DTC B1FA2

DTC B1FA2 : Right rear heater thermistor circuit open (second row seat)

DTC Description	DTC
B1FA2 Right rear heater thermistor circuit open (second row seat)

DTC (Second Row 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 - Refer to: Body Electrical Troubleshooting - B-CAN System Diagnosis Test Mode A - Initial Communication and DTC Checks (2014 2015 2016) or Body Electrical Troubleshooting - B-CAN System Diagnosis Test Mode A - Initial Communication and DTC Checks (2017 2018 2019 2020) .
The seat heater control unit does not turn on the seat heater until the seat core temperature is 85 degrees or less. Make sure the seat core temperature is below 85 degrees before troubleshooting.

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
B1FA2 Right rear heater thermistor circuit open (second row seat)

Is DTC B1FA2 indicated?

YES

Go to step 2.

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

Seat heater check 1

-1. Disconnect the following connector.

Second row 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) modeSecond row seat heater control unit 14P connector: disconnected
Test circuit	RR R TH+, RR R TH-
Test point 1	Second row seat heater control unit 14P connector No. 12 (BRN)
Test point 2	Second row seat heater control unit 14P connector No. 6 (GRN)

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

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

Is resistance value within the range?

YES

Replace the second row seat heater control unit .

Go to step 3.

Seat heater check 2

-1. Disconnect the following connector.

Right second row seat heater connector A (4P) - Refer to: Seat Heater Replacement(Seat Heaters), or Seat Heater Replacement - Ventilated Seats(Ventilated Seats), or Seat Heater Replacement (2017 2018 2019 2020)

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

Test condition	Vehicle OFF (LOCK) modeSecond row seat heater control unit 14P connector: disconnectedRight second row seat heater connector A (4P): disconnected
Test circuit	RR R TH+, RR R TH-
Test point 1	Right second row seat heater connector A (4P) No. 3

Test point 2

Right second row seat heater connector A (4P) No. 2

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

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

Is resistance value within the range?

YES

Replace the second row seat heater control unit .

Go to step 4.

Open wire check (RR R TH+ line)

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

Terminal A	Right second row seat heater connector A (4P) No. 3 (BRN)
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) modeSecond row seat heater control unit 14P connector: disconnectedRight second row seat heater connector A (4P): disconnected
Test circuit	RR R TH+
Test point 1	Second row seat heater control unit 14P connector No. 12 (BRN)
Test point 2	Body ground

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

Is there continuity?

YES

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

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