Lexus RX (RX 350L, RX450h) 2016-2025 Repair Manual: Rear Right Seat Heat Sensor Circuit (B14C2)

DESCRIPTION

Output to the rear seat cushion heater temperature sensor stops if one of the following occurs: 1) the temperature sensor is open or shorted; or 2) the temperature sensor is damaged and its output value does not change.

DTC No.	Detection Item	DTC Detection Condition	Trouble Area
B14C2	Rear Right Seat Heat Sensor Circuit	Seat heater temperature sensor malfunction	Air conditioning amplifier assembly Rear seat cushion heater RH (seat heater assembly) Seat heater control sub-assembly (for rear RH side) Wire harness or connector

WIRING DIAGRAM

PROCEDURE

1.

CLEAR DTC

(a) Clear the DTCs.

Click here

Body Electrical > Air Conditioner > Clear DTCs

NEXT

2.	CHECK FOR DTC

(a) Check for DTCs.

Click here

Body Electrical > Air Conditioner > Trouble Codes

OK:

DTC B14C2 is not output.

OK

USE SIMULATION METHOD TO CHECK

NG

3.	INSPECT REAR SEAT CUSHION HEATER RH (SEAT HEATER ASSEMBLY)

(a) Remove the rear seat cushion heater RH (seat heater assembly).

for 60/40 Split Seat Type: Click here

for Captain Seat Type: Click here

(b) Inspect the rear seat cushion heater RH (seat heater assembly).

for 60/40 Split Seat Type: Click here

for Captain Seat Type: Click here

NG

REPLACE REAR SEAT CUSHION HEATER RH (SEAT HEATER ASSEMBLY)

OK

4.	CHECK HARNESS AND CONNECTOR (AIR CONDITIONING AMPLIFIER ASSEMBLY - REAR SEAT CUSHION HEATER RH (SEAT HEATER ASSEMBLY))

(a) Disconnect the J42 and J48 air conditioning amplifier assembly connector.

(b) Measure the resistance according to the value(s) in the table below.

Standard Resistance:

Tester Connection	Condition	Specified Condition
J42-23 (TFAR) - x5-5 (THR)	Always	Below 1 Ω
J42-23 (TFAR) or x5-5 (THR) - Body ground	Always	10 kΩ or higher
J48-21 (SG-8) - x5-2 (PR)	Always	Below 1 Ω
J48-21 (SG-8) or x5-2 (PR) - Body ground	Always	10 kΩ or higher

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

OK

5.	REPLACE SEAT HEATER CONTROL SUB-ASSEMBLY (FOR REAR RH SIDE)

(a) Temporarily replace the seat heater control sub-assembly (for rear RH side) with a new or known good one.

Click here

NEXT

6.

CLEAR DTC

(a) Clear the DTCs.

Click here

Body Electrical > Air Conditioner > Clear DTCs

NEXT

7.	CHECK FOR DTC

(a) Check for DTCs.

Click here

Body Electrical > Air Conditioner > Trouble Codes

OK:

DTC B14C2 is not output.

OK

END (SEAT HEATER CONTROL SUB-ASSEMBLY (FOR REAR RH SIDE) WAS DEFECTIVE)

NG

REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY