DTC B12F0: Power control unit lost communication with electric steering lock

DTC (Power Control Unit)

NOTE:  If you are troubleshooting multiple DTCs, be sure to follow the instructions in B-CAN System Diagnosis Test Mode A - Refer to: Body Electrical Troubleshooting - B-CAN System Diagnosis Test Mode A - Initial Communication and DTC Checks .

Before troubleshooting, make sure the No. C32 (15 A) and No. C3 (10 A) fuses in the under-dash fuse/relay box are OK.

1. Problem verification 1:

   - 1. Turn the vehicle to the ON mode.

   - 2. Clear the DTCs with the HDS.

   - 3. Do this procedure 10 times: Turn the vehicle to the OFF (LOCK) mode, ACCESSORY mode, ON mode, and OFF (LOCK) mode.

   - 4. Turn the vehicle to the ON mode.

   - 5. Check for DTCs with the HDS.

   DTC Description	DTC
   B12F0 Power control unit lost communication with electric steering lock

   Is DTC B12F0 indicated?

   YES 

   Go to step 2.

   NO 

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

2. Open wire check (+B SMART line):

   - 1. Turn the vehicle to the OFF (LOCK) mode.

   - 2. Disconnect the following connector.

   Electric steering lock 12P connector

   - 3. Measure the voltage between test points 1 and 2.

   Test condition	Vehicle OFF (LOCK) mode. Electric steering lock 12P connector: disconnected
   Test point 1	Electric steering lock 12P connector No. 3
   Test point 2	Body ground

   Is there battery voltage?

   YES 

   The +B SMART wire is OK. Go to step 3.

   NO 

   Repair an open or high resistance in the wire.

3. Open wire check (GND line):

   Check for continuity between test points 1 and 2.

   Test condition	Vehicle OFF (LOCK) mode. Electric steering lock 12P connector: disconnected
   Test point 1	Electric steering lock 12P connector No. 7
   Test point 2	Body ground

   Is there continuity?

   YES 

   The GND wire is OK. Go to step 4.

   NO 

   Repair an open or high resistance in the ground wire or poor ground (G401).

4. Shorted wire check (IGN TRX line):

   - 1. Disconnect the following connector.

   Keyless access control unit connector C (20P)

   - 2. Check for continuity between test points 1 and 2.

   Test condition	Vehicle OFF (LOCK) mode Electric steering lock 12P connector: disconnected Keyless access control unit connector C (20P): disconnected
   Test point 1	Electric steering lock 12P connector No. 6
   Test point 2	Body ground

   Is there continuity?

   YES 

   Repair a short to ground in the wire.

   NO 

   The IGN TRX wire is not shorted. Go to step 5.

5. Open wire check (IGN TRX line):

   - 1. Check for continuity between test points 1 and 2.

   Test condition	Vehicle OFF (LOCK) mode Electric steering lock 12P connector: disconnected Keyless access control unit connector C (20P): disconnected
   Test point 1	Electric steering lock 12P connector No. 6
   Test point 2	Keyless access control unit connector C (20P) No. 3

   Is there continuity?

   YES 

   The IGN TRX wire is OK. Go to step 6.

   NO 

   Repair an open or high resistance in the wire.

6. Power control unit and electric steering lock communication check:

   - 1. Reconnect the following connectors.

   Electric steering lock 12P connector

   Keyless access control unit connector C (20P)

   - 2. With driver's power window open, turn the vehicle to the OFF (LOCK) mode.

   - 3. Do the 12 volt battery terminal disconnection procedure .

   - 4. Wait for at least 10 seconds to clear the DTCs.

   - 5. Do the 12 volt battery terminal reconnection procedure .

   - 6. Turn the vehicle to the ON mode then the OFF (LOCK) mode.

   - 7. Remove all the keyless remotes from inside the vehicle. Hold them outside the open driver's window, at least 20 cm (8.0 in) away from the vehicle.

   - 8. Close all doors, then press the engine start/stop switch.

   - 9. The keyless remotes bring to the vehicle inside, during close all doors.

   Touch the engine start/stop switch with the keyless remote. The buttons on the keyless remote should be facing you.

   Turn the vehicle to the ON mode.

   Does the mode change to ON?

   YES 

   Go to step 7.

   NO 

   Go to step 8.

7. Problem verification 2:

   - 1. Clear the DTCs with the HDS.

   - 2. Do this procedure 10 times: Turn the vehicle to the OFF (LOCK) mode, ACCESSORY mode, ON mode, and OFF (LOCK) mode.

   - 3. Turn the vehicle to the ON mode.

   - 4. Check for DTCs with the HDS.

   DTC Description	DTC
   B12F0 Power control unit lost communication with electric steering lock

   Is DTC B12F0 indicated?

   YES 

   Replace the electric steering lock.

   NO 

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

8. Electric steering lock communication status check:

   - 1. Select COMMUNICATION STATUS in the INSPECTION MENU with the HDS.

   - 2. Check the value of STATUS with ESL, STATUS with KEYLESS ACCESS CONTROL UNIT, and STATUS with BACKUP CONTROL UNIT with the HDS.

   	HDS Description	Value
   Status with ESL	MTR CUT1 (Cont) Status	1
   	MTR CUT2 (IG) Status	1
   	IG1 Input State of ESL	1
   	MTRCONT Status of ESL	1
   	ESL Motor Status	1
   	Switch D detection for Unlock Status	1
   	Switch C detection for Unlock Status	1
   	Switch B detection for Unlock Status	1
   Status with KEYLESS ACCESS CONTROL UNIT	FOB KEY Authentication Result	1
   Status with BACKUP CONTROL UNIT	FOB KEY Authentication Result	1

   NOTE:  The parameters are displayed only when the vehicle cannot be turned to the ON mode.

   Are only Status with ESL 1 values indicated?

   YES 

   Replace the electric steering lock.

   NO 

   Replace the keyless access control unit .