Lexus RX (RX 350L, RX450h) 2016-2025 Repair Manual: Front Sensor Communication Malfunction (C1AEC)

Lexus RX (RX 350L, RX450h) 2016-2025 Repair Manual / Audio & Visual & Telematics / Park Assist / Monitoring / Intuitive Parking Assist System (w/ Intelligent Clearance Sonar System) / Front Sensor Communication Malfunction (C1AEC)

DESCRIPTION

This DTC is stored when there is an open or short circuit in the communication line between the front sensors and the ECU, or when there is a malfunction in a front sensor.

DTC No.

Detection Item

DTC Detection Condition

Trouble Area

C1AEC

Front Sensor Communication Malfunction

An open or short circuit in the communication line between the front sensors and ECU or a malfunction in a front sensor during initialization mode after the engine switch is turned on (IG).
  • Front ultrasonic sensor circuit
  • Harness or connector
  • Clearance warning ECU assembly

WIRING DIAGRAM

PROCEDURE

1.

INITIALIZE FRONT CENTER ULTRASONIC SENSOR AND FRONT CORNER ULTRASONIC SENSOR

(a) Initialize the front center ultrasonic sensor and front corner ultrasonic sensor.

Click here

NEXT

2.

CHECK DTC OUTPUT (C1AEC)

(a) Check for DTCs.

Body Electrical > Advanced Parking Guidance/ICS/Intuitive P/A > Trouble Codes

(b) Clear the DTCs.

Body Electrical > Advanced Parking Guidance/ICS/Intuitive P/A > Clear DTCs

(c) Recheck for DTCs.

Body Electrical > Advanced Parking Guidance/ICS/Intuitive P/A > Trouble Codes

Result

Proceed to

DTC C1AEC is output

A

No DTCs are output

B
B

USE SIMULATION METHOD TO CHECK

A

3.

CHECK HARNESS AND CONNECTOR (CLEARANCE WARNING ECU ASSEMBLY - FRONT CORNER ULTRASONIC SENSOR LH)

(a) Disconnect the J38 clearance warning ECU assembly connector.

(b) Disconnect the B7 front corner ultrasonic sensor LH connector.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

J38-4 (BOF) - B7-4 (BI)

Always

Below 1 Ω

J38-8 (SOF) - B7-5 (SI)

Always

Below 1 Ω

J38-6 (E5) - B7-6 (EI)

Always

Below 1 Ω

J38-4 (BOF) or B7-4 (BI) - Body ground

Always

10 kΩ or higher

J38-8 (SOF) or B7-5 (SI) - Body ground

Always

10 kΩ or higher

J38-6 (E5) or B7-6 (EI) - Body ground

Always

10 kΩ or higher
NG

REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

4.

CHECK HARNESS AND CONNECTOR (FRONT CORNER ULTRASONIC SENSOR LH - FRONT CENTER ULTRASONIC SENSOR LH)

(a) Disconnect the B8 front center ultrasonic sensor LH connector.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

B7-1 (BO) - B8-4 (BI)

Always

Below 1 Ω

B7-2 (SO) - B8-5 (SI)

Always

Below 1 Ω

B7-3 (EO) - B8-6 (EI)

Always

Below 1 Ω

B7-1 (BO) or B8-4 (BI) - Body ground

Always

10 kΩ or higher

B7-2 (SO) or B8-5 (SI) - Body ground

Always

10 kΩ or higher

B7-3 (EO) or B8-6 (EI) - Body ground

Always

10 kΩ or higher
NG

REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

5.

CHECK HARNESS AND CONNECTOR (FRONT CENTER ULTRASONIC SENSOR LH - FRONT CENTER ULTRASONIC SENSOR RH)

(a) Disconnect the B9 front center ultrasonic sensor RH connector.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

B8-1 (BO) - B9-4 (BI)

Always

Below 1 Ω

B8-2 (SO) - B9-5 (SI)

Always

Below 1 Ω

B8-3 (EO) - B9-6 (EI)

Always

Below 1 Ω

B8-1 (BO) or B9-4 (BI) - Body ground

Always

10 kΩ or higher

B8-2 (SO) or B9-5 (SI) - Body ground

Always

10 kΩ or higher

B8-3 (EO) or B9-6 (EI) - Body ground

Always

10 kΩ or higher
NG

REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

6.

CHECK HARNESS AND CONNECTOR (FRONT CENTER ULTRASONIC SENSOR RH - FRONT CORNER ULTRASONIC SENSOR RH)

(a) Disconnect the B10 front corner ultrasonic sensor RH connector.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

B9-1 (BO) - B10-4 (BI)

Always

Below 1 Ω

B9-2 (SO) - B10-5 (SI)

Always

Below 1 Ω

B9-3 (EO) - B10-6 (EI)

Always

Below 1 Ω

B9-1 (BO) or B10-4 (BI) - Body ground

Always

10 kΩ or higher

B9-2 (SO) or B10-5 (SI) - Body ground

Always

10 kΩ or higher

B9-3 (EO) or B10-6 (EI) - Body ground

Always

10 kΩ or higher
NG

REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

7.

INSPECT FRONT CORNER ULTRASONIC SENSOR LH

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

4 (BI) - 6 (EI)

Always

10 kΩ or higher

4 (BI) - 1 (BO)

Always

Below 1 Ω

5 (SI) - 2 (SO)

Always

Below 30 Ω

6 (EI) - 3 (EO)

Always

Below 1 Ω

*a

Component without harness connected

(Front Corner Ultrasonic Sensor LH)
NG

REPLACE FRONT CORNER ULTRASONIC SENSOR LH

OK

8.

INSPECT FRONT CENTER ULTRASONIC SENSOR LH

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

4 (BI) - 6 (EI)

Always

10 kΩ or higher

4 (BI) - 1 (BO)

Always

Below 1 Ω

5 (SI) - 2 (SO)

Always

Below 30 Ω

6 (EI) - 3 (EO)

Always

Below 1 Ω

*a

Component without harness connected

(Front Center Ultrasonic Sensor LH)
NG

REPLACE FRONT CENTER ULTRASONIC SENSOR LH

OK

9.

INSPECT FRONT CENTER ULTRASONIC SENSOR RH

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

4 (BI) - 6 (EI)

Always

10 kΩ or higher

4 (BI) - 1 (BO)

Always

Below 1 Ω

5 (SI) - 2 (SO)

Always

Below 30 Ω

6 (EI) - 3 (EO)

Always

Below 1 Ω

*a

Component without harness connected

(Front Center Ultrasonic Sensor RH)
NG

REPLACE FRONT CENTER ULTRASONIC SENSOR RH

OK

10.

INSPECT FRONT CORNER ULTRASONIC SENSOR RH

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

4 (BI) - 6 (EI)

Always

10 kΩ or higher

4 (BI) - 1

Always

Below 1 Ω

5 (SI) - 2

Always

Below 30 Ω

6 (EI) - 3

Always

Below 1 Ω

*a

Component without harness connected

(Front Corner Ultrasonic Sensor RH)
NG

REPLACE FRONT CORNER ULTRASONIC SENSOR RH

OK

11.

REPLACE FRONT CORNER ULTRASONIC SENSOR LH

Click here

NEXT

12.

CHECK DTC OUTPUT (C1AEC)

(a) Clear the DTCs.

Body Electrical > Advanced Parking Guidance/ICS/Intuitive P/A > Clear DTCs

(b) Check for DTCs.

Body Electrical > Advanced Parking Guidance/ICS/Intuitive P/A > Trouble Codes

Result

Proceed to

DTC C1AEC is output

A

No DTCs are output

B
B

END (FRONT LEFT SENSOR WAS DEFECTIVE)
A

13.

REPLACE FRONT CENTER ULTRASONIC SENSOR LH

Click here

NEXT

14.

CHECK DTC OUTPUT (C1AEC)

(a) Clear the DTCs.

Body Electrical > Advanced Parking Guidance/ICS/Intuitive P/A > Clear DTCs

(b) Check for DTCs.

Body Electrical > Advanced Parking Guidance/ICS/Intuitive P/A > Trouble Codes

Result

Proceed to

DTC C1AEC is output

A

No DTCs are output

B
B

END (FRONT LEFT CENTER SENSOR WAS DEFECTIVE)
A

15.

REPLACE FRONT CENTER ULTRASONIC SENSOR RH

Click here

NEXT

16.

CHECK DTC OUTPUT (C1AEC)

(a) Clear the DTCs.

Body Electrical > Advanced Parking Guidance/ICS/Intuitive P/A > Clear DTCs

(b) Check for DTCs.

Body Electrical > Advanced Parking Guidance/ICS/Intuitive P/A > Trouble Codes

Result

Proceed to

DTC C1AEC is output

A

No DTCs are output

B
B

END (FRONT RIGHT CENTER SENSOR WAS DEFECTIVE)
A

17.

REPLACE FRONT CORNER ULTRASONIC SENSOR RH

Click here

NEXT

18.

CHECK DTC OUTPUT (C1AEC)

(a) Clear the DTCs.

Body Electrical > Advanced Parking Guidance/ICS/Intuitive P/A > Clear DTCs

(b) Check for DTCs.

Body Electrical > Advanced Parking Guidance/ICS/Intuitive P/A > Trouble Codes

Result

Proceed to

DTC C1AEC is output

A

No DTCs are output

B
A

REPLACE CLEARANCE WARNING ECU ASSEMBLY

B

END (FRONT RIGHT SENSOR WAS DEFECTIVE)
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