B12C5

DTC Troubleshooting: B12C5

DTC B12C5:

Engine Start/Stop Switch Failure

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.

Is DTC B12C5 indicated?

YES -

Go to step 4.

NO -

Intermittent failure, the system is OK at this time. Check for loose or poor connections.�

4. Do the engine start/stop switch test Service and Repair.

Is the engine start/stop switch OK?

YES -

Go to step 5.

NO -

Replace the engine start/stop switch Service and Repair.�

5. Reconnect the engine start/stop switch 10P connector.

6. Measure the voltage between body ground and engine start/stop switch 10P connector terminal No. 1.





Is there battery voltage?

YES -

Go to step 7.

NO -

Check the No. 12 (10 A) fuse in the passenger's under-dash fuse/relay box. If the fuse is OK, check for an open or high resistance in the wire.�

7. Press and hold the engine start/stop button.

8. Measure the voltage between body ground and engine start/stop switch 10P connector terminal No. 4.





Is there less than 0.2 V?

YES -

Go to step 9.

NO -

Repair an open or high resistance in the ground wire or poor ground (G405).�

9. Disconnect the engine start/stop switch 10P connector.

10. Disconnect power control unit connector C (36P).

11. Check for continuity between engine start/stop switch 10P connector terminals No. 2 and No. 5, and power control unit connector C (36P) terminals No. 8 and No. 7 respectively.





Is there continuity?

YES -

Replace the power control unit.�

NO -

Repair an open or high resistance in the wire.�