Lexus NX: Air Outlet Damper Control Servo Motor Circuit (Rear) (B1449)
DESCRIPTION
The No. 2 air conditioning radiator damper servo sub-assembly sends pulse signals to inform the air conditioning amplifier assembly of the damper position. The air conditioning amplifier assembly activates the motor (normal or reverse) based on these signals to move the No. 2 air conditioning radiator damper servo sub-assembly to the appropriate position, which controls the rear air outlet switching.
| DTC No. | Detection Item | DTC Detection Condition | Trouble Area | Memory | Note |
|---|---|---|---|---|---|
| B1449 | Air Outlet Damper Control Servo Motor Circuit (Rear) | Rear air outlet damper position sensor value does not change even if air conditioning amplifier assembly operates No. 2 air conditioning radiator damper servo sub-assembly |
| Memorized (30 seconds 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:
When the auxiliary battery is disconnected or the air conditioning amplifier assembly is replaced, be sure to perform servo motor initialization.
Click here .gif)
HINT:
Confirm that no mechanical problem is present because this DTC can be output when either a damper link or damper is mechanically locked.
PROCEDURE
| 1. | CHECK FOR DTC |
(a) Clear the DTC.
Click here
(b) Check for DTC.
Click here
| Result | Proceed to |
|---|---|
| DTC B1449 is not output | A |
| DTC B1449 is output | B |
| DTC B1449 and B1497 are output | C |
| A | .gif) | USE SIMULATION METHOD TO CHECK |
| C | | GO TO DTC B1497 |
|
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| 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 mode 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 Outlet Servo Pulse (R) | No. 2 air conditioning radiator damper servo sub-assembly target pulse | Min.: 128 Max.: 383 | FACE: 264 (pulse) B/L: 245 (pulse) FOOT: 208 (pulse) Foot/DEF: 208 (pulse) SHUT: 166 (pulse) | - |
| Air Outlet Servo Actual Pls(R) | No. 2 air conditioning radiator damper servo sub-assembly actual pulse | Min.: 128 Max.: 383 | FACE: 264 (pulse) B/L: 245 (pulse) FOOT: 208 (pulse) Foot/DEF: 208 (pulse) SHUT: 166 (pulse) | - |
| Tester Display |
|---|
| Air Outlet Servo Pulse (R) |
| Air Outlet Servo Actual Pls(R) |
OK:
When the mode switch is operated, 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 |
|
| 3. | CHECK NO. 2 AIR CONDITIONING RADIATOR DAMPER SERVO SUB-ASSEMBLY |
(a) Replace the No. 2 air conditioning radiator damper servo sub-assembly.
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
(c) Check for DTCs.
Click here
| Result | Proceed to |
|---|---|
| DTC B1449 is not output | A |
| DTC B1449 is output | B |
| A | | END (NO. 2 AIR CONDITIONING RADIATOR DAMPER SERVO SUB-ASSEMBLY IS DEFECTIVE) |
|
| 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
(c) Check for DTCs.
Click here
| Result | Proceed to |
|---|---|
| DTC B1449 is not output | A |
| DTC B1449 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
(b) Check for DTC.
Click here
| Result | Proceed to |
|---|---|
| DTC B1449 is not output | A |
| DTC B1449 is output | B |
| A | | USE SIMULATION METHOD TO CHECK |
| B | | REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY |
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SEE MORE:
How To Proceed With Troubleshooting
PROCEDURE 1. VEHICLE BROUGHT TO WORKSHOP
NEXT 2. CONFIRM PROBLEM SYMPTOMS
NEXT 3. CUSTOMER PROBLEM ANALYSIS (a) Check if the vehicle has been jump started due to a discharged auxiliary battery. Result Proceed to The vehicle has ne
Installation
INSTALLATION CAUTION / NOTICE / HINT NOTICE:
Always use a new grommet and valve core when installing the tire pressure warning valve and transmitter.
Check that the washer and nut are not damaged, and replace them if necessary.
Make sure not to damage the urethane covered backside of the tire
