DYNAMIC RADAR CRUISE CONTROL SYSTEM, Diagnostic DTC:C1A4B

DTC Code DTC Name
C1A4B Stop Light Relay Circuit

DESCRIPTION

The brake booster with master cylinder assembly (skid control ECU) sends a stop light operation signal to the stop light control ECU assembly. When the brake booster with master cylinder assembly (skid control ECU) detects a malfunction in the stop light circuit, the driving support ECU assembly stores DTC C1A4B.

Vehicle Condition
Pattern 1 Pattern 2
Diagnosis Condition IG1 terminal voltage is 11 to 14 V ○ ○
When the vehicle speed is approximately 50 km/h (30 mph) or more, the cruise control switch (ON/OFF) is on ○ ○
Stop Light illumination output (STPO) ON ○ -
Stop Light illumination output (STPO) OFF - ○
Malfunction Status No signal input to STP2 terminal ○ -
Signals input to STP and STP2 terminals do not match - ○
Malfunction Time 0.3 seconds or more 0.3 seconds or more
Number of Trips - -
DTC No. Detection Item DTC Detection Condition Trouble Area
C1A4B Stop Light Relay Circuit

Either of the following conditions is met:


  • When the vehicle speed is approximately 50 km/h (30 mph) or more, the cruise control switch (ON/OFF) is on, the IG1 terminal voltage is between 11 and 14 V and the stop light illumination output signal (STPO) is output, the signal is not received at terminal STP2 for 0.3 seconds or more. (Pattern 1)

  • When the vehicle speed is approximately 50 km/h (30 mph) or more, the cruise control switch (ON/OFF) is on, the IG1 terminal voltage is between 11 and 14 V and the stop light illumination output signal (STPO) is not output, the signals received at terminals STP and STP2 are different for 0.3 seconds or more. (Pattern 2)

  • Brake actuator assembly (skid control ECU)

  • Stop light control ECU assembly

  • Rear combination light assembly LH

  • Rear combination light assembly RH

  • Center stop light assembly

  • Harness or connector

WIRING DIAGRAM

B002JCZE05

CAUTION / NOTICE / HINT

Note


  • First perform the communication function inspections in How to Proceed with Troubleshootingto confirm that there are no CAN communication malfunctions before troubleshooting.

    Click here

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

  • When replacing the brake booster with master cylinder assembly (skid control ECU), perform zero point calibration.

    Click here

PROCEDURE


  1. CHECK TERMINAL VOLTAGE (STP, STPO AND STP2 TERMINAL)


    1. Turn the power swich off.

    2. B002J5VC03
      *a

      Front view of wire harness connector

      (to Brake Booster with Master Cylinder Assembly [Skid Control ECU])

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

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      A57-6 (STP2) - Body ground Brake pedal depressed 11 to 14 V
      Brake pedal released Below 1.5 V
      A57-3 (STPO) - Body ground Always 11 to 14 V
      A57-33 (STP) - Body ground Brake pedal depressed 11 to 14 V
      Brake pedal released Below 1.5 V
      Result
      Result Proceed to
      All terminal voltage is normal A
      Only STP terminal voltage abnormal B
      Only STPO terminal voltage abnormal C
      Only STP2 terminal voltage abnormal D
      STPO terminal and STP2 terminal voltage abnormal E

    B

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    C

    CHECK HARNESS AND CONNECTOR (BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY [SKID CONTROL ECU] - STOP LIGHT CONTROL ECU ASSEMBLY) Click here

    D

    CHECK TERMINAL VOLTAGE (STP2 TERMINAL) Click here

    E

    CHECK STOP LIGHT CONTROL ECU ASSEMBLY POWER SOURCE CIRCUIT Click here

    A

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


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

    2. Perform "Active Test" according to the display on the GTS.


      Chassis > ABS/VSC/TRC > Active Test
      Tester Display Measurement Item Control Range Diagnostic Note
      Stop Light Relay Stop light control ECU assembly (stop light control relay) ECU (Relay) ON/OFF Stop lights come on

      Chassis > ABS/VSC/TRC > Active Test
      Tester Display
      Stop Light Relay
      OK
      Stop light turns ON/OFF in response to the GTS operation
      Result
      Proceed to
      OK
      NG

    NG

    INSPECT BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY (SKID CONTROL ECU) Click here

    OK

  3. CHECK FOR DTC


    1. Clear the DTCs.

      Click here


      Powertrain > Radar Cruise > Clear DTCs

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

    3. Perform "Active Test" according to the display on the GTS.


      Chassis > ABS/VSC/TRC > Active Test
      Tester Display Measurement Item Control Range Diagnostic Note
      Stop Light Relay Stop light control ECU assembly (stop light control relay) ECU (Relay) ON/OFF Stop lights come on

      Chassis > ABS/VSC/TRC > Active Test
      Tester Display
      Stop Light Relay

    4. Check for DTCs.

      Click here


      Powertrain > Radar Cruise > Trouble Codes
      Result
      Result Proceed to
      DTC C1A4B is output A
      DTC C1A4B is not output B

    A

    REPLACE BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY (SKID CONTROL ECU) for LHD: Click here
    REPLACE BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY (SKID CONTROL ECU) for RHD: Click here

    B

    USE SIMULATION METHOD TO CHECK Click here

  4. INSPECT BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY (SKID CONTROL ECU)


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

    2. Perform "Active Test" according to the display on the GTS.


      Chassis > ABS/VSC/TRC > Active Test
      Tester Display Measurement Item Control Range Diagnostic Note
      Stop Light Relay Stop light control ECU assembly (stop light control relay) ECU (Relay) ON/OFF Stop lights come on

      Chassis > ABS/VSC/TRC > Active Test
      Tester Display
      Stop Light Relay
    3. B002HYNC28
      *a

      Component with harness connected

      (Stop Light Control ECU Assembly)

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      A3-9 (ACC) - Body ground Active test is ON Below 1.5 V
      Result
      Proceed to
      OK
      NG

    OK

    REPLACE STOP LIGHT CONTROL ECU ASSEMBLY for LHD: Click here
    REPLACE STOP LIGHT CONTROL ECU ASSEMBLY for RHD: Click here

    NG

    REPLACE BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY (SKID CONTROL ECU) for LHD: Click here
    REPLACE BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY (SKID CONTROL ECU) for RHD: Click here

  5. CHECK HARNESS AND CONNECTOR (BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY [SKID CONTROL ECU] - STOP LIGHT CONTROL ECU ASSEMBLY)


    1. Turn the power switch off.

    2. Disconnect the A57 brake booster with master cylinder assembly (skid control ECU) connector.

    3. Disconnect the A3 stop light control ECU assembly connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      A57-3 (STPO) - A3-9 (ACC) Always Below 1 Ω
      Result
      Proceed to
      OK
      NG

    OK

    REPLACE STOP LIGHT CONTROL ECU ASSEMBLY for LHD: Click here
    REPLACE STOP LIGHT CONTROL ECU ASSEMBLY for RHD: Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

  6. CHECK TERMINAL VOLTAGE (STP2 TERMINAL)


    1. Turn the power switch off.

    2. B002J5VC04
      *a

      Front view of wire harness connector

      (to Brake Booster with Master Cylinder Assembly [Skid Control ECU])

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

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      A57-6 (STP2) - Body ground Brake pedal released Below 1.5 V
      Result
      Proceed to
      OK
      NG

    NG

    CHECK HARNESS AND CONNECTOR (BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY [SKID CONTROL ECU] - STOP LIGHT CONTROL ECU ASSEMBLY) Click here

    OK

  7. CHECK HARNESS AND CONNECTOR (BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY [SKID CONTROL ECU] - REAR COMBINATION LIGHT ASSEMBLY LH)


    1. Turn the power switch off.

    2. Disconnect the A57 brake booster with master cylinder assembly (skid control ECU) connector.

    3. Disconnect the Q16 rear combination light assembly LH connector.

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      A57-6 (STP2) - Body ground Brake pedal depressed 11 to 14 V
      Result
      Proceed to
      OK
      NG

    OK

    REPLACE REAR COMBINATION LIGHT ASSEMBLY LH Click here

    NG

  8. CHECK HARNESS AND CONNECTOR (BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY [SKID CONTROL ECU] - REAR COMBINATION LIGHT ASSEMBLY RH)


    1. Turn the power switch off.

    2. Disconnect the A57 brake booster with master cylinder assembly (skid control ECU) connector.

    3. Disconnect the Q16 rear combination light assembly LH connector.

    4. Disconnect the P13 rear combination light assembly RH connector.

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      A57-6 (STP2) - Body ground Brake pedal depressed 11 to 14 V
      Result
      Proceed to
      OK
      NG

    OK

    REPLACE REAR COMBINATION LIGHT ASSEMBLY RH Click here

    NG

  9. CHECK HARNESS AND CONNECTOR (BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY [SKID CONTROL ECU] - CENTER STOP LIGHT ASSEMBLY)


    1. Turn the power switch off.

    2. Disconnect the A57 brake booster with master cylinder assembly (skid control ECU) connector.

    3. Disconnect the Q16 rear combination light assembly LH connector.

    4. Disconnect the P13 rear combination light assembly RH connector.

    5. Disconnect the e1 center stop light assembly connector.

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      A57-6 (STP2) - Body ground Brake pedal depressed 11 to 14 V
      Result
      Proceed to
      OK
      NG

    OK

    REPLACE CENTER STOP LIGHT ASSEMBLY Click here

    NG

    CHECK HARNESS AND CONNECTOR (BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY [SKID CONTROL ECU] - STOP LIGHT CONTROL ECU ASSEMBLY) Click here

  10. CHECK HARNESS AND CONNECTOR (BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY [SKID CONTROL ECU] - STOP LIGHT CONTROL ECU ASSEMBLY)


    1. Turn the power switch off.

    2. Disconnect the A57 brake booster with master cylinder assembly (skid control ECU) connector.

    3. Disconnect the A3 stop light control ECU assembly connector.

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      A57-6 (STP2) - Body ground Brake pedal released Below 1.5 V
      Result
      Proceed to
      OK
      NG

    OK

    REPLACE STOP LIGHT CONTROL ECU ASSEMBLY for LHD: Click here
    REPLACE STOP LIGHT CONTROL ECU ASSEMBLY for RHD: Click here

    NG

    CHECK HARNESS AND CONNECTOR (BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY [SKID CONTROL ECU] - REAR COMBINATION LIGHT ASSEMBLY LH) Click here

  11. CHECK HARNESS AND CONNECTOR (BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY [SKID CONTROL ECU] - STOP LIGHT CONTROL ECU ASSEMBLY)


    1. Turn the power switch off.

    2. Disconnect the A57 brake booster with master cylinder assembly (skid control ECU) connector.

    3. Disconnect the Q16 rear combination light assembly LH connector.

    4. Disconnect the P13 rear combination light assembly RH connector.

    5. Disconnect the e1 center stop light assembly connector.

    6. Disconnect the A3 stop light control ECU assembly connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      A3-5 (STP) - A57-33 (STP) Always Below 1 Ω
      A3-1 (OUT) - A57-6 (STP2) Always Below 1 Ω
      A3-1 (OUT) or A57-6 (STP2) - Body ground Always 10 kΩ or higher
      Result
      Proceed to
      OK
      NG

    OK

    REPLACE STOP LIGHT CONTROL ECU ASSEMBLY for LHD: Click here
    REPLACE STOP LIGHT CONTROL ECU ASSEMBLY for RHD: Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

  12. CHECK HARNESS AND CONNECTOR (BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY [SKID CONTROL ECU] - REAR COMBINATION LIGHT ASSEMBLY LH)


    1. Turn the power switch off.

    2. Disconnect the A57 brake booster with master cylinder assembly (skid control ECU) connector.

    3. Disconnect the A3 stop light control ECU assembly connector.

    4. Disconnect the Q16 rear combination light assembly LH connector.

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      A57-6 (STP2) - Body ground Brake pedal released Below 1.5 V
      Result
      Proceed to
      OK
      NG

    OK

    REPLACE REAR COMBINATION LIGHT ASSEMBLY LH Click here

    NG

  13. CHECK HARNESS AND CONNECTOR (BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY [SKID CONTROL ECU] - REAR COMBINATION LIGHT ASSEMBLY RH)


    1. Turn the power switch off.

    2. Disconnect the A57 brake booster with master cylinder assembly (skid control ECU) connector.

    3. Disconnect the A3 stop light control ECU assembly connector.

    4. Disconnect the Q16 rear combination light assembly LH connector.

    5. Disconnect the P13 rear combination light assembly RH connector.

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      A57-6 (STP2) - Body ground Brake pedal released Below 1.5 V
      Result
      Proceed to
      OK
      NG

    OK

    REPLACE REAR COMBINATION LIGHT ASSEMBLY RH Click here

    NG

    CHECK HARNESS AND CONNECTOR (BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY [SKID CONTROL ECU] - CENTER STOP LIGHT ASSEMBLY) Click here

  14. CHECK STOP LIGHT CONTROL ECU ASSEMBLY POWER SOURCE CIRCUIT


    1. Turn the power switch off.

    2. B002IYCC24
      *a

      Front view of wire harness connector

      (to Stop Light Control ECU Assembly)

      Disconnect the stop light control ECU assembly connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      A3-8 (GND) - Body ground Always Below 1 Ω

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

      Standard Voltage
      Tester Connection Switch Condition Specified Condition
      A3-6 (+B) - Body ground Power swich off 11 to 14 V
      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  15. CHECK HARNESS AND CONNECTOR (BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY [SKID CONTROL ECU] - STOP LIGHT CONTROL ECU ASSEMBLY)


    1. Turn the power switch off.

    2. Disconnect the A57 brake booster with master cylinder assembly (skid control ECU) connector.

    3. Disconnect the A3 stop light control ECU assembly connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      A57-3 (STPO) - A3-9 (ACC) Always Below 1 Ω
      Result
      Proceed to
      OK
      NG

    OK

    REPLACE STOP LIGHT CONTROL ECU ASSEMBLY for LHD: Click here
    REPLACE STOP LIGHT CONTROL ECU ASSEMBLY for RHD: Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

  16. CHECK HARNESS AND CONNECTOR (BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY [SKID CONTROL ECU] - CENTER STOP LIGHT ASSEMBLY)


    1. Turn the power switch off.

    2. Disconnect the A57 brake booster with master cylinder assembly (skid control ECU) connector.

    3. Disconnect the A3 stop light control ECU assembly connector.

    4. Disconnect the Q16 rear combination light assembly LH connector.

    5. Disconnect the P13 rear combination light assembly RH connector.

    6. Disconnect the e1 center stop light assembly connector.

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      A57-6 (STP2) - Body ground Brake pedal released Below 1.5 V
      Result
      Proceed to
      OK
      NG

    OK

    REPLACE CENTER STOP LIGHT ASSEMBLY Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR