DTC B1641: RF2 Unit Transmitter/receiver Circuit Malfunction

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
   B1641 RF2 unit transmitter/receiver circuit malfunction

   Is DTC B1641 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 (RF TRX PWR, RF TRX GND, RF TRX UART lines)

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

   - 2. Disconnect the following connectors.

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

   2-way transceiver connector A (3P)

   - 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 2-way transceiver connector A (3P): disconnected
   Test point 1	Keyless access/TPMS control unit connector A (32P) No. 4
   Test point 2	Body ground

   Test point 1	Keyless access/TPMS control unit connector A (32P) No. 5
   Test point 2	Body ground

   Test point 1	Keyless access/TPMS control unit connector A (32P) No. 6
   Test point 2	Body ground

   Is there continuity?

   YES 

   Repair a short to ground in the wire.

   NO 

   The RF TRX PWR, RF TRX GND, and RF TRX UART wires are not shorted. Go to step 3.

3. Open wire check (RF TRX PWR, RF TRX GND, RF TRX UART lines)

   -1. Connect terminals A and B with a jumper wire.

   Terminal A	2-way transceiver connector A (3P) No. 1
   Terminal B	Body ground

   Terminal A	2-way transceiver connector A (3P) No. 2
   Terminal B	Body ground

   Terminal A	2-way transceiver connector A (3P) No. 3
   Terminal B	Body ground

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

   - 2. 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 2-way transceiver connector A (3P): disconnected
   Test point 1	Keyless access/TPMS control unit connector A (32P) No. 4
   Test point 2	Body ground

   Test point 1	Keyless access/TPMS control unit connector A (32P) No. 5
   Test point 2	Body ground

   Test point 1	Keyless access/TPMS control unit connector A (32P) No. 6
   Test point 2	Body ground

   Is there continuity?

   YES 

   The RF TRX PWR, RF TRX GND, and RF TRX UART wires are OK. Go to step 4.

   NO 

   Repair an open or high resistance in the wire.

4. Keyless access/TPMS control unit RF TRX PWR line output check

   -1. Reconnect the following connector.

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

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

   Test point 1	2-way transceiver connector A (3P) No. 1
   Test point 2	Body ground

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

   - 3. Select the KEYLESS ACCESS CONTROL UNIT from the ONE-PUSH START system select menu with the HDS, and enter the FUNCTIONAL TESTS, and do the RF1 RXVCC DRIVING.

   One-Push - KEYLESS ACCESS CONTROL UNIT - FUNCTIONAL TESTS

   the voltage change from about 0 V to battery voltage?

   YES 

   Check for loose or poor connection. If the connection is OK, replace the 2-way transceiver .

   NO 

   Check for loose or poor connection. If the connection is OK, replace the keyless access/TPMS control unit .