Four Zone Type
(Two Servo Module)

87106-50610

Damper Servo Sub-assy, Air
0–1
Conditioning Radiator, No. 5

Two Zone Type
(One Servo)

87106-50670

Damper Servo Sub-assy, Air
0–1
Conditioning Radiator, No. 5

Four Zone Type
(Two Servo Module)

0–1

Four Zone Type
(Two Servo Module)

Passenger Side FACE Servo
Motor Circuit / B1448
Air Outlet Damper FOOT/DEF
Control Servo Motor Circuit
(Passenger Side) / B1456
Air Outlet Rear FOOT Damper
Control Servo Motor Circuit
(Driver Side) / B148A
Air Outlet Rear FOOT Damper
Control Servo Motor Circuit
(Driver Side) / B148A
Air Outlet Rear FOOT Damper
Control Servo Motor Circuit
(Passenger Side) / B148B
Driver Side Air Outlet Damper
Control Servo Motor
Circuit / B1486
Air Outlet Damper Control
Servo Motor Circuit
(Passenger Side Front A/C
Rear Air Flow) / B1487

87020-50040

Damper Assy, Heater Air

© 2021 Lexus, a division of Toyota Motor Sales, USA

L-SB-0010-22

April 8, 2022

Page 7 of 17

HVAC Servo Motor Malfunction
Required Tools & Equipment
SPECIAL SERVICE TOOLS (SST)

PART NUMBER

QTY

Plastic Pry Tool Kit*

00002-06020-02

1

DCA-8000 Battery Diagnostic Tool*

DCA-8000P T

1

*Essential SST.

NOTE
Additional SSTs may be ordered by calling 1-800-933-8335.

REQUIRED TOOLS & MATERIAL

Supplier

PART NUMBER

Techstream ADVi*

TSADVUNIT

Techstream 2.0

TS2UNIT

QTY

1
Techstream Lite

ADE

TSLITEPDLR01

Techstream Lite (Green Cable)

TSLP2DLR01

Robinair R1234YF A/C Machine

ROB118150008

1

*Essential SST.

NOTE
 Only ONE of the Techstream units listed above is required.
 Software version 17.00.011 or later is required.
 Additional Techstream units may be ordered by calling Approved Dealer Equipment (ADE)
at 1-800-368-6787.

Calibration Information
CALIBRATION ID
MODEL

MODEL YEAR
PREVIOUS

NEW

8865F5001001
2018
LS 500, LS 500h

8865F5005001
8865F5002004

2019

8865F5002102

© 2021 Lexus, a division of Toyota Motor Sales, USA

8865F5006001

L-SB-0010-22

April 8, 2022

Page 8 of 17

HVAC Servo Motor Malfunction
Confirmation Procedure

1. Confirm the condition exists.
Does the vehicle exhibit one or more of the following conditions?


Uneven temperature or air flow between the vents.



Little or no air flow from the vent(s).



Improper MODE control function.



YES — Continue to the Flash Reprogramming Procedure section.



NO — Continue to step 2.

2. Using Techstream, check for the following stored DTCs:


B144A – Air Outlet DEF Damper Control Servo Motor Circuit



B1441 – Air Mix Damper Control Servo Motor Circuit (Passenger Side)



B1442 – Air Inlet Damper Control Servo Motor Circuit



B1443 – Air Outlet Damper Control Servo Motor Circuit



B1446 – Air Mix Damper Control Servo Motor Circuit (Driver Side)



B1448 – Passenger Side FACE Servo Motor Circuit



B1453 – Air Outlet Damper Cool Control Servo Motor Circuit (Driver Side)



B1454 – Air Outlet Damper Cool Control Servo Motor Circuit (Passenger Side)



B1455 – Air Outlet Damper FOOT/DEF Control Servo Motor Circuit (Driver Side)



B1456 – Air Outlet Damper FOOT/DEF Control Servo Motor Circuit (Passenger Side)



B1457 – Driver Side Air Outlet Damper Control Servo Motor Circuit



B1458 – Air Outlet Damper Control Servo Motor Circuit
(Passenger Side Front A/C Rear Air Flow)



B148A – Air Outlet Rear FOOT Damper Control Servo Motor Circuit (Driver Side)



B148B – Air Outlet Rear FOOT Damper Control Servo Motor Circuit (Passenger Side)



B1486 – Driver Side Air Outlet Damper Control Servo Motor Circuit



B1487 – Air Outlet Damper Control Servo Motor Circuit
(Passenger Side Front A/C Rear Air Flow)

Are ANY of the DTCs listed above present?


YES — Continue to the Flash Reprogramming Procedure section.



NO — This bulletin does NOT apply. Continue diagnosis using the applicable
Repair Manual.

© 2021 Lexus, a division of Toyota Motor Sales, USA

L-SB-0010-22

April 8, 2022

Page 9 of 17

HVAC Servo Motor Malfunction
Flash Reprogramming Procedure

1. Flash Reprogram the air conditioning amplifier assembly.
NOTE
The air conditioning amplifier flash reprogram is only performed one time if the air conditioning
amplifier has NOT been flash reprogrammed previously.

Follow the procedure outlined in L-SB-0001-18, Techstream ECU Flash Reprogramming
Procedure, and flash the air conditioning amplifier with the NEW calibration file update.
NOTICE
 Damage to the air conditioning amplifier may occur if the correct battery charge mode
setting is NOT used.
 Power Supply Mode is used to maintain battery voltage at 13.5V while
flash reprogramming.
 For details on how to use the battery diagnostic tool, refer to the
DCA-8000 Battery Diagnostic Tool Instruction Manual located in TIS – Diagnostics – Tools
& Equipment – Battery Diagnostics.

© 2021 Lexus, a division of Toyota Motor Sales, USA

L-SB-0010-22

April 8, 2022

Page 10 of 17

HVAC Servo Motor Malfunction
Servo Cleaning Procedure

1. Continue with the battery diagnostic tool connected using the “Power Supply Mode” ONLY.
2. Confirm flash reprograming of the air conditioning amplifier is complete.
3. BEFORE using the AC damper servo operation check tool, manually set the front and rear air
conditioning to the following settings:


MODE – Face



Temperature – Max Cold



Air Inlet – Recirculation

4. Select the following link to download the AC damper servo operation check tool
onto the Techstream desktop: AC damper servo operation check tool download.
5. Confirm the ignition is in the IG-ON position and the Techstream unit is connected to the
DLC3 connector.
6. Confirm NO other programs on the Techstream unit are currently communicating
with the vehicle.
7. Double-click on the AC damper servo operation check tool from the Techstream desktop.
8. Click on NEXT to start the AC damper
servo operation check tool and the
progress bar will show. It will take between
8 – 14 minutes to complete the cleaning
process depending on the condition of the
servos. The completion rate of the progress
bar will show between 50% – 100%.

Figure 1.

NOTE
If the connection between Techstream and
the vehicle is interrupted during the cleaning
process, the error message in Figure 1 will
also display. To reconnect, turn OFF the
Techstream unit and disconnect it from the
DLC3 connector, reconnect Techstream and
confirm connections, and turn ON the
Techstream unit and restart the
cleaning process.

© 2021 Lexus, a division of Toyota Motor Sales, USA

L-SB-0010-22

April 8, 2022

Page 11 of 17

HVAC Servo Motor Malfunction
Servo Cleaning Procedure (continued)

9. When the cleaning process is complete, the DTC check result screen shown below will be
displayed. If ANY DTC description is output, the servo related to it will require replacement.
Are ANY DTC descriptions output?


YES — Check the DTC description
and the Servo Location Guide,
and replace the appropriate
servo according to the
displayed DTC
description (Figure 2).



NO — Complete steps 10 – 11 to
complete the repair and return
the vehicle to the
customer (Figure 3).

Figure 2.

Figure 3.

© 2021 Lexus, a division of Toyota Motor Sales, USA

L-SB-0010-22

April 8, 2022

Page 12 of 17

HVAC Servo Motor Malfunction
Servo Cleaning Procedure (continued)

10. The Servo Cleaning Operation is complete. Turn OFF the ignition and click “EXIT.”
11. Turn OFF and disconnect the DCA-8000 battery diagnostic tool from the battery.

Servo Location Guide (Two and Four Zone HVAC Systems)

If there were any DTC descriptions output after step 9 in the Servo Cleaning Procedure, replace
the servos(s) per the replacement steps below for the appropriate servo requiring replacement.
Figure 4. Two Zone System
Air Conditioner (RH View)

Air Conditioner (LH View)

Blower (LH View)
9

6

3

7

2
4

8
5
1

SERVO
LOCATION

AC DAMPER OPERATION CHECK
TOOL DTC DESCRIPTION OUTPUT

1

Air Mix Servo Targ Pulse (D)

2

Cool A/M Servo Targ Pls (D)

3

A/O FACE Targ Pulse (D)

4

A/O FOOT/DEF Targ Pulse (D)

5

RELATED DTC(S)

SERVO PART NO.

B1446 / B1453

87106-11010

SERVO/MODULE
CONFIGURATION