Lexus NX: Lost Communication with Front Panel LIN (B14B2)

Lexus NX Service Manual / Vehicle Interior / Heating / Air Conditioning / Air Conditioning System / Lost Communication with Front Panel LIN (B14B2)

DESCRIPTION

The air conditioning control assembly communicates with the air conditioning amplifier assembly through the LIN communication system.

If the LIN communication system malfunctions, the air conditioning amplifier assembly does not operate even if the air conditioning control assembly is operated.

DTC No.

Detection Item

DTC Detection Condition

Trouble Area

Memory

Note

B14B2

Lost Communication with Front Panel LIN

Lost communication with the air conditioning control assembly.

  • Harness or connector
  • LIN communication system
  • Air conditioning control assembly
  • Air conditioning amplifier assembly

Memorized (10 seconds or more)

-

HINT:

The air conditioning amplifier assembly stores the DTC of the respective malfunction if it 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.
  • When the auxiliary battery is disconnected or the air conditioning amplifier assembly is replaced, be sure to perform servo motor initialization.

    Click here

PROCEDURE

1.

CHECK HARNESS AND CONNECTOR (AIR CONDITIONING CONTROL ASSEMBLY - BATTERY AND BODY GROUND)

(a) Disconnect the air conditioning control assembly connector.

*a

Front view of wire harness connector

(to Air Conditioning Control Assembly)

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

Standard Voltage:

Tester Connection

Switch Condition

Specified Condition

I13-8 (IG+) - Body ground

Power switch off

Below 1 V

Power switch on (IG)

11 to 14 V

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

I13-14 (GND) - Body ground

Always

Below 1 Ω

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

OK

2.

CHECK HARNESS AND CONNECTOR (AIR CONDITIONING CONTROL ASSEMBLY - AIR CONDITIONING AMPLIFIER ASSEMBLY)

(a) Disconnect the I13 air conditioning control assembly connector.

(b) Disconnect the I50 air conditioning amplifier assembly connector.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

I13-6 (LIN1) - I50-37 (LIN1)

Always

Below 1 Ω

I13-6 (LIN1) or I50-37 (LIN1) - Body ground

Always

10 kΩ or higher

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

OK

3.

CHECK AIR CONDITIONING CONTROL ASSEMBLY

(a) Replace the air conditioning control assembly.

Click here

(b) Check the air conditioning control assembly operates normally.

HINT:

Since the air conditioning control assembly cannot be inspected while it is removed from the vehicle, replace the air conditioning control assembly with a new or known good one and check that the condition returns to normal.

OK:

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 (AIR CONDITIONING CONTROL ASSEMBLY IS DEFECTIVE)

B

PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE

C

REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY

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 Installation

INSTALLATION CAUTION / NOTICE / HINT HINT: Use the same procedure for the RH and LH sides. The procedure listed below is for the LH side. PROCEDURE 1. INSTALL REAR NO. 2 SPEAKER ASSEMBLY NOTICE: Do not touch the cone part of the speaker. (a) Attach the 3 claws to install the rear No. 2 speak

 Parts Location

PARTS LOCATION ILLUSTRATION *A w/ Blind Spot Monitor System - - *1 REAR TELEVISION CAMERA ASSEMBLY *2 BLIND SPOT MONITOR SENSOR LH *3 ENGINE ROOM RELAY BLOCK - ECU-B NO.4 FUSE *4 NO. 2 ENGINE ROOM RELAY BLOCK - ECU-B NO.5 FUSE - ECU-IG NO.6 FUSE ILLUSTRATION *A

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