DTC B12F3

DTC B12F3  : Power Control Unit Lost Communication with Transmission Control Unit

NOTE: 

• If you are troubleshooting multiple DTCs, be sure to follow the instructions in B-CAN System Diagnosis Test Mode A .
• Before troubleshooting, make sure the fuses and relays associated with the system is OK.

DTC (Keyless Access Power Control Unit)

1. Problem verification 1

   -1. Clear the DTCs with the HDS.

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

   -3. Check for DTCs with the HDS.

   DTC Description	DTC
   B12F3 Power Control Unit Lost Communication with Transmission Control Unit

   Is DTC B12F3 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_BACKUP_FI-ECU line)

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

   -2. Disconnect the following connector.

   Park pawl actuator drive unit 26P connector

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

   Test condition	Vehicle OFF (LOCK) mode Park pawl actuator drive unit 26P connector: disconnected
   Test point 1	Park pawl actuator drive unit 26P connector No. 13
   Test point 2	Body ground

   Is there battery voltage?

   YES 

   The +B_BACKUP_FI-ECU wire is OK. Go to step 3.

   NO 

   Repair an open or high resistance in the wire.

3. Open wire check (IG1_SRS2 line)

   -1. Turn the vehicle to the ON mode.

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

   Test condition	Vehicle OFF (LOCK) mode Park pawl actuator drive unit 26P connector: disconnected
   Test point 1	Park pawl actuator drive unit 26P connector No. 15
   Test point 2	Body ground

   Is there battery voltage?

   YES 

   The IG1_SRS2 wire is OK. Go to step 4.

   NO 

   Repair an open or high resistance in the wire.

4. Open wire check (GND lines)

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

   -2. Measure the resistance between test points 1 and 2 individually.

   Test condition	Vehicle OFF (LOCK) mode Park pawl actuator drive unit 26P connector: disconnected
   Test point 1	Park pawl actuator drive unit 26P connector No. 2
   Test point 2	Body ground

   Test point 1	Park pawl actuator drive unit 26P connector No. 3
   Test point 2	Body ground

   Test point 1	Park pawl actuator drive unit 26P connector No. 17
   Test point 2	Body ground

   Test point 1	Park pawl actuator drive unit 26P connector No. 18
   Test point 2	Body ground

   Is there 1.0 Ω or less?

   YES 

   The GND wires are OK. Go to step 5.

   NO 

   Repair an open or high resistance in the ground wire or poor ground (G251).

5. Shorted wire check (IGN_TRX line)

   -1. Disconnect the following connector.

   Body control module connector G (32P)

   -2. Measure the resistance between test points 1 and 2.

   Test condition	Vehicle OFF (LOCK) mode Park pawl actuator drive unit 26P connector: disconnected Body control module connector G (32P): disconnected
   Test point 1	Park pawl actuator drive unit 26P connector No. 9
   Test point 2	Body ground

   Is there 1.0 MΩ or more?

   YES 

   The IGN_TRX wire is not shorted. Go to step 6.

   NO 

   Repair a short to ground in the wire.

6. Open wire check (IGN_TRX line)

   -1. Measure the resistance between test points 1 and 2.

   Test condition	Vehicle OFF (LOCK) mode Park pawl actuator drive unit 26P connector: disconnected Body control module connector G (32P): disconnected
   Test point 1	Body control module connector G (32P) No. 28
   Test point 2	Park pawl actuator drive unit 26P connector No. 9

   Is there 1.0 Ω or less?

   YES 

   The IGN_TRX wire is OK. Go to step 7.

   NO 

   Repair an open or high resistance in the wire.

7. Keyless access system check:

   Reconnect these items:

   • Park pawl actuator drive unit 26P connector
   • Body control module connector G (32P)

   -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 (7.9 in) away from the vehicle.

   -8. Close all doors, then press the power switch.

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

   -10.

   Touch the power switch with the keyless remote. The buttons on the keyless remote should be facing you.

   -11.

   Press the power switch, and turn the vehicle to the ON mode.

   Does the mode change to ON?

   YES 

   Go to step 8.

   NO 

   Replace the body control module .

8. Problem verification 2

   -1. Clear the DTCs with the HDS.

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

   -3. Check for DTCs with the HDS.

   DTC Description	DTC
   B12F3 Power Control Unit Lost Communication with Transmission Control Unit

   Is DTC B12F3 indicated?

   YES 

   Replace the park pawl actuator drive unit .

   NO 

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