DTC Troubleshooting: B1226 (04)
DTC B1226 or DTC indicator 04: A Short in the In-Car Temperature Sensor Circuit
DTC Description
DTC
B1226 A short in the in-car temperature sensor circuit
  

1.
Problem verification:

Problem verification
?1.
Clear the DTC 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.
Do the Self-Diagnostic Function with the HDS or the climate control unit.

?4.
Check for DTCs.
DTC Description
DTC
B1226 A short in the in-car temperature sensor circuit
  

Is DTC B1226 or 04 indicated?

     
YES
     
     
     
Go to step 2.
     
NO
     
     
     
Intermittent failure. Check for loose wires or poor connections on the in-car temperature circuit.?
2.
Shorted wire check (TR line):

Shorted wire check (TR 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 connectors.

?3.
Check for continuity between test points 1 and 2.
Test condition
IG LOCK (0) or OFF mode
Climate control unit 32P connector: disconnected
In-car temperature sensor 2P connector: disconnected
Test circuit
TR
Test point 1
Climate control unit 32P connector No. 23 (LT BLU)
Test point 2
Body ground


Is there continuity?

     
YES
     
     
     
Repair a short to body ground in the wire between the climate control unit and the in-car temperature sensor.?
     
NO
     
     
     
The TR wire is not shorted. Go to step 3.
3.
Shorted wire check (TR line to SENSOR COM line):

Shorted wire check (TR line to SENSOR COM line)
?1.
Check for continuity between test points 1 and 2.
Test condition
IG LOCK (0) or OFF mode
Climate control unit 32P connector: disconnected
In-car temperature sensor 2P connector: disconnected
Test circuit
TR, SENSOR COM
Test point 1
Climate control unit 32P connector No. 23 (LT BLU)
Test point 2
Climate control unit 32P connector No. 22 (BLU)


Is there continuity?

     
YES
     
     
     
Repair a short in the wires between the climate control unit and the in-car temperature sensor.?
     
NO
     
     
     
The TR wire and SENSOR COM wire are OK. Go to step 4.
4.
In-car temperature sensor check:

In-car temperature sensor check
?1.
Test the in-car temperature sensor.

Is the in-car temperature sensor OK?

     
YES
     
     
     
     
NO