DTC B1FA0

DTC B1FA0  : Left rear heater thermistor circuit open (rear seat)

DTC (Rear Seat Heater Control Unit)

NOTE: 

• If you are troubleshooting multiple DTCs, be sure to follow the instructions in B-CAN System Diagnosis Test Mode A .
• The seat heater control unit does not turn on the seat heater until the seat core temperature is 85°ees or less. Make sure the seat core temperature is below 85°ees before troubleshooting.

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 90 seconds.

   -4. Check for DTCs with the HDS.

   DTC Description	DTC
   B1FA0 Left rear heater thermistor circuit open (rear seat)

   Is DTC B1FA0 indicated?

   YES 

   Go to step 2.

   NO 

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

2. Seat heater thermistor check 1

   -1. Disconnect the following connector.

   Rear seat heater control unit 14P connector

   -2. Measure the resistance between test points 1 and 2, refer to the following table.

   Test condition	Vehicle OFF (LOCK) mode Rear seat heater control unit 14P connector: disconnected
   Test point 1	Rear seat heater control unit 14P connector No. 13
   Test point 2	Rear seat heater control unit 14P connector No. 7

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

   Is resistance value within the range?

   YES 

   Replace the rear seat heater control unit .

   NO 

   Go to step 3.

3. Seat heater thermistor check 2

   -1. Disconnect the following connector.

   Left rear seat heater connector A (4P)

   -2. Measure the resistance between test points 1 and 2, refer to the following table.

   Test condition	Vehicle OFF (LOCK) mode Rear seat heater control unit 14P connector: disconnected Left rear seat heater connector A (4P): disconnected
   Test point 1	Left rear seat heater connector A (4P) (female terminals) No. 3:
   Test point 2	Left rear seat heater connector A (4P) (female terminals) No. 2:

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

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

   Is resistance value within the range?

   YES 

   Go to step 4.

   NO 

   Faulty left rear seat heater thermistor; replace the left rear seat-back heater .

4. Open wire check (RR L TH+ line)

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

   Terminal A	Left rear seat heater connector A (4P) (male terminals) No. 3:
   Terminal B	Body ground

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

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

   Test condition	Vehicle OFF (LOCK) mode Rear seat heater control unit 14P connector: disconnected Left rear seat heater connector A (4P): disconnected
   Test point 1	Rear seat heater control unit 14P connector No. 13
   Test point 2	Body ground

   Is there continuity?

   YES 

   Repair an open or high resistance in the RR L TH- wire.

   NO 

   Repair an open or high resistance in the RR L TH+ wire.