DTC B1646

DTC B1646  : Driver's Door LF Antenna circuit open

DTC (Keyless Access 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 .

1. Problem verification

   -1. Clear the DTCs with the HDS.

   -2. Select the KEYLESS ACCESS CONTROL UNIT from the ONE-PUSH START system select menu with the HDS, and enter the SELF CHECK.

   One-Push - KEYLESS ACCESS CONTROL UNIT - SELF CHECK

   Do the SELF CHECK.

   -4. Check for DTCs with the HDS.

   DTC Description	DTC
   B1646 Driver's Door LF Antenna circuit open

   Is DTC B1646 indicated?

   YES 

   Go to step 2.

   NO 

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

2. Keyless access/TPMS control unit FL WHEEL LF+, FL WHEEL LF- line output check

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

   -2. Disconnect the following connector.

   Left-front LF antenna/initiator 2P connector

   -3. Turn the vehicle to the ON mode.

   -4. Select KEYLESS ACCESS CONTROL UNIT from the ONE-PUSH START system select menu with the HDS, and enter FUNCTIONAL TESTS.

   One-Push - KEYLESS ACCESS CONTROL UNIT - FUNCTIONAL TESTS

   Connect the voltmeter to test points 1 and 2.

   Test condition	Vehicle ON mode Left-front LF antenna/initiator 2P connector: disconnected
   Test point 1	Left-front LF antenna/initiator 2P connector No. 2
   Test point 2	Left-front LF antenna/initiator 2P connector No. 1

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

   -6. Select DRIVER (DOOR) ANTENNA L DC OUTPUT with the HDS.

   Is there voltage?

   YES 

   Faulty left-front LF antenna/initiator; replace the left-front LF antenna/initiator - Refer to: Keyless Access LF Antenna/Initiator (Left-Front) Removal and InstallationKeyless Access LF Antenna (Front Interior) Removal and Installation .

   NO 

   Go to step 3.

3. Open wire check (FL WHEEL LF+, FL WHEEL LF- lines)

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

   -2. Connect terminals A and B with a jumper wire.

   Terminal A	Left-front LF antenna/initiator 2P connector No. 2
   Terminal B	Left-front LF antenna/initiator 2P connector No. 1

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

   -3. Disconnect the following connector.

   Keyless access/TPMS control unit connector A (32P)

   -4. Check for continuity between test points 1 and 2.

   Test condition	Vehicle OFF (LOCK) mode Keyless access/TPMS control unit connector A (32P): disconnected Left-front LF antenna/initiator 2P connector: disconnected
   Test point 1	Keyless access/TPMS control unit connector A (32P) No. 13 - Refer to: Keyless Access/TPMS Control Unit Connector for Inputs and Outputs (2022 2023) or Keyless Access/TPMS Control Unit Connector for Inputs and Outputs
   Test point 2	Keyless access/TPMS control unit connector A (32P) No. 29 - Refer to: Keyless Access/TPMS Control Unit Connector for Inputs and Outputs (2022 2023) or Keyless Access/TPMS Control Unit Connector for Inputs and Outputs

   Is there continuity?

   YES 

   The FL WHEEL LF+ and FL WHEEL LF- wires are OK. Replace the keyless access/TPMS control unit .

   NO 

   Repair an open or high resistance in the wire.