DTC B1645: Driver's Door LF Antenna Circuit Short

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. Turn the vehicle to the ON mode.

   - 2. Clear the DTCs with the HDS.

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

   - 4. Do the SELF CHECK.

   - 5. Check for DTCs with the HDS.

   DTC Description	DTC
   B1645 Driver's door LF antenna circuit short

   Is DTC B1645 indicated?

   YES 

   Go to step 2 below.

   NO 

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

2. Shorted wire check (EXT FR DR+, EXT FR DR- lines):

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

   - 2. Disconnect the following connectors.

   Keyless access control unit connector A (32P)

   Driver's door outer handle 8P connector

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

   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. 13
   Test point 2	Body ground

   Test point 1	Keyless access control unit connector A (32P) No. 29
   Test point 2	Body ground

   Is there continuity?

   YES 

   Repair a short to ground in the wire.

   NO 

   The EXT FR DR+ and EXT FR DR- wires are not shorted. Go to step 3 below.

3. Shorted wire check (EXT FR DR+ line to EXT FR DR- line):

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

   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. 13
   Test point 2	Keyless access control unit connector A (32P) No. 29

   Is there continuity?

   YES 

   Repair a short in EXT FR DR+ wire to EXT FR DR- wire.

   NO 

   The EXT FR DR+ and EXT FR DR- wires are OK. Go to step 4 below.

4. EXT FR DR+, EXT FR DR- line output check:

   - 1. Reconnect the following connector.

   Keyless access control unit connector A (32P)

   - 2. Turn the vehicle to the ON mode.

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

   Test condition	Vehicle ON mode
   	Driver's door outer handle 8P connector: disconnected
   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.

   Is there voltage?

   YES 

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

   NO 

   Replace the keyless access control unit .