Lexus RX (RX 350L, RX450h) 2016-2026 Repair Manual: Buzzer Circuit Short to Ground or Open (C1A4A14)

Lexus RX (RX 350L, RX450h) 2016-2026 Repair Manual / Engine & Hybrid System / Cruise Control / Front Camera System / Buzzer Circuit Short to Ground or Open (C1A4A14)

DESCRIPTION

If the forward recognition camera detects an open or short to ground in the buzzer circuit, it will store DTC C1A4A14.

DTC No.

Detection Item

DTC Detection Condition

Trouble Area

C1A4A14

Buzzer Circuit Short to Ground or Open

The forward recognition camera detects an open or short to ground in the buzzer circuit for 2 seconds or more.
  • Skid control buzzer assembly
  • Forward recognition camera
  • 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 forward recognition camera, always replace it with a new one. If a forward recognition camera which was installed to another vehicle is used, the information stored in the forward recognition camera will not match the information from the vehicle. As a result, a DTC may be stored.
  • If the forward recognition camera has been replaced with a new one, be sure to perform forward recognition camera adjustment.

    HINT:

    Forward recognition camera adjustment can be performed by using either One Time Recognition or Sequential Recognition.

    One Time Recognition: Click here

    Sequential Recognition: Click here

PROCEDURE

1.

CHECK FOR DTCs

(a) Clear the DTCs.

Chassis > Front Recognition Camera > Clear DTCs

(b) Make sure that the DTC detection conditions are met.

HINT:

If the detection conditions are not met, the system cannot detect the malfunction.

(c) Check for DTCs.

Chassis > Front Recognition Camera > Trouble Codes

Result

Proceed to

DTC C1A4A14 is not output

A

DTC C1A4A14 is output

B
A

USE SIMULATION METHOD TO CHECK

B

2.

CHECK HARNESS AND CONNECTOR (SKID CONTROL BUZZER ASSEMBLY POWER SOURCE CIRCUIT)

*a

Front view of wire harness connector

(to Skid Control Buzzer Assembly)

(a) Disconnect the A15 skid control buzzer assembly connector.

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

Standard Voltage:

Tester Connection

Switch Condition

Specified Condition

A15-2 (IG1) - Body ground

Engine switch on (IG)

8 to 16 V

Engine switch off

Below 1 V
NG

REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

3.

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

(a) Disconnect the U14 forward recognition camera connector.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

A15-1 (BZ) - U14-8 (BZ)

Always

Below 1 Ω

A15-1 (BZ) or U14-8 (BZ) - Body ground

Always

10 kΩ higher
NG

REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

4.

INSPECT SKID CONTROL BUZZER ASSEMBLY

(a) Remove the skid control buzzer assembly.

Click here

(b) Inspect the skid control buzzer assembly.

Click here

OK

REPLACE FORWARD RECOGNITION CAMERA

NG

REPLACE SKID CONTROL BUZZER ASSEMBLY

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