    2. 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

    3. 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.

    2. Disconnect the stop light switch assembly connector.

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

      Standard Resistance (Check for Open)
      Tester Connection Condition Specified Condition
      A74-2 - A27-5 (STP) Always Below 1 Ω
      Standard Resistance (Check for Short)
      Tester Connection Condition Specified Condition
      A74-2 or A27-5 (STP) - Body ground Always 10 kΩ or higher

    4. Reconnect the stop light switch assembly connector.

    5. 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.

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

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

      Standard Resistance (Check for Open)
      Tester Connection Condition Specified Condition
      A74-2 - A61-6 (STP2) Always Below 1 Ω
      Standard Resistance (Check for Short)
      Tester Connection Condition Specified Condition
      A74-2 or A61-6 (STP2) - Body ground Always 10 kΩ or higher

    4. Reconnect the stop light switch assembly connector.

    5. 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.

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

    3. 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) - A61-33 (STP) Always Below 1 Ω
      A27-5 (STP) - A61-6 (STP2) 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 A61-33 (STP) - Body ground Always 10 kΩ or higher
      A27-5 (STP) or A61-6 (STP2) - Body ground Always 10 kΩ or higher
      A27-9 (ACC) or A61-3 (STP0) - Body ground Always 10 kΩ or higher

    4. Reconnect the stop light control relay connector.

    5. 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) (See page for LHD, Click here for RHD ).


    NEXT

  9. CHECK WHETHER DTC OUTPUT RECORDS (DTC C1A05)


    1. Connect the intelligent tester to the DLC3.

    2. Turn the power switch on (IG).

    3. Clear the DTCs Click here.

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

      Tech Tips

      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.

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

    6. Read the DTCs.

      Result
      Result Proceed to
      DTC is not output A
      DTC C1A05 is output B

    A

    END

    B

  10. REPLACE POWER MANAGEMENT CONTROL ECU


    1. Replace the power management control ECU Click here.


    NEXT

  11. CHECK WHETHER DTC OUTPUT RECORDS (DTC C1A05)


    1. Connect the intelligent tester to the DLC3.

    2. Turn the power switch on (IG).

    3. Clear the DTCs Click here.

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

      Tech Tips

      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.

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

    6. Read the DTCs.

      Result
      Result Proceed to
      DTC is not output A
      DTC C1A05 is output B

    A

    END

    B

    REPLACE DRIVING SUPPORT ECU ASSEMBLY Click here

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


    1. A004VS9E01
      Text in Illustration
      *a

      Front view of wire harness connector

      (to Stop Light Switch Assembly)

      Disconnect the stop light switch assembly connector.

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      A74-1 - Body ground Always 11 to 14 V

    3. Reconnect the stop light switch assembly connector.


    NG

    CHECK HARNESS AND CONNECTOR (STOP LIGHT SWITCH ASSEMBLY - STOP LIGHT CONTROL RELAY) Click here

    OK

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


    1. A004VS9E01
      Text in Illustration
      *a

      Front view of wire harness connector

      (to Stop Light Switch Assembly)

      Disconnect the stop light switch assembly connector.

    2. Turn the power switch on (IG).

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      A74-5 - Body ground Power switch on (IG) 11 to 14 V

    4. 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


    1. Remove the stop light switch assembly Click here.

    2. Inspect 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.

    2. Disconnect the driving support ECU assembly connector.

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

      Standard Resistance (Check for Open)
      Tester Connection Switch Condition Specified Condition
      A74-4 - H5-28 (ST1-) Always Below 1 Ω
      A74-2 - H5-27 (STP-) Always Below 1 Ω
      Standard Resistance (Check for Open)
      Tester Connection Switch Condition Specified Condition
      A74-4 or H5-28 (ST1-) - Body ground Always 10 kΩ or higher
      A74-2 or H5-27 (STP-) - Body ground Always 10 kΩ or higher

    4. Reconnect the stop light switch assembly connector.

    5. 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.

    2. Disconnect the driving support ECU assembly connector.

    3. Disconnect the stop light control relay connector.

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

    5. Disconnect the power management control ECU connector.

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

      Standard Resistance (Check for Short)
      Tester Connection Switch Condition Specified Condition
      A74-2 or H5-27 (STP-) - Body ground Always 10 kΩ or higher
      A74-2 or A61-6 (STP2) - Body ground Always 10 kΩ or higher
      A74-2 or A27-5 (STP) - Body ground Always 10 kΩ or higher
      A74-2 or A20-23 (STP) - Body ground Always 10 kΩ or higher

    7. Reconnect the stop light switch assembly connector.

    8. Reconnect the driving support ECU assembly connector.

    9. Reconnect the power management control ECU connector.

    10. Reconnect the stop light control relay connector.

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


    OK

    REPLACE DRIVING SUPPORT ECU ASSEMBLY Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

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


    1. Disconnect the stop light switch assembly connector.

    2. Disconnect the stop light control relay connector.

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

      Standard Resistance (Check for Short)
      Tester Connection Switch Condition Specified Condition
      A74-1 or A27-6 (+B) - Body ground Always 10 kΩ or higher

    4. Reconnect the stop light switch assembly connector.

    5. Reconnect the stop light control relay connector.


    OK

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

    NG

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