Lexus RX (RX 350L, RX450h) 2016-2025 Repair Manual: Lost Communication with Rear Panel LIN (B14B3)
DESCRIPTION
The refreshing seat switch (for rear side)*1 or rear seat heater switch*2 communicates with the air conditioning amplifier assembly via LIN communication.
If the LIN communication system is malfunctioning, the air conditioning amplifier assembly will not operate even if the refreshing seat switch (for rear side)*1 or rear seat heater switch*2 is operated.
- *1: w/o Rear No. 2 Seat
- *2: w/ Rear No. 2 Seat
| DTC No. | Detection Item | DTC Detection Condition | Trouble Area |
|---|---|---|---|
| B14B3 | Lost Communication with Rear Panel LIN | Lost communication with the refreshing seat switch*1 or rear seat heater switch*2 |
|
- *1: w/o Rear No. 2 Seat
- *2: w/ Rear No. 2 Seat
WIRING DIAGRAM
CAUTION / NOTICE / HINT
NOTICE:
Inspect the fuses for circuits related to this system before performing the following procedure.
PROCEDURE
| 1. | CLEAR DTC |
(a) Clear the DTCs.
Click here .gif)
|
.gif)
| 2. | CHECK FOR DTC |
(a) Check for DTCs.
Click here
OK:
DTC B14B3 is not output.
| Result | Proceed to |
|---|---|
| OK | A |
| NG (w/o Rear No. 2 Seat) | B |
| NG (w/ Rear No. 2 Seat) | C |
| A | .gif) | USE SIMULATION METHOD TO CHECK |
| C | | GO TO STEP 8 |
|
| 3. | CHECK HARNESS AND CONNECTOR (IG POWER SUPPLY - REFRESHING SEAT SWITCH (FOR REAR SIDE) - BODY GROUND) |
| (a) Disconnect the J15 refreshing seat switch (for rear side) connector. |
|
(b) Measure the voltage and resistance according to the value(s) in the table below.
Standard Voltage:
| Tester Connection | Condition | Specified Condition |
|---|---|---|
| J15-1 (IG) - Body ground | Engine switch on (IG) | 11 to 14 V |
| J15-1 (IG) - Body ground | Engine switch off | Below 1 V |
Standard Resistance:
| Tester Connection | Condition | Specified Condition |
|---|---|---|
| J15-5 (E) - Body ground | Always | Below 1 Ω |
| NG | | REPAIR OR REPLACE HARNESS OR CONNECTOR |
|
| 4. | CHECK HARNESS AND CONNECTOR (AIR CONDITIONING AMPLIFIER ASSEMBLY - REFRESHING SEAT SWITCH) |
(a) Disconnect the 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 |
|---|---|---|
| J48-24 (RLIN) - J15-3 (RLIN) | Always | Below 1 Ω |
| J48-24 (RLIN) or J15-3 (RLIN) - Body ground | Always | 10 kΩ or higher |
| NG | | REPAIR OR REPLACE HARNESS OR CONNECTOR |
|
| 5. | REPLACE REFRESHING SEAT SWITCH (FOR REAR SIDE) |
(a) Temporarily replace the refreshing seat switch (for rear side) with a new or known good one.
Click here
|
| 6. | CLEAR DTC |
(a) Clear the DTCs.
Click here
|
| 7. | CHECK FOR DTC |
(a) Check for DTCs.
Click here
OK:
DTC B14B3 is not output.
| OK | | END (REFRESHING SEAT SWITCH (FOR REAR SIDE) WAS DEFECTIVE) |
| NG | | REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY |
| 8. | CHECK HARNESS AND CONNECTOR (IG POWER SUPPLY - REAR SEAT HEATER SWITCH - BODY GROUND) |
| (a) Disconnect the V4 rear seat heater switch connector. |
|
(b) Measure the voltage and resistance according to the value(s) in the table below.
Standard Voltage:
| Tester Connection | Condition | Specified Condition |
|---|---|---|
| V4-1 (IG) - Body ground | Engine switch on (IG) | 11 to 14 V |
| V4-1 (IG) - Body ground | Engine switch off | Below 1 V |
Standard Resistance:
| Tester Connection | Condition | Specified Condition |
|---|---|---|
| V4-5 (E) - Body ground | Always | Below 1 Ω |
| NG | | REPAIR OR REPLACE HARNESS OR CONNECTOR |
|
| 9. | CHECK HARNESS AND CONNECTOR (AIR CONDITIONING AMPLIFIER ASSEMBLY - REAR SEAT HEATER SWITCH) |
(a) Disconnect the 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 |
|---|---|---|
| J48-24 (RLIN) - V4-3 (RLIN) | Always | Below 1 Ω |
| J48-24 (RLIN) or V4-3 (RLIN) - Body ground | Always | 10 kΩ or higher |
| NG | | REPAIR OR REPLACE HARNESS OR CONNECTOR |
|
| 10. | REPLACE REAR SEAT HEATER SWITCH |
(a) Temporarily rear seat heater switch with a new or known good one.
Click here
|
| 11. | CLEAR DTC |
(a) Clear the DTCs.
Click here
|
| 12. | CHECK FOR DTC |
(a) Check for DTCs.
Click here
OK:
DTC B14B3 is not output.
| OK | | END (REAR SEAT HEATER SWITCH WAS DEFECTIVE) |
| NG | | REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY |
Data List / Active Test
DATA LIST / ACTIVE TEST DATA LIST HINT: Using the Techstream to read the Data List allows the values or states of switches, sensors, actuators and other items to be read without removing any parts. Th ...
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Lexus RX (RX 350L, RX450h) 2016-{YEAR} Owners Manual
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Lexus RX (RX 350L, RX450h) 2016-{YEAR} Repair Manual
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