DTC Troubleshooting: B2964 (D-B5), B2964 (93)
DTC B2964, DTC screen D-B5, or DTC indicator 93: Climate Control Unit Lost Communication with Front Panel (Climate Control Panel)
DTC Description
DTC
B2964 Climate control unit lost communication with front panel (climate control panel)
  

1.
Problem verification:

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, Error on the DTC screen D-B5 (climate control panel without display), or DTC indicator 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:

Fuse check
?1.
Turn the vehicle to the OFF (LOCK) mode.

?2.
Check the following fuse.
Fuse
No. B9

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. B9 fuse circuit.?
3.
Determine possible failure area (BUS-DATA line, others):

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 No. 1
Test point 2
Climate control panel 12P connector No. 4


Is there battery voltage?

     
YES
     
     
     
Go to step 4.
     
NO
     
     
     
Go to step 7.
4.
Shorted wire check (BUS-DATA line):

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 body 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):

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 No. 9


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:

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
B2964 Climate control unit lost communication with front panel (climate control panel)
  

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

     
YES
     
     
     
     
NO
     
     
     
7.
Open wire check (IG2 A/C (L15B7/K20C2 engine) or IG2 OPTION (L15BA/K20C1/L15BY engine) line):

Open wire check (IG2 A/C (L15B7/K20C2 engine) or IG2 OPTION (L15BA/K20C1/L15BY engine) 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 No. 1
Test point 2
Body ground


Is there battery voltage?

     
YES
     
     
     
Check for an open in the GND wire between the climate control panel and body ground. If the wire is OK, check for poor ground at G503.?
     
NO: L15B7/K20C2 engine
     
     
     
Repair an open in the IG2 A/C wire.?
     
NO: L15BA/K20C1/lL15BY engine
     
     
     
Repair an open in the IG2 OPTION wire.?