DTC B2646 (2020 2021)

DTC B2646  : Front sensor power failure

NOTE: 

• If you are troubleshooting multiple DTCs, be sure to follow the instructions in B-CAN System Diagnosis Test Mode A .
• The connection order of the sensor is 1st -> 2nd -> 3rd -> 4th from the side near the control unit.

DTC (Parking and Back-Up Sensor Control Unit)

1. Problem verification

   -1. Clear the DTCs with the HDS.

   -2. Turn the vehicle to the OFF (LOCK) mode and then the ON mode.

   -3. Wait for at least 6 seconds.

   -4. Check for DTCs with the HDS.

   DTC Description	DTC
   B2646 Front sensor power failure

   Is DTC B2646 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 (BOF SIDE L, E1 SIDE L lines) 1

   -1. Disconnect the following connector.

   Parking and back-up sensor control unit 16P connector

   -2. Measure the resistance between test points 1 and 2.

   Test condition	Vehicle OFF (LOCK) mode Parking and back-up sensor control unit 16P connector: disconnected
   Test point 1	Parking and back-up sensor control unit 16P connector No. 7
   Test point 2	Parking and back-up sensor control unit 16P connector No. 13

   Is there 1.0 MΩ or more?

   YES 

   Go to step 12.

   NO: with front center sensor

   Go to step 3.

   NO: without front center sensor

   Go to step 5.

3. Shorted wire check (BOF SIDE R, E1 SIDE R lines) 1

   -1. Disconnect the following connector.

   Right front center sensor 6P connector

   -2. Measure the resistance between test points 1 and 2.

   Test condition	Vehicle OFF (LOCK) mode Parking and back-up sensor control unit 16P connector: disconnected Right front center sensor 6P connector: disconnected
   Test point 1	Right front center sensor 6P connector (female terminals) No. 5:
   Test point 2	Right front center sensor 6P connector (female terminals) No. 1:

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

   Is there 1.0 MΩ or more?

   YES 

   Go to step 7.

   NO 

   Go to step 4.

4. Shorted wire check (BOF SIDE R, E1 SIDE R lines) 2

   -1. Disconnect the following connector.

   Right front corner sensor 6P connector

   -2. Measure the resistance between test points 1 and 2.

   Test condition	Vehicle OFF (LOCK) mode Parking and back-up sensor control unit 16P connector: disconnected Right front center sensor 6P connector: disconnected Right front corner sensor 6P connector: disconnected
   Test point 1	Right front center sensor 6P connector (female terminals) No. 5:
   Test point 2	Right front center sensor 6P connector (female terminals) No. 1:

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

   Is there 1.0 MΩ or more?

   YES 

   Replace the right front corner sensor .

   NO 

   Repair a short in the BOF SIDE R and E1 SIDE R wires.

5. Shorted wire check (BOF CTR L, E1 CTR L lines) 1

   -1. Disconnect the following connector.

   Left front corner sensor 6P connector

   -2. Measure the resistance between test points 1 and 2.

   Test condition	Vehicle OFF (LOCK) mode Parking and back-up sensor control unit 16P connector: disconnected Left front corner sensor 6P connector: disconnected
   Test point 1	Left front corner sensor 6P connector (female terminals) No. 5:
   Test point 2	Left front corner sensor 6P connector (female terminals) No. 1:

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

   Is there 1.0 MΩ or more?

   YES 

   Go to step 11.

   NO 

   Go to step 6.

6. Shorted wire check (BOF SIDE R, E1 SIDE R lines) 2

   -1. Disconnect the following connector.

   Right front corner sensor 6P connector

   -2. Measure the resistance between test points 1 and 2.

   Test condition	Vehicle OFF (LOCK) mode Parking and back-up sensor control unit 16P connector: disconnected Left front corner sensor 6P connector: disconnected Right front corner sensor 6P connector: disconnected
   Test point 1	Left front corner sensor 6P connector (female terminals) No. 5:
   Test point 2	Left front corner sensor 6P connector (female terminals) No. 1:

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

   Is there 1.0 MΩ or more?

   YES 

   Replace the right front corner sensor .

   NO 

   Repair a short in the BOF SIDE R and E1 SIDE R wires.

7. Shorted wire check (BOF CTR R, E1 CTR R lines) 1

   -1. Reconnect the following connector.

   Right front center sensor 6P connector

   -2. Disconnect the following connector.

   Left front center sensor 6P connector

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

   Test condition	Vehicle OFF (LOCK) mode Parking and back-up sensor control unit 16P connector: disconnected Left front center sensor 6P connector: disconnected
   Test point 1	Left front center sensor 6P connector (female terminals) No. 5:
   Test point 2	Left front center sensor 6P connector (female terminals) No. 1:

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

   Is there 1.0 MΩ or more?

   YES 

   Go to step 9.

   NO 

   Go to step 8.

8. Shorted wire check (BOF CTR R, E1 CTR R lines) 2

   -1. Disconnect the following connector.

   Right front center sensor 6P connector

   -2. Measure the resistance between test points 1 and 2.

   Test condition	Vehicle OFF (LOCK) mode Parking and back-up sensor control unit 16P connector: disconnected Left front center sensor 6P connector: disconnected Right front center sensor 6P connector: disconnected
   Test point 1	Left front center sensor 6P connector (female terminals) No. 5:
   Test point 2	Left front center sensor 6P connector (female terminals) No. 1:

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

   Is there 1.0 MΩ or more?

   YES 

   Replace the right front center sensor .

   NO 

   Repair a short in the BOF CTR R and E1 CTR R wires.

9. Shorted wire check (BOF CTR L, E1 CTR L lines) 1

   -1. Reconnect the following connector.

   Left front center sensor 6P connector

   -2. Disconnect the following connector.

   Left front corner sensor 6P connector

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

   Test condition	Vehicle OFF (LOCK) mode Parking and back-up sensor control unit 16P connector: disconnected Left front corner sensor 6P connector: disconnected
   Test point 1	Left front corner sensor 6P connector (female terminals) No. 5:
   Test point 2	Left front corner sensor 6P connector (female terminals) No. 1:

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

   Is there 1.0 MΩ or more?

   YES 

   Go to step 11.

   NO 

   Go to step 10.

10. Shorted wire check (BOF CTR L, E1 CTR L lines) 2

    -1. Disconnect the following connector.

    Left front center sensor 6P connector

    -2. Measure the resistance between test points 1 and 2.

    Test condition	Vehicle OFF (LOCK) mode Parking and back-up sensor control unit 16P connector: disconnected Left front corner sensor 6P connector: disconnected Left front center sensor 6P connector: disconnected
    Test point 1	Left front corner sensor 6P connector (female terminals) No. 5:
    Test point 2	Left front corner sensor 6P connector (female terminals) No. 1:

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

    Is there 1.0 MΩ or more?

    YES 

    Replace the left front center sensor .

    NO 

    Repair a short in the BOF CTR L and E1 CTR L wires.

11. Shorted wire check (BOF SIDE L, E1 SIDE L lines) 2

    -1. Measure the resistance between test points 1 and 2.

    Test condition	Vehicle OFF (LOCK) mode Parking and back-up sensor control unit 16P connector: disconnected Left front corner sensor 6P connector: disconnected
    Test point 1	Parking and back-up sensor control unit 16P connector No. 7
    Test point 2	Parking and back-up sensor control unit 16P connector No. 13

    Is there 1.0 MΩ or more?

    YES 

    Replace the left front corner sensor .

    NO 

    Repair a short in the BOF SIDE L and E1 SIDE L wires.

12. Shorted wire check (BOF SIDE L line)

    -1. Measure the resistance between test points 1 and 2.

    Test condition	Vehicle OFF (LOCK) mode Parking and back-up sensor control unit 16P connector: disconnected
    Test point 1	Parking and back-up sensor control unit 16P connector No. 7
    Test point 2	Body ground

    Is there 1.0 MΩ or more?

    YES 

    Replace the parking and back-up sensor control unit .

    NO 

    Repair a short to ground in the BOF SIDE L wire.