DTC B1235 (B-A3), B1235 (42)

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

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

   YES 

   The failure is duplicated. Go to step 2.

   NO: Without dual zone climate control

   Intermittent failure. Check for loose wires or poor connections on the air mix control motor circuit.

   NO: With dual zone climate control

   Intermittent failure. Check for loose wires or poor connections on the driver's 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)

   Air mix control motor 5P connector (without dual zone climate control)

   Driver's air mix control motor 5P connector (with dual zone climate control)

   -3. Measure the resistance between test points 1 and 2.

   Without dual zone climate 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 climate 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 1.0 Ω or less?

   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. Measure the resistance between test points 1 and 2.

   Without dual zone climate 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 climate 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 1.0 Ω or less?

   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. Measure the resistance between test points 1 and 2.

   Test condition	Vehicle OFF (LOCK) mode
   	Climate control unit connector B (24P): disconnected
   	Air mix control motor 5P connector (without dual zone climate control): disconnected
   	Driver's air mix control motor 5P connector (with dual zone climate control): disconnected
   Test point 1	Climate control unit connector B (24P) No. 13
   Test point 2	Body ground

   Is there 1 MΩ or more?

   YES 

   The M-HOT-DR wire is OK. Go to step 5.

   NO 

   Repair a short to ground in the M-HOT-DR wire.

5. Shorted wire check (M-COOL-DR line)

   -1. Measure the resistance between test points 1 and 2.

   Test condition	Vehicle OFF (LOCK) mode
   	Climate control unit connector B (24P): disconnected
   	Air mix control motor 5P connector (without dual zone climate control): disconnected
   	Driver's air mix control motor 5P connector (with dual zone climate control) : disconnected
   Test point 1	Climate control unit connector B (24P) No. 14
   Test point 2	Body ground

   Is there 1 MΩ or more?

   YES: Without dual zone climate control

   The M-COOL-DR wire is OK. Go to step 6.

   YES: With dual zone climate control

   The M-COOL-DR wire is OK. Go to step 7.

   NO 

   Repair a short to ground in the M-COOL-DR wire.

6. Air mix control motor check

   -1. Test the air mix control motor .

   Is the air mix control motor OK?

   YES 

   Replace the climate control unit .

   NO 

   Replace the air mix control motor , or repair the air mix control linkage or door.

7. Driver's air mix control motor check

   -1. Test the driver's air mix control motor .

   Is the driver's air mix control motor OK?

   YES 

   Replace the climate control unit .

   NO 

   Replace the driver's air mix control motor , or repair the driver's air mix control linkage or door.