Toyota CH-R 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 pre-collision city buzzer.

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

DTC Detection Conditions:

		Vehicle Condition
		Pattern 1	Pattern 2
Diagnosis Condition	When the ignition switch is ON and the pre-collision alarm is operating.	○	○
Malfunction Status	A buzzer request signal is sent to the pre-collision city buzzer but the buzzer does not sound.	○	-
	A buzzer request signal is not sent to the pre-collision city buzzer but the buzzer sounds.	-	○
Detection Time		0.3 seconds	0.3 seconds
Number of Trips		1 trip	1 trip

HINT:

DTC will be output when conditions for either of the patterns in the table above are met.

WIRING DIAGRAM

CAUTION / NOTICE / HINT

PROCEDURE

1.	CHECK FOR DTCs (PRE-COLLISION SYSTEM)

(a) Clear the DTCs.

Click here

Body Electrical > Pre-Collision 2 > Clear DTCs

(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 > Active Test

Tester Display	Measurement Item	Control Range	Diagnostic Note
PCS Collision Alarm Buzzer	Pre-collision city buzzer	ON / OFF	Test possible with ignition switch to ON Vehicle condition: Vehicle stopped

Body Electrical > Pre-Collision 2 > Active Test

Tester Display
PCS Collision Alarm Buzzer

(c) Check for DTCs.

Click here

Body Electrical > Pre-Collision 2 > Trouble Codes

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 pre-collision city buzzer connector.

*a Front view of wire harness connector (to Pre-collision City Buzzer)

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

Standard Voltage:

Tester Connection	Switch Condition	Specified Condition
F54-2 (IG1) - Body ground	Ignition switch ON	11 to 14 V
	Ignition switch off	Below 1 V

(c) Connect the F54 pre-collision city buzzer connector.

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR (PRE-COLLISION CITY BUZZER - BATTERY)

OK

3.	CHECK HARNESS AND CONNECTOR (PRE-COLLISION CITY BUZZER - FORWARD RECOGNITION CAMERA)

(a) Disconnect the F54 pre-collision city buzzer connector.

(b) Disconnect the R5 forward recognition camera connector.

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
F54-1 (BZ) - R5-8 (BZ)	Always	Below 1 Ω
F54-1 (BZ) or R5-8 (BZ) - Body ground	Always	10 kΩ or higher

(d) Connect the R5 forward recognition camera connector.

(e) Connect the F54 pre-collision city buzzer connector.

OK

GO TO STEP 6

NG

4.	REPAIR OR REPLACE HARNESS OR CONNECTOR (PRE-COLLISION CITY 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

Body Electrical > Pre-Collision 2 > Clear DTCs

(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 > Active Test

Tester Display	Measurement Item	Control Range	Diagnostic Note
PCS Collision Alarm Buzzer	Pre-collision city buzzer	ON / OFF	Test possible with ignition switch to ON Vehicle condition: Vehicle stopped

Body Electrical > Pre-Collision 2 > Active Test

Tester Display
PCS Collision Alarm Buzzer

(c) Check for DTCs.

Click here

Body Electrical > Pre-Collision 2 > Trouble Codes

Result	Proceed to
DTC C1A4A is not output	A
DTC C1A4A is output	B

A

END

B

6.	INSPECT PRE-COLLISION CITY BUZZER (CONFIRM BUZZER OPERATION)

(a) Turn the ignition switch to ON.

(b) Check if the pre-collision city buzzer is sounding.

Result	Proceed to
The pre-collision city buzzer does not sound when the ignition switch is ON	A
The pre-collision city buzzer sounds continuously when the ignition switch is ON	B

B

GO TO STEP 8

A

7.	INSPECT PRE-COLLISION CITY BUZZER (UNIT INSPECTION)

(a) Remove the pre-collision city buzzer.

Click here

(b) Inspect the pre-collision city buzzer.

Click here

Result	Proceed to
Pre-collision city buzzer is abnormal	A
Pre-collision city buzzer is normal	B

B

GO TO STEP 9

A

8.	REPLACE PRE-COLLISION CITY BUZZER

(a) Replace the pre-collision city buzzer.

Click here

NEXT

9.	CHECK FOR DTCs (PRE-COLLISION SYSTEM)

(a) Clear the DTCs.

Click here

Body Electrical > Pre-Collision 2 > Clear DTCs

(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 > Active Test

Tester Display	Measurement Item	Control Range	Diagnostic Note
PCS Collision Alarm Buzzer	Pre-collision city buzzer	ON / OFF	Test possible with ignition switch to ON Vehicle condition: Vehicle stopped

Body Electrical > Pre-Collision 2 > Active Test

Tester Display
PCS Collision Alarm Buzzer

(c) Check for DTCs.

Click here

Body Electrical > Pre-Collision 2 > Trouble Codes

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

Body Electrical > Pre-Collision 2 > Clear DTCs

(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 > Active Test

Tester Display	Measurement Item	Control Range	Diagnostic Note
PCS Collision Alarm Buzzer	Pre-collision city buzzer	ON / OFF	Test possible with ignition switch to ON Vehicle condition: Vehicle stopped

Body Electrical > Pre-Collision 2 > Active Test

Tester Display
PCS Collision Alarm Buzzer

(c) Check for DTCs.

Click here

Body Electrical > Pre-Collision 2 > Trouble Codes

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)