DTC B120A (8A)

DTC B120A or DTC indicator 8A  : Climate Control Unit LIN Communication Bus Line Error

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
   B120A Climate Control Unit LIN Communication Bus Line Error

   Is DTC B120A or 8A indicated?

   YES 

   The failure is duplicated. Go to step 2.

   NO 

   Intermittent failure. Check for loose wires or poor connections on the climate control panel circuit.

2. Fuse check

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

   -2. Check the following fuse.

   Fuse

   No. B14

   Is the fuse OK?

   YES 

   Go to step 3.

   NO 

   Replace the fuse, and recheck. If the fuse blows again, repair a short in the No. B14 fuse circuit.

3. Determine possible failure area (BUS-DATA line, others)

   -1. Disconnect the following connector.

   Climate control panel 12P connector

   -2. Turn the vehicle to the ON mode.

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

   Test condition	Vehicle ON mode
   	Climate control panel 12P connector: disconnected
   Test point 1	Climate control panel 12P connector (female terminals) No. 1:
   Test point 2	Climate control panel 12P connector (female terminals) No. 4:

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

   Is there battery voltage?

   YES 

   Go to step 4.

   NO 

   Go to step 7.

4. Shorted wire check (BUS-DATA line)

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

   -2. Disconnect the following connector.

   Climate control unit connector A (32P)

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

   Test condition	Vehicle OFF (LOCK) mode
   	Climate control unit connector A (32P): disconnected
   	Climate control panel 12P connector: disconnected
   Test point 1	Climate control unit connector A (32P) No. 29
   Test point 2	Body ground

   Is there continuity?

   YES 

   Repair a short to ground in the BUS-DATA wire.

   NO 

   The BUS-DATA wire is not shorted. Go to step 5.

5. Open wire check (BUS-DATA line)

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

   Test condition	Vehicle OFF (LOCK) mode
   	Climate control unit connector A (32P): disconnected
   	Climate control panel 12P connector: disconnected
   Test point 1	Climate control unit connector A (32P) No. 29
   Test point 2	Climate control panel 12P connector (female terminals) No. 9:

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

   Is there continuity?

   YES 

   The BUS-DATA wire is OK. Go to step 6.

   NO 

   Repair an open in the BUS-DATA wire.

6. Climate control panel check

   -1. Reconnect the following connector.

   Climate control unit connector A (32P)

   -2. Substitute a known-good climate control panel .

   -3. Clear the DTCs with the HDS.

   -4. Turn the vehicle to the OFF (LOCK) mode and then the ON mode.

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

   -6. Check for DTCs.

   DTC Description	DTC
   B120A Climate Control Unit LIN Communication Bus Line Error

   Is DTC B120A or 8A indicated?

   YES 

   Replace the climate control unit .

   NO 

   Replace the original climate control panel .

7. Open wire check (IG2 A/C line)

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

   Test condition	Vehicle ON mode
   	Climate control panel 12P connector: disconnected
   Test point 1	Climate control panel 12P connector (female terminals) No. 1:
   Test point 2	Body ground

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

   Is there battery voltage?

   YES 

   Check for an open in the GND wire. If the wire is OK, check for poor ground at G504.

   NO 

   Repair an open in the IG2 A/C wire.