Lexus RX (RX 350L, RX450h) 2016-2025 Repair Manual: Lost Communication with Rear Panel LIN (B14B3)

Lexus RX (RX 350L, RX450h) 2016-2025 Repair Manual / Vehicle Interior / Heating / Air Conditioning / Air Conditioning System / Lost Communication with Rear Panel LIN (B14B3)

DESCRIPTION

The No. 2 air conditioning control assembly communicates with the air conditioning amplifier assembly via LIN communication.

If the LIN communication system is malfunctioning, the air conditioning amplifier assembly does not operate even if the No. 2 air conditioning control assembly is operated.

DTC No.

Detection Item

DTC Detection Condition

Trouble Area

Memory

B14B3

Lost Communication with Rear Panel LIN

Lost communication with No. 2 air conditioning control assembly
  • Harness or connector
  • No. 2 air conditioning control assembly
  • Air conditioning amplifier assembly

Memorized

(10 sec. or more)*
  • *: The air conditioning amplifier assembly stores this DTC if the malfunction has occurred for the period of time indicated in the brackets.

WIRING DIAGRAM

CAUTION / NOTICE / HINT

NOTICE:

Inspect the fuses for circuits related to this system before performing the following procedure.

PROCEDURE

1.

CHECK HARNESS AND CONNECTOR (NO. 2 AIR CONDITIONING CONTROL ASSEMBLY - IG POWER SOURCE)

(a) Disconnect the S90 No. 2 air conditioning control assembly connector.

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

Standard Voltage:

Tester Connection

Condition

Specified Condition

S90-2 (IG) - Body ground

Engine switch off

Below 1 V

S90-2 (IG) - Body ground

Engine switch on (IG)

11 to 14 V
NG

REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

2.

CHECK HARNESS AND CONNECTOR (NO. 2 AIR CONDITIONING CONTROL ASSEMBLY - BODY GROUND)

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

S90-4 (E) - Body ground

Always

Below 1 Ω
NG

REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

3.

CHECK HARNESS AND CONNECTOR (NO. 2 AIR CONDITIONING CONTROL ASSEMBLY - AIR CONDITIONING AMPLIFIER ASSEMBLY)

(a) Disconnect the J43 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

S90-6 (BLIN) - J43-16 (LIN3)

Always

Below 1 Ω

S90-6 (BLIN) or J43-16 (LIN3) - Other terminals and body ground

Always

10 kΩ or higher
NG

REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

4.

REPLACE NO. 2 AIR CONDITIONING HARNESS ASSEMBLY

(a) Replace the No. 2 air conditioning control assembly.

Click here

HINT:

Since the No. 2 air conditioning control assembly cannot be inspected while it is removed from the vehicle, replace the No. 2 air conditioning control assembly with a new or known good one and check that the condition returns to normal.

OK:

No. 2 air conditioning control assembly operation returns to normal.

Result

Proceed to

OK

A

NG (When troubleshooting according to Problem Symptoms Table)

B

NG (When troubleshooting according to the DTC)

C
A

END (NO. 2 AIR CONDITIONING CONTROL ASSEMBLY WAS DEFECTIVE)
B

PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE

C

REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY

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