Toyota Tacoma manuals

Toyota Tacoma (2015-2018) Service Manual: Skid Control Buzzer Circuit (C1A4A)

Toyota Tacoma (2015-2018) Service Manual / Pre-collision / Pre-collision System / 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.

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

WIRING DIAGRAM

CAUTION / NOTICE / HINT

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.

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

Click here NOTICE:

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 status

ON or OFF

ON: Skid control buzzer sounding

OFF: Skid control buzzer 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 skid control buzzer connector.

*a

Front view of wire harness connector

(to Skid Control Buzzer)

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

Standard Voltage:

Tester Connection

Switch Condition

Specified Condition

N38-2 (IG1) - Body ground

Ignition switch ON

11 to 14 V

Ignition switch off

Below 1 V

(c) Connect the skid control buzzer connector.

NG

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

3.

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

(a) Disconnect the N38 skid control buzzer connector.

(b) Disconnect the F46 forward recognition camera connector.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

N38-1 (BZ) - F46-8 (BZ)

Always

Below 1 Ω

N38-1 (BZ) or F46-8 (BZ) - Body ground

Always

10 kΩ or higher

(d) Connect the F46 forward recognition camera connector.

(e) Connect the N38 skid control buzzer connector.

OK

GO TO STEP 6

NG

4.

REPAIR OR REPLACE HARNESS OR CONNECTOR (SKID CONTROL BUZZER - 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.

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

Click here NOTICE:

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 status

ON or OFF

ON: Skid control buzzer sounding

OFF: Skid control buzzer 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 (CONFIRM BUZZER OPERATION)

(a) Turn the ignition switch to ON.

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

Result

Proceed to

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

A

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

B
B

GO TO STEP 8

A

7.

INSPECT SKID CONTROL BUZZER (UNIT INSPECTION)

(a) Remove the skid control buzzer.

Click here (b) Inspect the skid control buzzer.

(b) Inspect the skid control buzzer.

Click here

Result

Proceed to

Skid control buzzer is abnormal

A

Skid control buzzer is normal

B
B

GO TO STEP 9

A

8.

REPLACE SKID CONTROL BUZZER

(a) Replace the skid control buzzer.

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.

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

Click here NOTICE:

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 status

ON or OFF

ON: Skid control buzzer sounding

OFF: Skid control buzzer 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.

(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.

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

Click here NOTICE:

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 status

ON or OFF

ON: Skid control buzzer sounding

OFF: Skid control buzzer 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.

(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

Body Electrical > Pre-Collision 2 > Clear DTCs
NEXT

END (MILLIMETER WAVE RADAR SENSOR ASSEMBLY WAS DEFECTIVE)
Brake Control Signal Mismatch (C1A69)
DESCRIPTION The skid control ECU (master cylinder solenoid)*1 or skid control ECU (brake actuator assembly)*2 sends signals to the millimeter wave radar sensor assembly according to the brake con ...

Stop Light Relay Circuit (C1A4B)
DESCRIPTION The skid control ECU (master cylinder solenoid)*1 or skid control ECU (brake actuator assembly)*2 sends a stop light operation request signal to the stop light relay (stop light switc ...

Other materials:

Data List / Active Test
DATA LIST / ACTIVE TEST NOTICE: In the table below, the values listed under "Normal Condition" are reference values. Do not depend solely on these reference values when deciding whether a part is faulty or not. HINT: Using the Techstream to read the Data List allows the values or s ...

Operation Check
OPERATION CHECK 1. CHECK AUTO OPERATION NOTICE: Make sure that initialization has been completed before inspection (See page ). The sliding roof auto operation can be customized. Make sure that the auto operation is ON (See page ). HINT: When pressing the switch for ...

Vehicle Speed Signal Malfunction (B2282,B2283)
DESCRIPTION DTC B2282 is stored when the vehicle speed signal sent by the combination meter assembly via direct line and the vehicle speed signal sent via CAN communication do not match. DTC B2283 is stored when a malfunction in the vehicle speed sensor is detected. HINT: When the cable is d ...

© 2011-2025 Copyright www.ttguide.net