Toyota Tacoma (2015-2018) 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.

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

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 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.

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 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.

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.

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 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.

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 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.

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)