DTC Troubleshooting: B1235 (B-A3), B1235 (42)
DTC B1235 or DTC screen B-A3 or DTC indicator 42: A problem in the air mix control motor circuit, linkage, door, or motor (driver's)
DTC Description
DTC
B1235 A problem in the air mix control motor circuit, linkage, door, or motor (driver's)
  

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
B1235 A problem in the air mix control motor circuit, linkage, door, or motor (driver's)
  

Is DTC B1235 or Error on the DTC screen B-A3 (climate control panel without display) or 42 (climate control panel with display) indicated?

     
YES
     
     
     
Go to step 2.
     
NO
     
     
     
Intermittent failure. Check for loose wires or poor connections on the air mix control motor circuit.?
2.
Open wire check (M-HOT-DR line):

Open wire check (M-HOT-DR line)
?1.
Turn the vehicle to the OFF (LOCK) mode.

?2.
Disconnect the following connectors.
Climate control unit connector B (24P)
Without dual zone control: Air mix control motor 5P connector
With dual zone control: Driver's air mix control motor 5P connector

?3.
Check for continuity between test points 1 and 2.
Without dual zone control
Test condition
Vehicle OFF (LOCK) mode
Climate control unit connector B (24P): disconnected
Air mix control motor 5P connector: disconnected
Test point 1
Climate control unit connector B (24P) No. 13
Test point 2
Air mix control motor 5P connector (female terminals) No. 5:

With dual zone control
Test condition
Vehicle OFF (LOCK) mode
Climate control unit connector B (24P): disconnected
Driver's air mix control motor 5P connector: disconnected
Test point 1
Climate control unit connector B (24P) No. 13
Test point 2
Driver's air mix control motor 5P connector (female terminals) No. 4:


Is there continuity?

     
YES
     
     
     
The M-HOT-DR wire is not open. Go to step 3.
     
NO
     
     
     
Repair an open in the M-HOT-DR wire.?
3.
Open wire check (M-COOL-DR line):

Open wire check (M-COOL-DR line)
?1.
Check for continuity between test points 1 and 2.
Without dual zone control
Test condition
Vehicle OFF (LOCK) mode
Climate control unit connector B (24P): disconnected
Air mix control motor 5P connector: disconnected
Test point 1
Climate control unit connector B (24P) No. 14
Test point 2
Air mix control motor 5P connector (female terminals) No. 4:

With dual zone control
Test condition
Vehicle OFF (LOCK) mode
Climate control unit connector B (24P): disconnected
Driver's air mix control motor 5P connector: disconnected
Test point 1
Climate control unit connector B (24P) No. 14
Test point 2
Driver's air mix control motor 5P connector (female terminals) No. 5:


Is there continuity?

     
YES
     
     
     
The M-COOL-DR wire is not open. Go to step 4.
     
NO
     
     
     
Repair an open in the M-COOL-DR wire.?
4.
Shorted wire check (M-HOT-DR line):

Shorted wire check (M-HOT-DR line)
?1.
Check for continuity between test points 1 and 2.
Without dual zone control
Test condition
Vehicle OFF (LOCK) mode
Climate control unit connector B (24P): disconnected
Air mix control motor 5P connector: disconnected
Test point 1
Climate control unit connector B (24P) No. 13
Test point 2
Body ground

With dual zone control
Test condition
Vehicle OFF (LOCK) mode
Climate control unit connector B (24P): disconnected
Driver's air mix control motor 5P connector: disconnected
Test point 1
Climate control unit connector B (24P) No. 13
Test point 2
Body ground

Is there continuity?

     
YES
     
     
     
Repair a short to ground in the M-HOT-DR wire.?
     
NO
     
     
     
The M-HOT-DR wire is OK. Go to step 5.
5.
Shorted wire check (M-COOL-DR line):

Shorted wire check (M-COOL-DR line)
?1.
Check for continuity between test points 1 and 2.
Without dual zone control
Test condition
Vehicle OFF (LOCK) mode
Climate control unit connector B (24P): disconnected
Air mix control motor 5P connector: disconnected
Test point 1
Climate control unit connector B (24P) No. 14
Test point 2
Body ground

With dual zone control
Test condition
Vehicle OFF (LOCK) mode
Climate control unit connector B (24P): disconnected
Driver's air mix control motor 5P connector: disconnected
Test point 1
Climate control unit connector B (24P) No. 14
Test point 2
Body ground

Is there continuity?

     
YES
     
     
     
Repair a short to ground in the M-COOL-DR wire.?
     
NO
     
     
     
The M-COOL-DR wire is OK. Go to step 6.
6.
Air mix control motor (without dual zone control) or driver's air mix control motor (with dual zone control) check:

Air mix control motor (without dual zone control) or driver's air mix control motor (with dual zone control) check
?1.
Test the air mix control motor (without dual zone control) or driver's air mix control motor (with dual zone control).

Is the air mix control motor (without dual zone control) or driver's air mix control motor (with dual zone control) OK?

     
YES
     
     
     
     
NO
     
     
     
Replace the air mix control motor, or repair the air mix control linkage or door.?
     
NO
     
     
     
Replace the driver's air mix control motor, or repair the driver's air mix control linkage or door.?