DTC B1649: Driver Side Rear Passenger Door Antenna Circuit Short

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 (2015-17), or Body Electrical Troubleshooting - B-CAN System Diagnosis Test Mode A - Initial Communication and DTC Checks (2018-19) .

DTC (Keyless Access Control Unit)

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
   B1649 Driver side rear passenger door antenna circuit short

   Is DTC B1649 indicated?

   YES 

   Go to step 2.

   NO 

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

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

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

   - 2. Disconnect the following connectors.

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

   Left-rear LF antenna/initiator 2P connector

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

   Test condition	Vehicle OFF (LOCK) mode Keyless access/TPMS control unit connector A (32P): disconnected Left-rear LF antenna/initiator 2P connector: disconnected
   Test point 1	Keyless access/TPMS control unit connector A (32P) No. 16
   Test point 2	Body ground

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

   Is there continuity?

   YES 

   Repair a short to ground in the wire.

   NO 

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

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

   -1. 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-rear LF antenna/initiator 2P connector: disconnected
   Test point 1	Keyless access/TPMS control unit connector A (32P) No. 16
   Test point 2	Keyless access/TPMS control unit connector A (32P) No. 32

   Is there continuity?

   YES 

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

   NO 

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

4. Keyless access/TPMS control unit EXT RR DR+, EXT RR DR- line output check

   -1. Reconnect the following connector.

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

   - 2. Turn the vehicle to the ON mode.

   - 3. Select KEYLESS ACCESS CONTROL 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-rear LF antenna/initiator 2P connector: disconnected
   Test point 1	Left-rear LF antenna/initiator 2P connector No. 2
   Test point 2	Left-rear LF antenna/initiator 2P connector No. 1

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

   - 5. Select DRIVER SIDE REAR (DOOR) ANTENNA L DC OUTPUT with the HDS.

   Is there voltage?

   YES 

   Faulty left-rear LF antenna/initiator; replace the left-rear LF antenna/initiator - Refer to: Keyless Access LF Antenna/Initiator (Left-Rear) Removal and Installation, .

   NO 

   Replace the keyless access/TPMS control unit .