DTC Troubleshooting: B12C5
DTC B12C5: Engine Start/Stop Switch Failure
DTC Description
DTC
B12C5 Engine Start/Stop Switch Failure
  

1.
Problem verification:

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


?2.
Press the engine start/stop button at least 20 times, then wait for at least 20 seconds.

?3.
Check for DTCs with the HDS.
DTC Description
DTC
B12C5 Engine Start/Stop Switch Failure
  

Is DTC B12C5 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 (+B SMART line, GND line or Engine start/stop switch, Keyless access control unit):

Determine possible failure area (+B SMART line, GND line or Engine start/stop switch, Keyless access control unit)
?1.
Press the engine start/stop button to select the OFF mode.

?2.
Disconnect the following connector.

?3.
Measure the voltage between test points 1 and 2.
Test condition
OFF mode
Test circuit
+B SMART, GND
Test point 1
Engine start/stop switch 10P connector No. 5 (RED)
Test point 2
Engine start/stop switch 10P connector No. 2 (BLK)


Is there battery voltage?

     
YES
     
     
     
The +B SMART wire is OK. Go to step 3.
     
NO
     
     
     
Go to step 6.
3.
Shorted wire check (SS2 (-), SS1 (+) lines):

Shorted wire check (SS2 (-), SS1 (+) lines)
?1.
Disconnect the following connector.

?2.
Check for continuity between test points 1 and 2 individually.
Test condition
OFF mode
Engine start/stop switch 10P connector: disconnected
Keyless access control unit connector B (28P): disconnected
Test circuit
SS2 (-)
Test point 1
Engine start/stop switch 10P connector No. 1 (GRN)
Test point 2
Body ground

Test circuit
SS1 (+)
Test point 1
Engine start/stop switch 10P connector No. 4 (BLU)
Test point 2
Body ground


Is there continuity?

     
YES
     
     
     
Repair short to ground in the wire.?
     
NO
     
     
     
The SS2 (-) and SS1 (+) wires are not shorted. Go to step 4.
4.
Open wire check (SS2 (-), SS1 (+) lines):

Open wire check (SS2 (-), SS1 (+) lines)
?1.
Check for continuity between test points 1 and 2 respectively.
Test condition
OFF mode
Engine start/stop switch 10P connector: disconnected
Keyless access control unit connector B (28P): disconnected
Test circuit
SS2 (-)
Test point 1
Engine start/stop switch 10P connector No. 1 (GRN)
Test point 2
Keyless access control unit connector B (28P) No. 8 (GRN)

Test circuit
SS1 (+)
Test point 1
Engine start/stop switch 10P connector No. 4 (BLU)
Test point 2
Keyless access control unit connector B (28P) No. 12 (BLU)


Is there continuity?

     
YES
     
     
     
The SS2 (-) and SS1 (+) wires are OK. Go to 5.
     
NO
     
     
     
Repair an open or high resistance in the wire.?
5.
Engine start/stop switch operation check:

Engine start/stop switch operation check
?1.
Do the engine start/stop switch test.

Is the engine start/stop switch OK?

     
YES
     
     
     
     
NO
     
     
     
6.
Open wire check (+B SMART line):

Open wire check (+B SMART line)
?1.
Measure the voltage between test points 1 and 2.
Test condition
OFF mode
Test circuit
+B SMART
Test point 1
Engine start/stop switch 10P connector No. 5 (RED)
Test point 2
Body ground


Is there battery voltage?

     
YES
     
     
     
Repair an open or high resistance in the ground wire or poor ground (G501).?
     
NO
     
     
     
Repair an open or high resistance in the wire.?