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. Testing and Inspection

Is the engine start/stop switch OK?
YES - Go to step 5.

NO - Replace the engine start/stop switch. Testing and Inspection


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 in the RED 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 open in the 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 individually.

Is there continuity?
YES - Replace the power control unit. Testing and Inspection

NO - Repair open in the wire.