Lexus NX: Air Mix Damper Control Servo Motor Circuit (Passenger Side) (B1441)

DESCRIPTION

The No. 1 air conditioning radiator damper servo sub-assembly (front passenger side air mix) sends pulse signals to indicate the damper position to the air conditioning amplifier assembly. The air conditioning amplifier assembly activates the motor (normal or reverse) based on these signals to move the No. 1 air conditioning radiator damper servo sub-assembly (front passenger side air mix) to the appropriate position. This adjusts the amount of air passing through the heater core after passing the evaporator and controls the temperature of the output air.

DTC No.	Detection Item	DTC Detection Condition	Trouble Area	Memory	Note
B1441	Air Mix Damper Control Servo Motor Circuit (Passenger Side)	Air mix damper position sensor value does not change even if air conditioning amplifier assembly operates No. 1 air conditioning radiator damper servo sub-assembly (front passenger side air mix)	No. 1 air conditioning radiator damper servo sub-assembly (front passenger side air mix) Air conditioning harness assembly Air conditioning amplifier assembly	Memorized (30 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

HINT:

Confirm that no mechanical problem is present because this diagnostic code can be output when either a damper link or the damper is mechanically locked.

PROCEDURE

1.	CHECK FOR DTC

(a) Clear the DTC.

Click here

Body Electrical > Air Conditioner > Clear DTCs

(b) Check for DTC.

Click here

Body Electrical > Air Conditioner > Trouble Codes

Result	Proceed to
DTC B1441 is not output	A
DTC B1441 is output	B
DTC B1441 and B1497 are output	C

A

USE SIMULATION METHOD TO CHECK

C

GO TO DTC B1497

B

2.	READ VALUE USING TECHSTREAM

(a) Connect the Techstream to the DLC3.

(b) Turn the power switch on (IG).

(c) Turn the Techstream on.

(d) Operate the front passenger side temperature adjustment switch.

(e) Enter the following menus: Body Electrical / Air Conditioner / Data List.

(f) Check the value(s) by referring to the table below.

Body Electrical > Air Conditioner > Data List

Tester Display	Measurement Item	Range	Normal Condition	Diagnostic Note
Air Mix Servo Targ Pulse(P)	No. 1 air conditioning radiator damper servo sub-assembly (front passenger side air mix) target pulse	Min.: 128 Max.: 383	MAX. COLD: 255 (pulse) MAX. HOT: 347 (pulse)	-
Air Mix Servo Actual Pulse(P)	No. 1 air conditioning radiator damper servo sub-assembly (front passenger side air mix) actual pulse	Min.: 128 Max.: 383	MAX. COLD: 255 (pulse) MAX. HOT: 347 (pulse)	-

Body Electrical > Air Conditioner > Data List

Tester Display
Air Mix Servo Targ Pulse(P)
Air Mix Servo Actual Pulse(P)

OK:

When the front passenger side temperature adjustment switch is turned from MAX COLD to MAX HOT, the actual pulse changes following the target pulse.

Result	Proceed to
Target pulse and actual pulse do not change	A
Target pulse changes but actual pulse does not change	B
Actual pulse changes following the target pulse (When troubleshooting according to the DTC)	C
Actual pulse changes following the target pulse (When troubleshooting according to Problem Symptoms Table)	D

A

REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY

C

GO TO STEP 5

D

PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE

B

3.	CHECK NO. 1 AIR CONDITIONING RADIATOR DAMPER SERVO SUB-ASSEMBLY (FRONT PASSENGER SIDE AIR MIX)

(a) Replace the No. 1 air conditioning radiator damper servo sub-assembly (front passenger side air mix).

Click here

HINT:

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

(b) Clear the DTC.

Click here

Body Electrical > Air Conditioner > Clear DTCs

(c) Check for DTC.

Click here

Body Electrical > Air Conditioner > Trouble Codes

Result	Proceed to
DTC B1441 is not output	A
DTC B1441 is output	B

A

END (NO. 1 AIR CONDITIONING RADIATOR DAMPER SERVO SUB-ASSEMBLY [FRONT PASSENGER SIDE AIR MIX] IS DEFECTIVE)

B

4.	CHECK AIR CONDITIONING HARNESS ASSEMBLY

(a) Replace the air conditioning harness assembly.

Click here

HINT:

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

(b) Clear the DTC.

Click here

Body Electrical > Air Conditioner > Clear DTCs

(c) Check for DTC.

Click here

Body Electrical > Air Conditioner > Trouble Codes

Result	Proceed to
DTC B1441 is not output	A
DTC B1441 is output	B

A

END (AIR CONDITIONING HARNESS ASSEMBLY IS DEFECTIVE)

B

REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY

5.	CHECK FOR DTC

(a) Clear the DTC.

Click here

Body Electrical > Air Conditioner > Clear DTCs

(b) Check for DTC.

Click here

Body Electrical > Air Conditioner > Trouble Codes

Result	Proceed to
DTC B1441 is not output	A
DTC B1441 is output	B

A

USE SIMULATION METHOD TO CHECK

B

REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY

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