Toyota Tundra Service Manual: Skid Control Buzzer Circuit (C1A4A)

DESCRIPTION

The millimeter wave radar sensor assembly is connected to the forward recognition camera via CAN communication.

The millimeter wave radar sensor assembly operates the pre-collision alarm by sending a buzzer request signal to the skid control buzzer assembly.

If the millimeter wave radar sensor assembly detects a malfunction in the skid control buzzer assembly circuit, it stores DTC C1A4A.

DTC No.

Detection Item

DTC Detection Condition

Trouble Area

C1A4A

Skid Control Buzzer Circuit

When the ignition switch is ON and the pre-collision alarm is operating, either of the following conditions is met:

  • A buzzer request signal is sent to the skid control buzzer assembly but the buzzer does not sound for 0.3 seconds or more.
  • A buzzer request signal is not sent to the skid control buzzer assembly but the buzzer sounds for 0.3 seconds or more.
  • Skid control buzzer assembly
  • Forward recognition camera
  • Millimeter wave radar sensor assembly
  • Wire harness or connector

WIRING DIAGRAM

CAUTION / NOTICE / HINT

NOTICE:

  • Inspect the fuses for circuits related to this system before performing the following procedure.
  • When replacing the millimeter wave radar sensor assembly, always replace it with a new one.
  • When the millimeter wave radar sensor assembly is replaced with a new one, adjustment of the radar sensor beam axis must be performed.

    Click here

  • If the forward recognition camera has been replaced with a new one, be sure to perform forward recognition axis adjustment.

    Click here

  • When a malfunction occurs in the communication line to the forward recognition camera, U023A and/or U1002 is output. If a DTC related to the CAN communication line is output, first troubleshoot the CAN communication line.

    Click here

PROCEDURE

1.

CHECK FOR DTCs (PRE-COLLISION SYSTEM)

(a) Clear the DTCs.

Click here

(b) Perform the Active Test according to the display on the Techstream.

Click here

NOTICE:

Perform the Active Test for 1 second or more.

HINT:

Performing the Active Test for 1 second or more causes DTC C1A4A to be stored if the DTC detection conditions are met.

Body Electrical > Pre-Collision 2 > Data List

Tester Display

Measurement Item

Range

Normal Condition

Diagnostic Note

PCS Crash Alarm Buzzer

Skid control buzzer assembly status

ON or OFF

ON: Skid control buzzer assembly sounding

OFF: Skid control buzzer assembly not sounding

-

(c) Check for DTCs.

Click here

Result

Proceed to

DTC C1A4A is not output

A

DTC C1A4A is output

B

A

USE SIMULATION METHOD TO CHECK

B

2.

CHECK TERMINAL VOLTAGE

(a) Disconnect the J167 skid control buzzer assembly connector.

*a

Front view of wire harness connector

(to Skid Control Buzzer Assembly)

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

Standard Voltage:

Tester Connection

Switch Condition

Specified Condition

J167-2 (IG1) - Body ground

Ignition switch ON

11 to 14 V

Ignition switch off

Below 1 V

(c) Connect the J167 skid control buzzer assembly connector.

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR (SKID CONTROL BUZZER ASSEMBLY - BATTERY)

OK

3.

CHECK HARNESS AND CONNECTOR (SKID CONTROL BUZZER ASSEMBLY - FORWARD RECOGNITION CAMERA)

(a) Disconnect the J167 skid control buzzer assembly connector.

(b) Disconnect the W9 forward recognition camera connector.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

J167-1 (BZ) - W9-8 (BZ)

Always

Below 1 Ω

J167-1 (BZ) or W9-8 (BZ) - Body ground

Always

10 kΩ or higher

(d) Connect the W9 forward recognition camera connector.

(e) Connect the J167 skid control buzzer assembly connector.

OK

GO TO STEP 6

NG

4.

REPAIR OR REPLACE HARNESS OR CONNECTOR (SKID CONTROL BUZZER ASSEMBLY - FORWARD RECOGNITION CAMERA)

(a) Repair or replace the harness or connector.

NEXT

5.

CHECK FOR DTCs (PRE-COLLISION SYSTEM)

(a) Clear the DTCs.

Click here

(b) Perform the Active Test according to the display on the Techstream.

Click here

NOTICE:

Perform the Active Test for 1 second or more.

HINT:

Performing the Active Test for 1 second or more causes DTC C1A4A to be stored if the DTC detection conditions are met.

Body Electrical > Pre-Collision 2 > Data List

Tester Display

Measurement Item

Range

Normal Condition

Diagnostic Note

PCS Crash Alarm Buzzer

Skid control buzzer assembly status

ON or OFF

ON: Skid control buzzer assembly sounding

OFF: Skid control buzzer assembly not sounding

-

(c) Check for DTCs.

Click here

Result

Proceed to

DTC C1A4A is not output

A

DTC C1A4A is output

B

A

END

B

6.

INSPECT SKID CONTROL BUZZER ASSEMBLY (CONFIRM BUZZER OPERATION)

(a) Turn the ignition switch to ON.

(b) Check if the skid control buzzer assembly is sounding.

Result

Proceed to

The skid control buzzer assembly does not sound when the ignition switch is ON

A

The skid control buzzer assembly sounds continuously when the ignition switch is ON

B

B

GO TO STEP 8

A

7.

INSPECT SKID CONTROL BUZZER ASSEMBLY (UNIT INSPECTION)

(a) Remove the skid control buzzer assembly.

Click here

(b) Inspect the skid control buzzer assembly.

Click here

Result

Proceed to

Skid control buzzer assembly is abnormal

A

Skid control buzzer assembly is normal

B

B

GO TO STEP 9

A

8.

REPLACE SKID CONTROL BUZZER ASSEMBLY

(a) Replace the skid control buzzer assembly.

Click here

NEXT

9.

CHECK FOR DTCs (PRE-COLLISION SYSTEM)

(a) Clear the DTCs.

Click here

(b) Perform the Active Test according to the display on the Techstream.

Click here

NOTICE:

Perform the Active Test for 1 second or more.

HINT:

Performing the Active Test for 1 second or more causes DTC C1A4A to be stored if the DTC detection conditions are met.

Body Electrical > Pre-Collision 2 > Data List

Tester Display

Measurement Item

Range

Normal Condition

Diagnostic Note

PCS Crash Alarm Buzzer

Skid control buzzer assembly status

ON or OFF

ON: Skid control buzzer assembly sounding

OFF: Skid control buzzer assembly not sounding

-

(c) Check for DTCs.

Click here

Result

Proceed to

DTC C1A4A is not output

A

DTC C1A4A is output

B

A

END

B

10.

REPLACE FORWARD RECOGNITION CAMERA

(a) Replace the forward recognition camera.

Click here

(b) Perform forward recognition axis adjustment.

Click here

NEXT

11.

CHECK FOR DTCs (PRE-COLLISION SYSTEM)

(a) Clear the DTCs.

Click here

(b) Perform the Active Test according to the display on the Techstream.

Click here

NOTICE:

Perform the Active Test for 1 second or more.

HINT:

Performing the Active Test for 1 second or more causes DTC C1A4A to be stored if the DTC detection conditions are met.

Body Electrical > Pre-Collision 2 > Data List

Tester Display

Measurement Item

Range

Normal Condition

Diagnostic Note

PCS Crash Alarm Buzzer

Skid control buzzer assembly status

ON or OFF

ON: Skid control buzzer assembly sounding

OFF: Skid control buzzer assembly not sounding

-

(c) Check for DTCs.

Click here

Result

Proceed to

DTC C1A4A is not output

A

DTC C1A4A is output

B

A

END (FORWARD RECOGNITION CAMERA WAS DEFECTIVE)

B

12.

REPLACE MILLIMETER WAVE RADAR SENSOR ASSEMBLY

(a) Replace the millimeter wave radar sensor assembly.

Click here

(b) Adjust the millimeter wave radar sensor assembly.

Click here

NEXT

13.

CLEAR DTC (PRE-COLLISION SYSTEM)

(a) Clear the DTCs.

Click here

Body Electrical > Pre-Collision 2 > Clear DTCs
NEXT

END (MILLIMETER WAVE RADAR SENSOR ASSEMBLY WAS DEFECTIVE)

    Vehicle Information Not Obtained (C1A02)

    Stop Light Relay Circuit (C1A4B)

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