DTC Troubleshooting: U0164, U1299
DTC U0164: Door Multiplex Control Unit Lost Communication With Climate Control Unit
DTC U1299: Door Multiplex Control Unit Lost Communication With Climate Control Unit
DTC Description
DTC
U0164 Door multiplex control unit lost communication with climate control unit
  
U1299 Door multiplex control unit lost communication with climate control unit
  

1.
Problem verification:

Problem verification
?1.
Clear the DTCs with the HDS.


?2.
Turn the ignition switch to LOCK (0) and then back to ON (II), or press the engine start/stop button to select the OFF mode and then the ON mode.

?3.
Wait for at least 6 seconds.

?4.
Check for DTCs with the HDS.
DTC Description
DTC
U0164 Door multiplex control unit lost communication with climate control unit
  
U1299 Door multiplex control unit lost communication with climate control unit
  

Is DTC U0164 or U1299 indicated?

     
YES
     
     
     
Go to step 2.
     
NO
     
     
     
Intermittent failure, the system is OK at this time. Check for loose or poor connections.?
2.
Determine possible failure area (climate control unit power and ground, B CAN line):

Determine possible failure area (climate control unit power and ground, B CAN line)
?1.
Select B-CAN CONTROL UNITS INFORMATION from the BODY ELECTRICAL SYSTEM SELECT menu, and then select CHECK CONNECTED CONTROL UNITS.

?2.
Check the DETECT/NOT AVAILABLE information of the CLIMATE CONTROL UNIT

Is DETECT indicated?

     
YES
     
     
     
Go to step 7.
     
NO
     
     
     
Go to step 3.
3.
Fuse check:

Fuse check
?1.
Check the following fuse.
Fuse
No. B1 (7.5 A)
Location
Under-dash fuse/relay box

Is the fuse OK?

     
YES
     
     
     
Go to step 4.
     
NO
     
     
     
Replace the fuse. If the fuse blows again, repair a short to ground in the No. B1 (7.5 A) fuse circuit.?
4.
Open wire check (IG2 A/C line):

Open wire check (IG2 A/C line)
?1.
Turn the ignition switch to LOCK (0), or press the engine start/stop button to select the OFF mode.

?2.
Disconnect the following connector.

?3.
Turn the ignition switch to ON (II), or press the engine start/stop button to select the ON mode.

?4.
Measure the voltage between test points 1 and 2.
Test condition
IG ON (II) or ON mode
Climate control unit 32P connector: disconnected
Test circuit
IG2 A/C
Test point 1
Climate control unit 32P connector No. 6 (LT GRN)
Test point 2
Body ground


Is there battery voltage?

     
YES
     
     
     
The IG2 A/C wire is OK. Go to step 5.
     
NO
     
     
     
Repair an open or high resistance in the wire.?
5.
Open wire check (GND line):

Open wire check (GND line)
?1.
Turn the ignition switch to LOCK (0), or press the engine start/stop button to select the OFF mode.

?2.
Check for continuity between test points 1 and 2.
Test condition
IG LOCK (0) or OFF mode
Climate control unit 32P connector: disconnected
Test circuit
GND
Test point 1
Climate control unit 32P connector No. 21 (BRN)
Test point 2
Body ground


Is there continuity?

     
YES
     
     
     
The GND wire is OK. Go to step 6.
     
NO
     
     
     
Repair an open or high resistance in the ground wire or poor ground (G506).?
6.
Open wire check (B-CAN lines):

Open wire check (B-CAN lines)
?1.
Disconnect the following connector.

?2.
Check for continuity between test points 1 and 2.
Test condition
IG LOCK (0) or OFF mode
Climate control unit 32P connector: disconnected
Power window master switch 37P connector: disconnected
Test circuit
B-CAN_H
Test point 1
Power window master switch 37P connector No. 28 (PNK)
Test point 2
Climate control unit 32P connector No. 32 (PNK)


Is there continuity?

     
YES
     
     
     
An open or poor connection in the B-CAN_L wire between the power window master switch and the climate control unit.?
     
NO
     
     
     
An open or poor connection in the B-CAN_H wire between the power window master switch and the climate control unit.?
7.
Open wire check (B-CAN lines):

Open wire check (B-CAN lines)
?1.
Turn the ignition switch to LOCK (0), or press the engine start/stop button to select the OFF mode.

?2.
Disconnect the following connectors.

?3.
Check for continuity between test points 1 and 2.
Test condition
IG LOCK (0) or OFF mode
Power window master switch 37P connector: disconnected
Climate control unit 32P connector: disconnected
Test circuit
B-CAN_H
Test point 1
Power window master switch 37P connector No. 28 (PNK)
Test point 2
Climate control unit 32P connector No. 32 (PNK)


Is there continuity?

     
YES
     
     
     
An open or poor connection in the B-CAN_L wire between the power window master switch and the climate control unit.?
     
NO
     
     
     
An open or poor connection in the B-CAN_H wire between the power window master switch and the climate control unit.?