12/8/25, 3:02 PM

Federal Recall Bulletin

Safety Recall 25PACF: EMUX Exterior Lighting Not
Compliant With FMVSS/CMVSS 108
Number

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25PACF / NHTSA # 25V436 / Transport Canada # 2025-357

Supplier
PACCAR

Description
EMUX Exterior Lighting Not Compliant With FMVSS/CMVSS 108

Date
7/25/2025

What’s New
Parts and procedures are now available for all affected chassis equipped with Vehicle Electronic Control
Unit (VECU) part number Q21-1157-013-011 / Q21-1157-013-013 / Q21-1157-002-002 / Q21-1157-004004 / Q21-1157-006-006 / Q21-1157-009-009. See attached Parts Matrix for required parts per chassis.

Introduction
Safety Recall
Parts and procedures are now available for all affected chassis equipped with Vehicle Electronic Control
Unit (VECU) part number Q21-1157-013-011 / Q21-1157-013-013 / Q21-1157-002-002 / Q21-1157-004004 / Q21-1157-006-006 / Q21-1157-009-009. See attached Parts Matrix for required parts per chassis.
Certain Ethernet Multiplexed Architecture (EMUX) chassis fail to conform to Federal and Canadian Motor
Vehicle Safety Standard (FMVSS/CMVSS) No. 108. Delayed or unsteady illumination of the vehicle’s
stop lamps, reverse lamps, turn signal lamps and inadvertent change in headlamp illumination or lift axle

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position may occur due to the Vehicle Electronic Control Unit (VECU) software configuration. This can
occur without warning and may increase the risk of a crash.

Situation
31,230 (29,039 US and 2,191 Canada) vehicle model year 2023-2026 Models 520 / 535 / 536 / 537 / 548
/ 567 / 579 / 589 built from 05/27/2022 through 05/23/2025 equipped with EMUX and VECU part number
Q21-1157.

Resolution
Safety Recall
Service all chassis affected that enter your dealership, even if the customer has no issue with the
chassis.
1. Review the attached chassis list for your dealer code and schedule your customer(s) for service if their
chassis is on the list.
2. In Service Management, select Campaign 25PACF to add it to the case. If the unit is released back
into service without performing the repair, make sure to also release the Campaign in Service
Management.
3. If you are not using Service Management to start repair orders, review SIR for “Complete” next to
the 25PACF Campaign code prior to performing this repair.
4. Follow the procedures to update the Digital Display (DD2), Central Security Gateway (CSG2), and
Vehicle Electronic Control Unit (VECU-3) software and, if necessary, replace modules as specified on the

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Parts Matrix.
NOTE
Software in all 3 modules
(DD2, CSG2, VECU-3) must
be updated.
Update software in the order
specified in the procedures.
Programming modules out of
order can cause programming
errors and may require
module replacement in order
to remedy the errors.

Federal Law
​It is a violation of Federal law for a dealer to sell or lease new vehicles covered by this recall until the defect or
noncompliance has been corrected.

Warranty
Starting on 07/25/2025, Peterbilt will pay for parts at dealer net plus applicable mark-up and labor:
0.5 hours (0.7 hours for Model 520) of labor to process a PVP file and program software only for
DD2, CSG2 and VECU-3 using DAVIE4. Use Recommended Repair Code 25PACFA starting on
07/25/2025.
For vehicles that require parts replacement, use editable Recommended Repair Code 25PACFB
detailing the parts replaced (from Parts Matrix) and software update. Use appropriate SRT codes

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(listed below) starting on 12/08/2025.
For supplemental repairs, file a long form claim and use code 25PACF in the Campaign Code field.
File the claim within 14 days in accordance with the Warranty Policy.

Take off parts disposition: Destroy 30 days after claim is paid
PRWS CLAIM CODING
Campaign 25PACF Campaign
Code:
Type

Safety Recall

Claim
Truck
Category:

Repair Type

Proactive

Customer 225
Concern
Code

Causal Code 93

Corrective 12
Action
Code

Responsibility Camp
Code:

Failure
Location

003Causal Part
006-003

Supplier
Code

N/A

SRT Code

Q21-1157013-013
B25-23A:
(HD & MD 0.5
hrs)
(520/L770 0.7
hrs)
Bulletin
25PACF:
Update
software for
CSG2, DD2,
VECU-3 and
perform repair
verification

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per bulletin
procedure
B25-23B:
(HD 0.3 hrs)
(MD 0.2 hrs)
Bulletin
25PACF: DD2
R&R Per
Bulletin
Procedure
B25-23C:
(0.2 hrs)
Bulletin
25PACF:
CSG2 R&R
Per Bulletin
Procedure
B25-23D:
(0.3 hrs)
Bulletin
25PACF:
VECU-3 R&R
Per Bulletin
Procedure
B25-23E:
(HD & MD 0.2
hrs)
(520/L770 0.5
hrs)
Bulletin
25PACF:
VCAN-2
Jumper
Harness
Installation
Per Bulletin
Procedure
B25-23F:
(HD/520/L770
0.2 hrs)
(MD 0.1 hrs)
Bulletin
25PACF:
Access to
CSG2,
VCAN-2
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Jumper
Harness and
VECU-3 (Can
be used once
per claim)

Procedure
Please follow your dealership's safety procedures and precautions to ensure the vehicle can be
safely repaired and maintained. Read all steps before beginning.
Note: Ensure DAVIE4 software version is the latest before completing this procedure.
For chassis listed as Phase 1 on the attached chassis list, follow the software update procedures below.
Hardware replacement is not required.
For chassis listed as Phase 2, refer to the attached Parts Matrix for chassis-specific replacement
requirements. Follow the appropriate attached procedures to replace and program VECU-3, DD2, and
CSG2 as necessary.

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NOTE
Software in all 3 modules
(DD2, CSG2, VECU-3) must
be updated.
Update software in the order
specified in the procedures.
Programming modules out of
order can cause programming
errors and may require
module replacement in order
to remedy the errors.

1. Process PACCAR Vehicle Pro (PVP) file.
In PACCAR.net open PACCAR Vehicle Pro (PVP).
Enter chassis number.
Select “Save and Continue.”
Select “Submit”.
2. Connect the 12V battery charger to the vehicle’s 12V battery.
3. Connect DAVIE4 tool.
Connect Nexiq to the 9-pin diagnostics connector.
Connect the Ethernet cable. See TIB 98-016 for Ethernet cable details.

NOTE: Do not connect the DAVIE4 Ethernet cable directly to the Digital Display (DD2). Doing so
bypasses the Central Security Gateway (CSG) and may cause a software update issue.

1. Ensure the PVP file is fully processed before moving on to the next steps.
2. Download required Digital Display (DD2), Central Security Gateway (CSG2) and Vehicle Electronic
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Control Unit (VECU3) software using DAVIE4.
Click “Identify Vehicle” on DAVIE4 Home Screen.

Under “Vehicle update” section, click on “Software”.

Retrieve software for DD2, CSG2 and VECU3.

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3. Upload required software for DD2, CSG2 and VECU3 modules following the prompts in DAVIE4
and in order listed below.
Update DD2 module
Update the CSG2 module.
Update VECU3 module.
4. Run “relearn switches” following DAVIE4 prompts.
5. Clear codes in all modules.
Refresh “Vehicle Check” to ensure there are no active fault codes.
6. Disconnect DAVIE4 and battery charger.

Parts
See attached Parts Matrix for parts required per chassis.
​Quantity

​ art
P
​Description
Number

​s
A
Needed ​Locally
​Cable Ties
(Up to
Sourced
15)

Links
PB Chassis List
PB Parts Matrix
PB HD Procedures
PB MD & 567 Car Hauler Procedures
PB Model 520 Procedures
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PB Customer Letter - US
PB Customer Letter - Canada
Authored by: JK / BDS

Revision History
12/08/2025: Parts and procedures are now available for all affected chassis.
08/19/2025: The procedure section has been updated with a note to inform technicians to not connect the
DAVIE4 Ethernet cable directly to the Digital Display (DD2). Doing so bypasses the Central Security
Gateway (CSG) and may cause a software update issue.

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IMPORTANT SAFETY RECALL
This notice applies to your vehicle. Your VIN(s) can be found on the bottom or back of this page.
Subject:

25PACF: EMUX Exterior Lighting Not Compliant With FMVSS 108
NHTSA: 25V436
EXPIRATION DATE: NONE

Dear Peterbilt Customer,
This notice is sent to you in accordance with the National Traffic and Motor Vehicle Safety Act.
Peterbilt Motors Company has decided that certain Vehicle Model Year 2023-2026 models 520 / 535 / 536 / 537 / 548 / 567 / 579 / 589 vehicles
manufactured between 05/27/2022 and 05/23/2025 equipped with Ethernet Multiplexed Architecture (EMUX) and Vehicle Electronic Control Unit
(VECU) part number Q21-1157 fail to conform to Federal Motor Vehicle Safety Standard (FMVSS) No.108, “Lamps, reflective devices, and
associated equipment.” Delayed or unsteady illumination of the vehicle’s stop lamps, reverse lamps, turn signal lamps, and inadvertent change in
headlamp illumination or lift axle position may occur due to the VECU software configuration. This can occur without warning and may increase the
risk of a crash. In addition, an unexpected position change of the lift axles may increase the risk of injury.
What is the problem?

Delayed or unsteady illumination of the vehicle’s stop lamps, reverse lamps, turn signal lamps and inadvertent
change in headlamp illumination or lift axle position.

What will your dealer do? Your Peterbilt dealer will update your vehicle’s software and replace parts as necessary.
What should you do?

Contact your Peterbilt Dealer immediately to schedule an appointment for repair.

Peterbilt has initiated this recall to remedy the issue at no charge to you. Please contact your Peterbilt dealer to schedule an appointment for these
services. To find your Peterbilt dealer, please visit the “Find a Dealer” link at www.Peterbilt.com or scan the QR code. When contacting your
Peterbilt dealer, reference the Safety Recall number, NHTSA Recall Number, and VIN(s) listed in this letter. This repair may take up to 2 hours of
labor depending on dealer scheduling.
If you had this repair performed before receiving this letter, you may be eligible to receive reimbursement for the cost of obtaining a pre-notification
remedy of the problem associated with this recall. Receipts for parts and/or labor are required for consideration of reimbursement. Contact your local
Peterbilt dealership for details.
If you require further information about this recall or experience any difficulty in making arrangements for this repair, please contact the Peterbilt
Customer Experience Department at PB.Tech.Pubs.Dept@paccar.com.
If you conclude that Peterbilt has not enabled you to remedy this defect in a reasonable time and without charge, you may submit a complaint to:
Administrator, National Highway Traffic Safety Administration, 1200 New Jersey Avenue, S.E., Washington, DC 20590, or call the toll-free Vehicle
Safety Hotline at 1-888-327-4236 (TTY: 1-800-424-9153); or go to http://www.safercar.gov.
Federal regulation requires that any vehicle lessor receiving this recall notice must forward a copy of this notice to the lessee within ten days. If you
no longer own this vehicle, we would appreciate your advising us about the new owner. Please send all known ownership and address changes to
PBDiv.Warranty.Docs@paccar.com.
We apologize for any inconvenience this procedure may cause and thank you for your participation in helping Peterbilt provide the highest levels of
customer satisfaction and service expertise. We value your business and appreciate your ongoing loyalty to Peterbilt and its dealer network. Industryleading quality, performance and reliability are hallmarks of Peterbilt products, and we thank you for making Peterbilt your truck of choice.
Sincerely,
Peterbilt Customer Experience