CAN COMMUNICATION SYSTEM(for RHD), Diagnostic DTC:U023A

DTC Code	DTC Name
U023A	Lost Communication with Front Camera Module

DESCRIPTION

DTC No.	Detection Item	DTC Detection Condition	Trouble Area	DTC Output from
U023A	Lost Communication with Front Camera Module	There is no communication from the lane departure warning camera.	Power source circuit of lane departure warning camera Lane departure warning camera ground circuit Lane departure warning camera CAN branch wire or connector Lane departure warning camera Engine stop and start ECU	Network gateway ECU

For vehicles with a lane departure alert system.

WIRING DIAGRAM

Figure 1. w/o Stop and Start System


*1	No. 3 CAN Junction Connector
*2	ECU-IG NO.1
*3	from IG1 NO.1 Relay
*4	Lane Departure Warning Camera

Figure 2. w/ Stop and Start System


*1	No. 3 CAN Junction Connector
*2	Engine Stop and Start ECU
*3	Lane Departure Warning Camera

CAUTION / NOTICE / HINT

Note

Before measuring the resistance of the CAN bus, turn the engine switch off and leave the vehicle for 1 minute or more without operating the key or any switches, or opening or closing the doors. After that, disconnect the cable from the negative (-) battery terminal and leave the vehicle for 1 minute or more before measuring the resistance.
After turning the engine switch off, waiting time may be required before disconnecting the cable from the negative (-) battery terminal. Therefore, make sure to read the disconnecting the cable from the negative (-) battery terminal notices before proceeding with work.

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Because the order of diagnosis is important to allow correct diagnosis, make sure to begin troubleshooting using How to Proceed with Troubleshooting when CAN communication system related DTCs are output.

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After performing repairs, perform the DTC check procedure and confirm that the DTCs are not output again.
DTC check procedure: Turn the engine switch on (IG) and wait at least 52 seconds, and then drive the vehicle at a speed of 1 km/h (1 mph) or more for 7 seconds or more.
After the repair, perform the CAN bus check and check that all the ECUs and sensors connected to the CAN communication system are displayed.

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Inspect the fuses for circuits related to this system before performing the following procedure.
When replacing the lane departure warning camera, make sure to replace it with a new one.

Tech Tips

Operating the engine switch, any other switches or a door triggers related ECU and sensor communication on the CAN. This communication will cause the resistance value to change.
Even after DTCs are cleared, if a DTC is stored again after driving the vehicle for a while, the malfunction may be occurring due to vibration of the vehicle. In such a case, wiggling the ECUs or wire harness while performing the inspection below may help determine the cause of the malfunction.

PROCEDURE

RECONFIRM DTC OUTPUT

Check for DTCs.

Body Electrical > Gateway > Trouble Codes

Tech Tips

If DTC U1002 is output from the gateway of the network gateway ECU, this indicates a sub bus 2 malfunction. Troubleshoot for DTC U1002 and check for malfunctions in sub bus 2.

Result

Result	Proceed to
U1002 is not output from network gateway ECU	A
U1002 is output from network gateway ECU	B

GO TO DIAGNOSIS PROCEDURE INDICATED BY OUTPUT DTC Click here

CHECK FOR OPEN IN CAN BUS WIRE (LANE DEPARTURE WARNING CAMERA BRANCH WIRE)

*a
Front view of wire harness connector

(to Lane Departure Warning Camera)

Disconnect the cable from the negative (-) battery terminal.
Disconnect the lane departure warning camera connector.

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

Standard Resistance

Tester Connection	Condition	Specified Condition
T10-6 (CA1P) - T10-12 (CA1N)	Cable disconnected from negative (-) battery terminal	54 to 69 Ω

Result

Proceed to
OK
NG

REPAIR OR REPLACE CAN BRANCH WIRE OR CONNECTOR (LANE DEPARTURE WARNING CAMERA)

CHECK HARNESS AND CONNECTOR (LANE DEPARTURE WARNING CAMERA - BODY GROUND)

*a
Front view of wire harness connector

(to Lane Departure Warning Camera)

Reconnect the cable to the negative (-) battery terminal.

Note

When disconnecting the cable, some systems need to be initialized after the cable is reconnected.

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

Standard Resistance

Tester Connection	Condition	Specified Condition
T10-11 (GND) - Body ground	Always	Below 1 Ω

Result

Proceed to
OK
NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

CHECK HARNESS AND CONNECTOR (LANE DEPARTURE WARNING CAMERA - BATTERY)

*a	Front view of wire harness connector (to Lane Departure Warning Camera)

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

Standard Voltage

w/o Stop and Start System
Tester Connection	Switch Condition	Specified Condition
T10-7 (IGB) - Body ground	Engine switch on (IG)	11 to 14 V

w/ Stop and Start System
Tester Connection	Switch Condition	Specified Condition
T10-7 (IGB) - Body ground	Engine switch on (IG)	10.5 to 16 V

Result

Result	Proceed to
OK	A
NG (w/o Stop and Start System)	B
NG (w/ Stop and Start System)	C

REPLACE LANE DEPARTURE WARNING CAMERA Click here

REPAIR OR REPLACE HARNESS OR CONNECTOR

CHECK HARNESS AND CONNECTOR (LANE DEPARTURE WARNING CAMERA - ENGINE STOP AND START ECU)

Disconnect the I57 engine stop and start ECU connector.

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

Standard Resistance

Tester Connection	Condition	Specified Condition
T10-7 (IGB) - I57-12 (IGO1)	Always	Below 1 Ω
T10-7 (IGB) or I57-12 (IGO1) - Body ground	Always	10 kΩ or higher

Result

Proceed to
OK
NG

GO TO STOP AND START SYSTEM Click here

REPAIR OR REPLACE HARNESS OR CONNECTOR