DTC B1646: Driver's Door LF Antenna Circuit Open

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 ChecksBody Electrical Troubleshooting - B-CAN System Diagnosis Test Mode 1 and Test Mode 2 (without the HDS)Body Electrical Troubleshooting - B-CAN System Diagnosis Test Mode B - Control Unit Not CommunicatingBody Electrical Troubleshooting - B-CAN System Diagnosis Test Mode C - No DTCs and Output Won't Shut OFFBody Electrical Troubleshooting - B-CAN System Diagnosis Test Mode D - No DTCs and Output Won't Turn ON .

• 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.

  3. 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 control unit EXT FR DR +, EXT FR DR- line output check:

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

  2. Disconnect the following connector.

  Driver's door outer handle 8P connector

  3. Turn the vehicle to the ON mode.

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

  5. Connect the voltmeter between test points 1 and 2.

  Test point 1	Driver's door outer handle 8P connector No. 2
  Test point 2	Driver's door outer handle 8P connector No. 6

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

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

  Is there voltage?

  YES 

  Faulty driver's door LF antenna; replace the driver's door outer handle .

  NO 

  Go to step 3.

• 3. Open wire check (EXT FR DR+, EXT FR DR- lines):

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

  2. Disconnect the following connector.

  Keyless access control unit connector A (32P)

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

  Test condition	Vehicle OFF (LOCK) mode Keyless access control unit connector A (32P): disconnected Driver's door outer handle 8P connector: disconnected
  Test point 1	Keyless access control unit connector A (32P) No. 29
  Test point 2	Driver's door outer handle 8P connector No. 2

  Test point 1	Keyless access control unit connector A (36P) No. 13
  Test point 2	Driver's door outer handle 8P connector No. 6

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

  Is there continuity?

  YES 

  The EXT FR DR+ and EXT FR DR- wires are OK. Replace the keyless access control unit .

  NO 

  Repair an open or high resistance in the wire.