Daimler Trucks
North America LLC

Field Service Campaign

September 2021
SF636A

Subject: Western Star 49X Differential Lock Parameter Update
Models Affected: Specific model year 2021-2022 Western Star 49X
vehicles, manufactured February 10, 2020, through March 15, 2021.

General Information
Daimler Trucks North America LLC (DTNA), on behalf of its wholly owned subsidiary Western Star Truck Sales,
Inc., is initiating Field Service Campaign SF636A to modify the vehicles mentioned above.
Vehicles may automatically disengage the differential lock without warning when vehicle speed reaches 25 mph.
The differential lock parameters will be updated to eliminate this automatic disengagement.
There are approximately 253 vehicles involved.
Additional Repairs
Dealers must complete all outstanding Recall and Field Service campaigns prior to the sale or delivery of a
vehicle. A Dealer will be liable for any progressive damage that results from its failure to complete campaigns
before sale or delivery of a vehicle.
Owners may be liable for any progressive damage that results from failure to complete campaigns within a
reasonable time after receiving notification.
Please contact Warranty Campaigns for consideration of additional charges prior to performing the repair.

Work Instructions
Please refer to the attached work instructions. Prior to performing the campaign, check the vehicle for a
completion sticker (Form WAR261).

Replacement Parts
This is a parameter update; no replacement parts required.

Removed Parts
U.S. and Canadian Dealers, please follow Warranty Failed Parts Tracking shipping instructions for the
disposition of all removed parts. Export distributors, please destroy removed parts unless otherwise advised.

Labor Allowance
Table 1 - Labor Allowance
Campaign
Number

Procedure

Time Allowed
(hours)

SRT Code

Corrective Action

SF636A

PARAMETER UPDATE, WST,
DIFFERENTIAL LOCK UPDATE

0.3

996-F030A

12-Repair Recall/Campaign

Table 1

IMPORTANT: When the campaign has been completed, locate the base completion label in the appropriate location on the vehicle, and attach the gray completion sticker provided in the field service kit (Form WAR261). If
the vehicle does not have a base completion label, clean a spot on the appropriate location of the vehicle and
first attach the base completion label (Form WAR259). If a field service kit is not required or there is no completion sticker in the kit, write the campaign number on a blank sticker and attach it to the base completion label.

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Daimler Trucks
North America LLC

Field Service Campaign

September 2021
SF636A

Claims for Credit
You will be reimbursed for your parts, labor, and handling (landed cost for Export Distributors) by submitting
your claim through the Warranty system within 30 days of completing this campaign. Please reference the
following information in OWL:
• Claim type is Field Service Campaign.
• In the Campaign field, enter the campaign number and appropriate condition code (SF636-A).
• In the Primary Failed Part field, enter 25-SF636-000.
• In the Parts section, there should be no entry unless due to special circumstances.
• In the Labor section, enter the appropriate SRT from the Labor Allowance Table. Administrative time will
be included automatically as SRT 939-6010A for 0.3 hours.
• The VMRS Component Code is F99-999-005 and the Cause Code is A1 - Campaign.
• This Field Service Campaign will terminate on September 30, 2022. Dealers will be notified of any
changes to the termination date via an Important Campaign Information Letter posted on DTNAConnect.
IMPORTANT: OWL must be viewed prior to beginning work to ensure the vehicle is involved and the campaign
has not previously been completed. Also, check for a completion sticker before beginning work.
All claims must be submitted within 30 days of the repair and within 30 days of the termination date of the
campaign. U.S. and Canadian Dealers: All excess inventory to be returned to the PDC following the conclusion
of the campaign must be returned in resaleable condition to the Memphis PDC within 90 days from the
termination date. Please submit a PAR to request return to the Memphis PDC. (Canadian dealers should return
the kits to their facing PDC.) Export Distributors: Excess inventory is not returnable.
For questions, U.S. and Canadian dealers, contact the Warranty Campaigns Department via Web inquiry at
DTNAConnect.com/WSC, or the Customer Assistance Center at (800) 385-4357, if you have any questions or
need additional information. Export distributors submit a Web inquiry or contact your International Service
Manager.

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Daimler Trucks
North America LLC

Field Service Campaign

September 2021
SF636A

Copy of Notice to Owners
Subject: Western Star 49X Differential Lock Parameter Update
Daimler Trucks North America LLC (DTNA), on behalf of its wholly owned subsidiary Western Star Truck Sales,
Inc., is initiating Field Service Campaign SF636A to modify specific model year 2021-2022 Western Star 49X
vehicles, manufactured February 10, 2020, through March 15, 2021.
Vehicles may automatically disengage the differential lock without warning when vehicle speed reaches 25 mph.
The differential lock parameters will be updated to eliminate this automatic disengagement.
Please contact an authorized DTNA dealer to arrange to have the campaign performed. To locate an authorized
dealer, go to Daimler-TrucksNorthAmerica.com/Contact-Us/. Scroll down to “Locate a Dealer,” and select the
appropriate brand. The campaign will take approximately one half hour and will be performed at no charge to
you.
This Field Service Campaign will terminate on September 30, 2022. Please make sure the campaign is
completed prior to this date. Work completed after this date will be done at the customer’s expense.
As stated in the terms of your express limited warranty, Daimler Trucks North America LLC will not pay for any
damage caused by failure to properly maintain your vehicle. Daimler Trucks North America LLC considers the
work necessary under this campaign to be proper maintenance and will, therefore, not pay for any damage to
your vehicle caused by your failure to have the repairs that are the subject of this campaign performed in a
reasonable time.
Contact the Warranty Campaigns Department at (800) 547-0712, from 7 a.m. to 4 p.m. Pacific Time, Monday
through Friday, e-mail address [email protected], or the Customer Assistance Center
at (800) 385-4357, if you have any questions or need additional information.

WARRANTY CAMPAIGNS DEPARTMENT
Enclosure

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Daimler Trucks
North America LLC

Field Service Campaign

September 2021
SF636A

Work Instructions
Subject: Western Star 49X Differential Lock Parameter Update
Models Affected: Specific model year 2021-2022 Western Star 49X
vehicles, manufactured February 10, 2020, through March 15, 2021

Differential Lock Parameter Update
1.

Check the base label (Form WAR259) for a completion sticker for SF636 (Form WAR261) indicating this
work has been done. The base label is usually located on the passenger door about 12 inches (30 cm)
below the door latch. If a sticker is present, no work is needed. If there is no sticker, proceed with the next
step.

2.

Park the vehicle on a level surface, shut down the engine, and set the parking brake. Chock the tires.

IMPORTANT: Make sure that DiagnosticLink® is updated to the latest version (8.14 SP3 at the time of publication, or newer) before programming the vehicle.
3.

Open DiagnosticLink prior to connecting to the vehicle.

4.

Using DTNAConnect credentials, connect DiagnosticLink to the server. The sign-in to the server will remain active until DiagnosticLink is closed. See Fig. 1.

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f120845

Fig. 1, Sign-In Window
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Daimler Trucks
North America LLC

Field Service Campaign

September 2021
SF636A
5.

Connect the vehicle to DiagnosticLink. Ensure the sSAM rollcalls, and is visible in the ‘Connections’ window. See Fig. 2.

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Fig. 2, sSAM Connected

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Daimler Trucks
North America LLC

Field Service Campaign

September 2021
SF636A

6.

Open the ‘Parameters’ tab, and allow the parameters to be read completely by DiagnosticLink, as indicated by the status bar at the bottom of the screen. See Fig. 3.

2
1

3

02/04/2021

f120839

1. Connections List
2. Parameters Tab

3. ‘Reading Parameters’ Progress Bar

Fig. 3, Connecting Default ECUs and Reading Vehicle Parameters in DiagnosticLink

7.

Go to ‘Program Device,’ and make sure that the vehicle identification number (VIN) information that appears is correct. If not, remove each VIN by selecting the ‘Remove’ button located at the far right-hand
side of that VIN. To remove all the VINs at once, select the ‘Remove All’ button at the bottom of the
screen. See Fig. 4.
If the VIN is not automatically detected, select ‘Add request,’ then enter the VIN. Select the electronic control unit (ECU) to be connected. See Fig. 5 and Fig. 6.

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Daimler Trucks
North America LLC

Field Service Campaign

September 2021
SF636A

1

2

07/13/2021

f121011

1. Remove Button

2. Remove All Button
Fig. 4, Removing VINs

1

08/04/2021

f121012

1. Add Request Button
Fig. 5, Add Request and Connected Unit Button

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Daimler Trucks
North America LLC

Field Service Campaign

September 2021
SF636A

07/13/2021

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Fig. 6, Manually Connecting to DiagnosticLink

8.

Select ‘Connected Unit.’ Make sure the VIN information populated in the center window is correct, then
select ‘Download data from server’ at the lower left-hand side of the screen. See Fig. 7.

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Fig. 7, Downloading Data from the Server

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Daimler Trucks
North America LLC

Field Service Campaign

September 2021
SF636A

NOTE: In some vehicles, the SSAM parameters PACS_DiffLk_MaxEngSpeed and PACS_DiffLk_RA_DissenggSpeed may have already been updated to what is shown in step 9.
9.

After the server data download is complete, go to the ‘Parameters’ tab, then set the two parameters of the
SSAM02T ECU as follows.
• Set PACS_DiffLk_MaxEngSpeed to A0284579658-001 PACS DiffLk MaxEngSpeed = 65534.
. 8
See Fig.

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Fig. 8, Setting Parameter PACS_DiffLk_MaxEngSpeed

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Daimler Trucks
North America LLC

Field Service Campaign

September 2021
SF636A

• Set PACS_DiffLk_RA_DissenggSpeed to A0284579758-001 PACS DiffLk RA DissenggSpeed =
65534. See Fig. 9.

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f121053

Fig. 9, Setting Parameter PACS_DiffLk_RA_DissenggSpeed

10.

Select the ‘Send’ button to write the parameter changes to the sSAM ECU in the vehicle.

11.

Once the parameter write is complete, go to the ‘Program Device’ tab and verify there is a pending upload.
• If there is a pending upload, select ‘Connect to Server’ to upload the parameter updates to the server.
• If there is no pending upload, go to the ‘Parameters’ tab, then select ‘Refresh.’ Verify the parameters
are set as shown in step 9. Go to ‘Program Device;’ there should now be a pending upload. Select
‘Connect to Server’ to upload the parameter updates to the server.

12.

Once the parameter updates are uploaded to the server, disconnect the vehicle from DiagnosticLink.

13.

Clean a spot on the base label (Form WAR259), write the campaign number, SF636, on a blank red
completion sticker (Form WAR260), and attach it to the base label, indicating this work has been completed.

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