DTC Troubleshooting: B1275, B1276, B1277, B1278
DTC B1275 : Headlight OFF position circuit malfunction DTC B1276 : Headlight switch parking (small) position circuit malfunction DTC B1277 : Head light AUTO position circuit malfunction DTC B1278 : Headlight ON position circuit malfunction 
 
DTC Description
 
DTC
   
B1275 Headlight OFF position circuit malfunction
 
   
B1276 Headlight switch parking (small) position circuit malfunction
 
   
B1277 Head light AUTO position circuit malfunction
 
   
B1278 Headlight ON position circuit malfunction
 
    
  
  
 DTC (MICU) 
1.
 
Problem verification:
Problem verification
?1.
 
Turn the vehicle to the ON mode.
   
?2.
 
Check the parameter(s) below with the HDS.
When the combination light switch is turned OFF
 
Signal
 
Threshold
 
Current conditions
  
Values
 
Unit
 
Values
 
Unit
   
Headlight Switch (OFF)
 
ON
 
  
     
Headlight Switch (PARKING)
 
OFF
 
  
     
Headlight Switch (AUTO)
 
OFF
 
  
     
Headlight Switch (HEADLIGHT)
 
OFF
 
  
      
  
  
 
When the combination light switch is turned to POSITION (PARKING)
 
Signal
 
Threshold
 
Current conditions
  
Values
 
Unit
 
Values
 
Unit
   
Headlight Switch (OFF)
 
OFF
 
  
     
Headlight Switch (PARKING)
 
ON
 
  
     
Headlight Switch (AUTO)
 
OFF
 
  
     
Headlight Switch (HEADLIGHT)
 
OFF
 
  
      
  
  
 
When the combination light switch is turned AUTO
 
Signal
 
Threshold
 
Current conditions
  
Values
 
Unit
 
Values
 
Unit
   
Headlight Switch (OFF)
 
OFF
 
  
     
Headlight Switch (PARKING)
 
OFF
 
  
     
Headlight Switch (AUTO)
 
ON
 
  
     
Headlight Switch (HEADLIGHT)
 
OFF
 
  
      
  
  
 
When the combination light switch is turned ON (HEADLIGHT)
 
Signal
 
Threshold
 
Current conditions
  
Values
 
Unit
 
Values
 
Unit
   
Headlight Switch (OFF)
 
OFF
 
  
     
Headlight Switch (PARKING)
 
ON
 
  
     
Headlight Switch (AUTO)
 
OFF
 
  
     
Headlight Switch (HEADLIGHT)
 
ON
 
  
      
  
  
    
   
Are all data list values correct?
 
Intermittent failure, the system is OK at this time. Check for loose or poor connections.?
   
 
   
 
2.
 
Exterior lights system check:
Exterior lights system check
?1.
 
Check the parameter(s) below with the HDS.
 
Signal
 
Current conditions
  
Values
 
Unit
   
Headlight Switch (OFF)
 
     
Headlight Switch (PARKING)
 
     
Headlight Switch (AUTO)
 
     
Headlight Switch (HEADLIGHT)
 
      
  
  
    
   
Is data list value OFF, not ON?
 
3.
 
Determine possible failure area (combination light switch, others):
Determine possible failure area (combination light switch, others)
?1.
 
Turn the vehicle to the OFF (LOCK) mode.
   
?2.
 
Disconnect the following connector.
 
Combination light switch 12P connector
   
  
  
    
?3.
 
Turn the vehicle to the ON mode.
   
?4.
 
Check the parameter(s) below with the HDS.
 
Signal
 
Current conditions
  
Values
 
Unit
   
Headlight Switch (OFF)
 
     
Headlight Switch (PARKING)
 
     
Headlight Switch (AUTO)
 
     
Headlight Switch (HEADLIGHT)
 
      
  
  
    
   
Has the data list value changed from ON to OFF?
 
4.
 
Shorted wire check (H/L OFF SW, H/L ON SW, PARKING LT SW lines):
Shorted wire check (H/L OFF SW, H/L ON SW, PARKING LT SW lines)
?1.
 
Turn the vehicle to the OFF (LOCK) mode.
   
?2.
 
Disconnect the following connector.
 
Under-dash fuse/relay box connector B (20P)
   
  
  
    
?3.
 
Check for continuity between test points 1 and 2 individually.
 
Test condition
 
Vehicle OFF (LOCK) mode
  
Test point 1
 
  
Test point 2
 
Body ground
   
  
  
 
 
Test point 1
 
  
Test point 2
 
Body ground
   
  
  
 
 
Test point 1
 
  
Test point 2
 
Body ground
   
  
  
    
   
Is there continuity?
 
Repair a short to ground in the wire(s).?
   
 
   
 
5.
 
Determine possible failure area (combination light switch, others):
Determine possible failure area (combination light switch, others)
?1.
 
Turn the vehicle to the OFF (LOCK) mode.
   
?2.
 
Disconnect the following connector.
 
Combination light switch 12P connector
   
  
  
    
?3.
 
Connect terminals A and B with a jumper wire.
 
Terminal A
 
Combination light switch 12P connector No. 1
  
Terminal B
 
Body ground
   
  
  
 
 
Terminal A
 
Combination light switch 12P connector No. 7
  
Terminal B
 
Body ground
   
  
  
 
 
Terminal A
 
Combination light switch 12P connector No. 8
  
Terminal B
 
Body ground
   
  
  
    
?4.
 
Turn the vehicle to the ON mode.
   
?5.
 
Check the parameter(s) below with the HDS.
 
Signal
 
Current conditions
  
Values
 
Unit
   
Headlight Switch (OFF)
 
     
Headlight Switch (PARKING)
 
     
Headlight Switch (AUTO)
 
     
Headlight Switch (HEADLIGHT)
 
      
  
  
    
   
Has the data list value changed from OFF to ON?
 
6.
 
Open wire check (H/L OFF SW, H/L ON SW, PARKING LT SW, COMBI SW GND (LT) lines):
Open wire check (H/L OFF SW, H/L ON SW, PARKING LT SW, COMBI SW GND (LT) lines)
?1.
 
Turn the vehicle to the OFF (LOCK) mode.
   
?2.
 
Disconnect the following connector.
 
Under-dash fuse/relay box connector B (20P)
   
  
  
    
?3.
 
Check for continuity between test points 1 and 2 respectively.
 
Test condition
 
Vehicle OFF (LOCK) mode
  
Test point 1
 
  
Test point 2
 
Combination light switch 12P connector No. 1
   
  
  
 
 
Test point 1
 
  
Test point 2
 
Combination light switch 12P connector No. 7
   
  
  
 
 
Test point 1
 
  
Test point 2
 
Combination light switch 12P connector No. 8
   
  
  
 
 
Test point 1
 
  
Test point 2
 
Combination light switch 12P connector No. 6
   
  
  
    
   
Is there continuity?
 
  
 
Repair an open or high resistance in the wire(s).?