DTC Troubleshooting: B123F (A-A3), B123F (17)

1.

Problem verification:

Problem verification

?1.	Clear the DTCs with the HDS.

?2.	Turn the vehicle to the OFF (LOCK) mode and then the ON mode.

?3.	Do the Self-Diagnostic Function with the HDS or the climate control unit.

?4.

Check for DTCs.

DTC Description	DTC
B123F Automatic lighting control unit/sunlight sensor error

Is DTC B123F or Error on the DTC screen A-A3 (climate control panel without display) or 17 (climate control panel with display) indicated?


	YES

Go to step 2.


	NO

Intermittent failure, the system is OK at this time.?

2.

Equipment check 1:

Equipment check 1

?1.	Turn the vehicle to the OFF (LOCK) mode.

?2.	Confirm the vehicle have an automatic lighting system.

Does the combination light switch have an AUTO position?


	YES

Go to step 3.


	NO

Go to step 4.

3.

Equipment check 2:

Equipment check 2

?1.	Confirm the vehicle have an automatic wiper system.

Does the wiper/washer switch have an AUTO position?


	YES

Go to step 4.


	NO

Go to step 9.

4.

Open wire check (TSUN line):

Open wire check (TSUN line)

?1.

Disconnect the following connectors.

Climate control unit connector A (32P)

Sunlight sensor 2P connector

?2.

Check for continuity between test points 1 and 2.

Test condition	Vehicle OFF (LOCK) mode
	Climate control unit connector A (32P): disconnected
	Sunlight sensor 2P connector: disconnected
Test point 1	Climate control unit connector A (32P) No. 10
Test point 2	Sunlight sensor 2P connector (female terminals) No. 2:

Is there continuity?


	YES

The TSUN wire is not open. Go to step 5.


	NO

Repair an open in the TSUN wire.?

5.

Open wire check (SENSOR COM line):

Open wire check (SENSOR COM line)

?1.

Check for continuity between test points 1 and 2.

Test condition	Vehicle OFF (LOCK) mode
	Climate control unit connector A (32P): disconnected
	Sunlight sensor 2P connector: disconnected
Test point 1	Climate control unit connector A (32P) No. 12
Test point 2	Sunlight sensor 2P connector (female terminals) No. 1:

Is there continuity?


	YES

The SENSOR COM wire is OK. Go to step 6.


	NO

Repair an open in the SENSOR COM wire.?

6.

Shorted wire check (TSUN line):

Shorted wire check (TSUN line)

?1.

Check for continuity between test points 1 and 2.

Test condition	Vehicle OFF (LOCK) mode
	Climate control unit connector A (32P): disconnected
	Sunlight sensor 2P connector: disconnected
Test point 1	Climate control unit connector A (32P) No. 10
Test point 2	Body ground

Is there continuity?


	YES

Repair a short to ground in the TSUN wire.?


	NO

The TSUN wire is not shorted. Go to step 7.

7.

Shorted wire check (TSUN line to SENSOR COM line):

Shorted wire check (TSUN line to SENSOR COM line)

?1.

Check for continuity between test points 1 and 2.

Test condition	Vehicle OFF (LOCK) mode
	Climate control unit connector A (32P): disconnected
	Sunlight sensor 2P connector: disconnected
Test point 1	Climate control unit connector A (32P) No. 10
Test point 2	Climate control unit connector A (32P) No. 12

Is there continuity?


	YES

Repair a short in the TSUN wire to SENSOR COM wire.?


	NO

The TSUN wire and SENSOR COM wire are OK. Go to step 8.

8.

Sunlight sensor check:

Sunlight sensor check

?1.

Reconnect the following connectors.

Climate control unit connector A (32P)

Sunlight sensor 2P connector

?2.	Test the sunlight sensor.

Is the sunlight sensor OK?


	YES

Replace the climate control unit.?


	NO

Replace the sunlight sensor.?

9.

Fuse check:

Fuse check

NOTE: Check for DTCs. If a DTC U1280 or Error on the DTC screen I-A1 (climate control panel without display) or 80 (climate control panel with display) indicated, troubleshoot the DTC first.

?1.

Check the following fuse.

Fuse	No. A18 (10 A)
Location	Under-hood fuse/relay box

Is the fuse OK?


	YES

Go to step 10.


	NO

Replace the fuse, and recheck. If the fuse blows again, repair a short in the No. A18 (10 A) fuse circuit.?

10.

Determine possible failure area (B-CAN lines, others):

Determine possible failure area (B-CAN lines, others)

?1.

Disconnect the following connector.

Automatic lighting control unit-sensor 5P connector

?2.

Measure the voltage between test points 1 and 2.

Test condition	Vehicle OFF (LOCK) mode
Test condition	Automatic lighting control unit-sensor 5P connector: disconnected
Test point 1	Automatic lighting control unit-sensor 5P connector No. 3
Test point 2	Automatic lighting control unit-sensor 5P connector No. 4

Is there battery voltage?


	YES

Go to step 11.


	NO

Go to step 14.

11.

Open wire check (B-CAN_H line):

Open wire check (B-CAN_H line)

?1.

Disconnect the following connector.

Climate control unit connector A (32P)

?2.

Check for continuity between test points 1 and 2.

Test condition	Vehicle OFF (LOCK) mode
	Automatic lighting control unit-sensor 5P connector: disconnected
	Climate control unit connector A (32P): disconnected
Test point 1	Automatic lighting control unit-sensor 5P connector No. 1
Test point 2	Climate control unit connector A (32P) No. 25

Is there continuity?


	YES

The B-CAN_H wire is OK. Go to step 12.


	NO

Repair an open in the B-CAN_H wire.?

12.

Open wire check (B-CAN_L line):

Open wire check (B-CAN_L line)

?1.

Check for continuity between test points 1 and 2.

Test condition	Vehicle OFF (LOCK) mode
	Automatic lighting control unit-sensor 5P connector: disconnected
	Climate control unit connector A (32P): disconnected
Test point 1	Automatic lighting control unit-sensor 5P connector No. 2
Test point 2	Climate control unit connector A (32P) No. 8

Is there continuity?


	YES

The B-CAN_L wire is OK. Go to step 13.


	NO

Repair an open in the B-CAN_L wire.?

13.

DTC check:

DTC check

?1.

Reconnect the following connectors.

Automatic lighting control unit-sensor 5P connector

Climate control unit connector A (32P)

?2.	Clear the DTC with the HDS.

?3.	Turn the vehicle to the OFF (LOCK) mode then the ON mode.

?4.	Wait for at least 8 seconds.

?5.	Do the Self-Diagnostic Function with the climate control unit.

?6.

Check for DTCs.

DTC Description	DTC
B123F Automatic lighting control unit/sunlight sensor error
U128D Climate Control Unit Lost communication with gauge control module

Is DTC B123F or Error on the DTC screen A-A3 (climate control panel without display) or 17 (climate control panel with display) and DTC U128D or Error on the DTC screen I-A2 (climate control panel without display) or 83 (climate control panel with display) indicated?


	YES

Replace the climate control unit.?


	NO

Replace the automatic lighting control unit-sensor.?

14.

Open wire check (+B BACK UP line):

Open wire check (+B BACK UP line)

?1.

Measure the voltage between test points 1 and 2.

Test condition	Vehicle OFF (LOCK) mode
Test condition	Automatic lighting control unit-sensor 5P connector: disconnected
Test point 1	Automatic lighting control unit-sensor 5P connector No. 4
Test point 2	Body ground

Is there battery voltage?


	YES

Check for an open in the GND wire. If the wire is OK, check for poor ground at G402.?


	NO

Repair an open in the +B BACK UP wire.?