DTC Troubleshooting: B1240 (B-B3), B1240 (4b)

DTC B1240 or DTC screen B-B3 or DTC indicator 4b  : A problem in the mode control motor circuit, linkage, door, or motor

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
   B1240 A problem in the mode control motor circuit, linkage, door, or motor

   Is DTC B1240 or Error on the DTC screen B-B3 (climate control panel without display) or 4b (climate control panel with display) indicated?

   YES 

   Go to step 2.

   NO 

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

2. Open wire check (M-DEF line)

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

   -2. Disconnect the following connectors.

   Climate control unit connector B (24P)

   Mode control motor 5P connector

   -3. Check for continuity between test points 1 and 2.

   Test condition	Vehicle OFF (LOCK) mode
   	Climate control unit connector B (24P): disconnected
   	Mode control motor 5P connector: disconnected
   Test point 1	Climate control unit connector B (24P) No. 20
   Test point 2	Mode control motor 5P connector (female terminals) No. 5:

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

   Is there continuity?

   YES 

   The M-DEF wire is not open. Go to step 3.

   NO 

   Repair an open in the M-DEF wire.

3. Open wire check (M-VENT line)

   -1. Check for continuity between test points 1 and 2.

   Test condition	Vehicle OFF (LOCK) mode
   	Climate control unit connector B (24P): disconnected
   	Mode control motor 5P connector: disconnected
   Test point 1	Climate control unit connector B (24P) No. 19
   Test point 2	Mode control motor 5P connector (female terminals) No. 4:

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

   Is there continuity?

   YES 

   The M-VENT wire is not open. Go to step 4.

   NO 

   Repair an open in the M-VENT wire.

4. Shorted wire check (M-DEF line)

   -1. Check for continuity between test points 1 and 2.

   Test condition	Vehicle OFF (LOCK) mode
   	Climate control unit connector B (24P): disconnected
   	Mode control motor 5P connector: disconnected
   Test point 1	Climate control unit connector B (24P) No. 20
   Test point 2	Body ground

   Is there continuity?

   YES 

   Repair a short to ground in the M-DEF wire.

   NO 

   The M-DEF wire is OK. Go to step 5.

5. Shorted wire check (M-VENT line)

   -1. Check for continuity between test points 1 and 2.

   Test condition	Vehicle OFF (LOCK) mode
   	Climate control unit connector B (24P): disconnected
   	Mode control motor 5P connector: disconnected
   Test point 1	Climate control unit connector B (24P) No. 19
   Test point 2	Body ground

   Is there continuity?

   YES 

   Repair a short to ground in the M-VENT wire.

   NO 

   The M-VENT wire is OK. Go to step 6.

6. Mode control motor check

   -1. Test the mode control motor .

   Is the mode control motor OK?

   YES 

   Replace the climate control unit .

   NO 

   Replace the mode control motor , or repair the mode control linkage or door.