DTC Troubleshooting: B1237 (B-A5)
DTC B1237 or DTC screen B-A5: A Short in the Passenger's Air Mix Control Motor Circuit
NOTE: If other short circuit DTCs are indicated at the same time, there may be an open or short to body ground in the power (5 V) circuit.

DTC Description
DTC
B1237 A short in the passenger’s air mix control motor circuit
  

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
B1237 A short in the passenger’s air mix control motor circuit
  

Is DTC B1237 or Error on the DTC screen B-A5 indicated?

     
YES
     
     
     
Go to step 2.
     
NO
     
     
     
Intermittent failure. Check for loose wires or poor connections on the passenger's air mix control motor circuit.?
2.
Determine possible failure area (S5V-H line, others):

Determine possible failure area (S5V-H line, others)
?1.
Turn the vehicle to the OFF (LOCK) mode.

?2.
Disconnect the following connector.
Passenger's air mix control motor 5P connector

?3.
Turn the vehicle to the ON mode.

?4.
Measure the voltage between test points 1 and 2.
Test condition
Vehicle ON mode
Passenger's air mix control motor 5P connector: disconnected
Test point 1
Passenger's air mix control motor 5P connector No. 5
Test point 2
Body ground


Is there about 5 V?

     
YES
     
     
     
The S5V-H wire is OK. Go to step 3.
     
NO
     
     
     
Go to step 4.
3.
Determine possible failure area (passenger's air mix control motor, others):

Determine possible failure area (passenger's air mix control motor, others)
?1.
Measure the voltage between test points 1 and 2.
Test condition
Vehicle ON mode
Passenger's air mix control motor 5P connector: disconnected
Test point 1
Passenger's air mix control motor 5P connector No. 4
Test point 2
Body ground


Is there about 5 V?

     
YES
     
     
     
     
NO
     
     
     
Go to step 6.
4.
Open wire check (S5V-H line):

Open wire check (S5V-H line)
?1.
Measure the voltage between test points 1 and 2.
Test condition
Vehicle ON mode
Passenger's air mix control motor 5P connector: disconnected
Test point 1
Climate control unit connector B (24P) No. 1
Test point 2
Body ground

Is there about 5 V?

     
YES
     
     
     
Repair an open in the S5V-H wire.?
     
NO
     
     
     
The S5V-H wire is not open. Go to step 5.
5.
Shorted wire check (S5V-H line):

Shorted wire check (S5V-H line)
?1.
Turn the vehicle to the OFF (LOCK) mode.

?2.
Disconnect the following connector.
Climate control unit connector B (24P)

?3.
Check for continuity between test points 1 and 2.
Test condition
Vehicle OFF (LOCK) mode
Climate control unit connector B (24P): disconnected
Passenger's air mix control motor 5P connector: disconnected
Test point 1
Climate control unit connector B (24P) No. 1
Test point 2
Body ground

Is there continuity?

     
YES
     
     
     
Repair a short to ground in the S5V-H wire.?
     
NO
     
     
     
6.
Shorted wire check (AMD-P-AS line):

Shorted wire check (AMD-P-AS line)
?1.
Turn the vehicle to the OFF (LOCK) mode.

?2.
Disconnect the following connector.
Climate control unit connector B (24P)

?3.
Check for continuity between test points 1 and 2.
Test condition
Vehicle OFF (LOCK) mode
Climate control unit connector B (24P): disconnected
Passenger's air mix control motor 5P connector: disconnected
Test point 1
Climate control unit connector B (24P) No. 3
Test point 2
Body ground

Is there continuity?

     
YES
     
     
     
Repair a short to ground in the AMD-P-AS wire.?
     
NO