DTC Troubleshooting: B2964 (I-B5), B2964 (93)

DTC B2964 or DTC screen I-B5 or DTC indicator 93  : Climate control unit lost communication with Front PANEL (climate control panel)

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
   B2964 Climate control unit lost communication with Front PANEL (climate control panel)

   Is DTC B2964 or Error on the DTC screen I-B5 (climate control panel without display) or 93 (climate control panel with display) indicated?

   YES 

   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. D9 (10 A)
   Location	Under-dash fuse/relay box

   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. D9 (10 A) fuse circuit.

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

   -1. Disconnect the following connector.

   Climate control panel 20P 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 20P connector: disconnected
   Test point 1	Climate control panel 20P connector (female terminals) No. 13:
   Test point 2	Climate control panel 20P connector (female terminals) No. 19:

   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 20P 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 OK. 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 20P connector: disconnected
   Test point 1	Climate control unit connector A (32P) No. 29
   Test point 2	Climate control panel 20P connector (female terminals) No. 18:

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

   Is there continuity?

   YES 

   The BUS-DATA wire is not open. Go to step 6.

   NO 

   Repair an open in the BUS-DATA wire.

6. Climate control panel check (substitution)

   -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
   B2964 Climate control unit lost communication with Front PANEL (climate control panel)

   Is DTC B2964 or Error on the DTC screen D-B5 (climate control panel without display) or 93 (climate control panel with display) 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 20P connector: disconnected
   Test point 1	Climate control panel 20P connector (female terminals) No. 19:
   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 G402.

   NO 

   Repair an open in the IG2 A/C wire.