LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Honda >> 2021 >> Clarity Plug-In Hybrid >> Repair and Diagnosis >> Accessories & Equipment >> Anti-Theft Systems >> Keyless Access (Power Control Unit) - Diagnostics (Plug-In) >> Troubleshooting >> DTC Troubleshooting: B12F3
April 5, 2026: LEMON Manuals is launched! Read the announcement.

DTC Troubleshooting: B12F3

DTC B12F3  : TCU not respond on IGNTRX

NOTE:  If you are troubleshooting multiple DTCs, be sure to follow the instructions in B-CAN System Diagnosis Test Mode A .

DTC Description DTC
B12F3 TCU not respond on IGNTRX  

DTC (Power Control Unit)

NOTE: 

  1. Problem verification

    -1. Clear the DTCs with the HDS.

    -2. Do this procedure 10 times: Press the power switch button to select the OFF (LOCK), ACCESSORY, ON, and OFF (LOCK) mode.

    -3. Check for DTCs with the HDS.

    DTC Description DTC
    B12F3 TCU not respond on IGNTRX  

    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 P-ACT DRV line)

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

    -2. Disconnect the following connector.

    Park pawl actuator driver unit 26P connector

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

    Test condition Vehicle OFF (LOCK) mode

    Park pawl actuator driver unit 26P connector: disconnected

    Test point 1 Park pawl actuator driver unit 26P connector No. 13
    Test point 2 Body ground

    Is there battery voltage?

    YES 

    The +B P-ACT DRV wire is OK. Go to step 3.

    NO 

    Repair an open or high resistance in the wire.

  3. Open wire check (IG1 P-DRV line)

    -1. Turn the vehicle to the ON mode.

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

    Test condition Vehicle ON mode

    Park pawl actuator driver unit 26P connector: disconnected

    Test point 1 Park pawl actuator driver unit 26P connector No. 15
    Test point 2 Body ground

    Is there battery voltage?

    YES 

    The IG1 P-DRV 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. Check for continuity between test points 1 and 2.

    Test condition Vehicle OFF (LOCK) mode

    Park pawl actuator driver unit 26P connector: disconnected

    Test point 1 Park pawl actuator driver unit 26P connector No. 2
    Test point 2 Body ground
    Test point 1 Park pawl actuator driver unit 26P connector No. 3
    Test point 2 Body ground
    Test point 1 Park pawl actuator driver unit 26P connector No. 17
    Test point 2 Body ground
    Test point 1 Park pawl actuator driver unit 26P connector No. 18
    Test point 2 Body ground

    Is there continuity?

    YES 

    The GND wires are OK. Go to step 5.

    NO 

    Repair an open or high resistance in the ground wire or poor ground (G206).

  5. Shorted wire check (IGNTRX line)

    -1. Disconnect the following connector.

    Body control module connector G (32P)

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

    Test condition Vehicle OFF (LOCK) mode

    Park pawl actuator driver unit 26P connector: disconnected

    Body control module connector G (32P): disconnected

    Test point 1 Park pawl actuator driver unit 26P connector No. 9
    Test point 2 Body ground

    Is there continuity?

    YES 

    Repair a short to ground in the wire.

    NO 

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

  6. Open wire check (IGNTRX line)

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

    Test condition Vehicle OFF (LOCK) mode

    Park pawl actuator driver unit 26P connector: disconnected

    Body control module connector G (32P): disconnected

    Test point 1 Park pawl actuator driver unit 26P connector No. 9
    Test point 2 Body control module connector G (32P) No. 28

    Is there continuity?

    YES 

    The IGNTRX 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 driver 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 (8.0 in) away from the vehicle.

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

    -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 button, 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 10 times: Press the power switch button to select the OFF (LOCK), ACCESSORY, ON, and OFF (LOCK) mode.

    -3. Check for DTCs with the HDS.

    DTC Description DTC
    B12F3 TCU not respond on IGNTRX  

    Is DTC B12F3 indicated?

    YES 

    Replace the park pawl actuator driver unit .

    NO 

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