DTC B1641: RF2 Unit Transmitter / Receiver Circuit Malfunction

DTC (Keyless Access Control Unit)

1. Problem verification:

   - 1. Clear the DTCs with the HDS.

   - 2. Select the MODE MENU from the HDS, then enter the SELF CHECK.

   One-Push - SMART KEY UNIT - SELF CHECK

   - 3. Do the SELF CHECK.

   - 4. Check for DTCs with the HDS.

   DTC Description	DTC
   B1641 RF2 UNIT TRANSMITTER / RECEIVER CIRCUIT MALFUNCTION

   Is DTC B1640 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 GND2, RF RXD2, RF VCC2 lines):

   - 1. Press the engine start/stop button to select the OFF mode.

   - 2. Disconnect the following connectors.

   RF unit 2 3P connector - Refer to: Keyless Access RF 2 Unit Removal and Installation .

   Keyless access control unit connector B (32P)

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

   Test condition	OFF mode; RF unit 2 3P connector: disconnected; Keyless access control unit connector B (32P): disconnected
   Test circuit	RF GND2
   Test point 1	Keyless access control unit connector B (32P) No. 18 (YEL)
   Test point 2	Body ground

   Test circuit	RF RXD2
   Test point 1	Keyless access control unit connector B (32P) No. 31 (RED)
   Test point 2	Body ground

   Test circuit	RF VCC2
   Test point 1	Keyless access control unit connector B (32P) No. 29 (WHT)
   Test point 2	Body ground

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

   Is there continuity?

   YES 

   Repair a short to ground in the wire.

   NO 

   The RF GND2, RF RXD2, and RF VCC2 wires are not shorted. Go to step 3.

3. Open wire check (RF GND2, RF RXD2, RF VCC2 lines):

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

   Test condition	OFF mode; RF unit 2 3P connector: disconnected; Keyless access control unit connector B (32P): disconnected
   Test circuit	RF GND2
   Test point 1	RF unit 2 3P connector No. 1 (YEL)
   Test point 2	Keyless access control unit connector B (32P) No. 18 (YEL)

   Test circuit	RF RXD2
   Test point 1	RF unit 2 3P connector No. 2 (RED)
   Test point 2	Keyless access control unit connector B (32P) No. 31 (RED)

   Test circuit	RF VCC2
   Test point 1	RF unit 2 3P connector No. 3 (WHT)
   Test point 2	Keyless access control unit connector B (32P) No. 29 (WHT)

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

   Is there continuity?

   YES 

   The RF GND2, RF RXD2, and RF VCC2 wires are OK. Go to step 4.

   NO 

   Repair an open or high resistance in the wire.

4. Keyless access control unit RF VCC2 line output check:

   - 1. Reconnect keyless access control unit connector B (32P) .

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

   Test point 1	RF unit 2 3P connector No. 3 (WHT)
   Test point 2	Body ground

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

   - 3. Select the FUNCTIONAL TESTS from the HDS, and do the RF2 RXVCC DRIVING.

   One-Push - SMART KEY UNIT - FUNCTIONAL TESTS

   Does the voltage change from 0 to 5 V?

   YES 

   Check for loose or poor connection. If the connection is OK, replace the RF unit 2 - Refer to: Keyless Access RF 2 Unit Removal and Installation .

   NO 

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