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)

DTCs (AC)

1. 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)

   -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:

   Courtesy of HONDA, U.S.A., INC.

   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:

   Courtesy of HONDA, U.S.A., INC.

   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)

   -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:

   Courtesy of HONDA, U.S.A., INC.

   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:

   Courtesy of HONDA, U.S.A., INC.

   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)

   -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)

   -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

   -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 

   Replace the climate control unit .

   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.