DTC B12F1: Power Control Unit Lost Communication With Backup Control Unit (2013-18)

DTC (Power Control Unit)

1. Problem verification 1:

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

   - 2. Clear the DTCs with the HDS.

   Clear DTCs

   - 3. Do this procedure 10 times: Press the engine start/stop button to select the OFF, ACC, ON, and OFF mode.

   - 4. Check for DTCs with the HDS.

   DTC Description	DTC
   B12F1 Power Control Unit Lost Communication With Backup Control Unit

   Is DTC B12F1 indicated?

   YES 

   Go to step 2.

   NO 

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

2. DTC check:

   Check for Backup Control Unit DTCs with the HDS.

   DTC Description	DTC

   Are any DTCs indicated?

   YES 

   Go to the indicated DTC's troubleshooting.

   NO 

   Go to step 3.

3. Shorted wire check (IGN TRX line):

   Press the engine start/stop button to select the OFF mode.

   - 2. Disconnect the following connectors.

   Power control unit connector C (36P)Backup control unit 40P connectorKeyless access control unit connector B (32P)Electric steering lock 12P connector

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

   Test condition	OFF modePower control unit connector C (36P): disconnectedBackup control unit 40P connector: disconnectedKeyless access control unit connector B (32P): disconnectedElectric steering lock 12P connector: disconnected
   Test circuit	IGN TRX
   Test point 1	Power control unit connector C (36P) No. 17 (BRN)
   Test point 2	Body ground

   Courtesy of HONDA, U.S.A., INC.

   Is there continuity?

   YES 

   Repair a short to ground in the wire.

   NO 

   The IGN TRX wire is not shorted. Go to step 4.

4. Open wire check (IGN TRX line):

   Check for continuity between test points 1 and 2.

   Test condition	OFF modePower control unit connector C (36P): disconnectedBackup control unit 40P connector: disconnectedKeyless access control unit connector B (32P): disconnectedElectric steering lock 12P connector: disconnected
   Test circuit	IGN TRX
   Test point 1	Backup control unit 40P connector No. 29 (BRN)
   Test point 2	Power control unit connector C (36P) No. 17 (BRN)

   Courtesy of HONDA, U.S.A., INC.

   Is there continuity?

   YES 

   The IGN TRX wire is OK. Go to step 5.

   NO 

   Repair an open or high resistance in the wire.

5. Power control unit and backup control unit communication check:

   Reconnect these items:

   • Electric steering lock 12P connector
   • Power control unit connector C (36P)
   • Backup control unit 40P connector
   • Keyless access control unit connector B (32P)

   - 2. Do the battery terminal disconnection procedure .

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

   - 4. Do the battery terminal reconnection procedure .

   - 5. With driver's power window open, and all the doors closed, press the engine start/stop button to select the OFF mode.

   - 6. Remove all the keyless remotes from inside the vehicle by holding them outside of the open driver's window, at least 7.87 in (20 cm) from the vehicle.

   - 7. Press the engine start/stop button. The MID will request the remote to touch the start/stop switch. The LED on the start/stop switch will flash after the first push, up to 30 seconds.

   - 8. Touch the engine start/stop switch with the keyless remote. The buttons on the keyless remote should be facing you. The LED on the start/stop switch will turn solid when detected.

   - 9. Press and hold the engine start/stop button to select the ON mode.

   Does the mode change to ON?

   YES 

   Go to step 6.

   NO 

   Go to step 7.

6. Problem verification 2:

   Clear the DTCs with the HDS.

   Clear DTCs

   - 2. With driver's power window open, and all the doors closed, press the engine start/stop button to select the OFF mode.

   - 3. Remove all the keyless remotes from inside the vehicle by holding them outside of the open driver's window, at least 7.87 in (20 cm) from the vehicle.

   - 4. Press the engine start/stop button. The MID will request the remote to touch the start/stop switch. The LED on the start/stop switch will flash after the first push, up to 30 seconds.

   - 5. Touch the engine start/stop switch with the keyless remote. The buttons on the keyless remote should be facing you. The LED on the start/stop switch will turn solid when detected.

   - 6. Check for DTCs with the HDS.

   DTC Description	DTC
   B12F1 Power Control Unit Lost Communication With Backup Control Unit

   Is DTC B12F1 indicated?

   YES 

   Replace the backup control unit .

   NO 

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

7. Backup control unit communication status check:

   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

   Is only Status with BACKUP CONTROL UNIT 1 value indicated?

   YES 

   Replace the backup control unit .

   NO 

   Replace the power control unit .