21KWG – Work Brake May Unintentionally Disengage – 2019-2022 Kenworth T880, W990 Wrecker & Auto Hauler

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1/6/22, 2:11 PM Aftersales Service – Federal Recall Bulletin https://paccarnet.sharepoint.com/sitepages/wtyfedrecallbltndetail.aspx?ctx=eyJ3ZWJVcmwiOiJodHRwczovL3BhY2Nhcm5ldC5zaGFyZXBvaW50LmN… 1/5  Edit  Clone 21KWG / 21V906 / 2021-713 – Work Brake MayUnintentionally Disengage Number 21KWG / 21V906 / 2021-713 Supplier Kenworth Truck Company Description Recall 21KWG: Work Brake May Unintentionally Disengage Date 12/2/2021 What’s New Safety Recall – Work brake may unintentionally disengage. The work brake (also known as winch brake) mayunintentionally disengage during winching operations, releasing the service brakes, increasing the risk of crashor injury. The VECU software will be updated to correctly set the speed interlock parameter. Introduction The work brake, also known as winch brake, may unintentionally disengage during winching operations,releasing the service brakes. Slight vehicle movement during winching causes the wheel speed sensor to detect vehicle movement. There is“noise” in the wheel speed sensor at lower vehicle speeds, and erroneous values are communicated. Theseerroneous values exceed the speed interlock, causing the work brake to disengage. Situation 544 chassis (534 U.S. and 10 Canada) W990 and T880 chassis built from 08/22/2018 through 11/03/2021 andequipped with a work brake (winch brake) and intended service as a wrecker or auto hauler. Resolution Safety Recall Service all affected chassis 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 theirchassis is on the list. 1/6/22, 2:11 PM Aftersales Service – Federal Recall Bulletin https://paccarnet.sharepoint.com/sitepages/wtyfedrecallbltndetail.aspx?ctx=eyJ3ZWJVcmwiOiJodHRwczovL3BhY2Nhcm5ldC5zaGFyZXBvaW50LmN… 2/5 2. If you are not using Service Management to start repair orders, review SIR for “Complete” or “InProcess” next to the “21KWG” campaign code prior to performing this repair. 3. Follow the procedures below to update the VECU software and correctly set the speed interlockparameter. Federal Law It is a violation of Federal law for a dealer to sell or lease new vehicles covered by this recall until thedefect or noncompliance has been corrected. Warranty There is no time or mileage limit for this recall. Kenworth will pay for labor: 0.5 hours labor to update VECU software and CECU software for chassis with CVMUX electronicarchitecture. Includes accessing the parameter value via PVP to confirm the correct value. Use QuickClaim Code 21KWGA. 0.4 hours labor to update VECU software for chassis with VMUX electronic architecture. Includesaccessing the parameter value via PVP to confirm the correct value. Use Quick Claim Code 21KWGB. File an additional claim for extraordinary circumstances. A quick claim for standard labor must be filedfirst. File the claim within 14 days in accordance with Warranty Policy CA009 . Take-Off Parts Disposition: N/A 1/6/22, 2:11 PM Aftersales Service – Federal Recall Bulletin https://paccarnet.sharepoint.com/sitepages/wtyfedrecallbltndetail.aspx?ctx=eyJ3ZWJVcmwiOiJodHRwczovL3BhY2Nhcm5ldC5zaGFyZXBvaW50LmN… 3/5 PRWS CLAIM CODING CampaignCode: 21KWG CampaignType Safety Recall ClaimCategory: Truck Repair Type Proactive CustomerConcernCode 029 Causal Code A1 CorrectiveActionCode 12 ResponsibilityCode: Camp FailureLocation 003-001-088 Causal Part Q21-1126-700-700 SupplierCode N/A SRT Code 045-966 0.3 hrs. (VMUX Chassis)DAVIE4 –Download newsoftware to VECU. B45-967 0.4 hrs. (CVMUX Chassis)Update VECU andCECU software. B45-968 0.1 hrs. PVP processingand/or verification 1/6/22, 2:11 PM Aftersales Service – Federal Recall Bulletin https://paccarnet.sharepoint.com/sitepages/wtyfedrecallbltndetail.aspx?ctx=eyJ3ZWJVcmwiOiJodHRwczovL3BhY2Nhcm5ldC5zaGFyZXBvaW50LmN… 4/5 CLAIM CODING FailureLocation: 003-001-088 WorkAccomplished: 58 FailureType: 363 ResponsibilityCode: 01 SRTCode: 045-966 0.3 hrs. (VMUXChassis)DAVIE4 –Downloadnewsoftware toVECU. B45-967 0.4 hrs. (CVMUXChassis)UpdateVECU andCECUsoftware. B45-968 0.1 hrs. PVPprocessingand/orverification Claim Type: C Procedure Please follow your dealership’s safety procedures and precautions to ensure the vehiclecan be safely repaired and maintained. Go to PVP and verify the parameter (either N815 or AA01153) is set to 30MPH. Change to 30MPH if needed. 1/6/22, 2:11 PM Aftersales Service – Federal Recall Bulletin https://paccarnet.sharepoint.com/sitepages/wtyfedrecallbltndetail.aspx?ctx=eyJ3ZWJVcmwiOiJodHRwczovL3BhY2Nhcm5ldC5zaGFyZXBvaW50LmN… 5/5 Consult the chassis list to confirm the electrical architecture (VMUX or CVMUX) of thechassis. Refer to the appropriate procedure below. Update instructions for CVMUX chassis 1. Ensure DAVIE4 is up to date. 2. Connect a battery charger to the chassis. 3. Ensure all programs except DAVIE4 are closed when you begin programming. 4. Update the VECU software to the latest available version. 5. Ensure ESA is up to date. Refer to bulletin 03-064 for ESA best practices for software update instructionsand other tips. 6. Update the CECU software to the latest available version. Update instructions for VMUX chassis 1. Ensure DAVIE4 is up to date. 2. Connect a battery charger to the chassis. 3. Ensure all programs except DAVIE4 are closed when you begin programming. 4. Update the VECU software to the latest available version. Parts Parts are not required. Links U.S. Customer Letter Canada Customer Letter Chassis List Authored by: OF

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January 3, 2022 Subject: Safety Recall 21KWG – T800 and W990 Work Brake Functionality NHTSA Recall number 21V906 EXPIRATION DATE: NONE The VINs are listed on the back of this letter Dear Kenworth Customer, Kenworth Truck Company has decided that a defect which, relates to motor vehicle safety, exists in certain T880 and W990 vehicles built from 08/22/2018 through 11/03/2021 and equipped with a work brake (winch brake) and intended service as a wrecker or auto hauler. The work brake may unintentionally disengage during winching operations, releasing the service brakes and causing unintended vehicle movement, increasing the risk of a crash or injury. Kenworth has initiated a recall to remedy the defect free of charge. Please contact your Kenworth dealer. To find your Kenworth dealer, please visit Dealer Locator at www.Kenworth.com. This repair should take up to 1.0 hour labor depending on vehicle configuration Reciepts for parts and/or labor are required for consideration of reimbursement. This repair will be performed at no charge to you. The problem is… The work brake, also known as winch brake, may unintentionally disengage during winching operations, releasing the service brakes. What your dealer will do… Dealers will install a software update. What you must do … Contact your Kenworth Dealer to schedule an appointment for repair If you require further information about this campaign, reimbursement of a pre-notification remedy associated with this recall, or experience any difficulty in making arrangements for this repair, please contact Kenworth Customer Service, provide your name, your dealer’s city and state, your phone number, your email address (optional), the last 8 digits of your VIN, the bulletin number, and your question, using one of the following: Email: Kenworth.Campaigns@paccar.com with the bulletin number in the subject line or Mail: Kenworth Truck Company, P.O. Box 1000, Kirkland, WA 98083-1000, Attn: Customer Service Department or Phone: 425-828-5888 For additional information about the recall, you can contact Transport Canada at 1-800-333-0510. Federal regulation requires that any vehicle lessor receiving this campaign 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 of the new owner if you know their name. We regret any inconvenience that this work may cause you and appreciate your cooperation in this matter. Thank yo u, Annick Hollingsworth Director of Service Platforms Kenworth Truck Company

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OMB Control No.: 2127-0004 Part 573 Safety Recall Report 21V-906 The information contained in this report was submitted pursuant to 49 CFR §573 Manufacturer Name : PACCAR Incorporated Submission Date : NOV 19, 2021 NHTSA Recall No. : 21V-906 Manufacturer Recall No. : 21KWG and 21PBM Manufacturer Information : Manufacturer Name : PACCAR Incorporated Address : 777 106TH AVENUE NORTHEAST BELLEVUE WA 98004 Company phone : 940 591 4220 Population : Number of potentially involved : 908 Estimated percentage with defect : 100 % Vehicle Information : Vehicle 1 : 2019-2022 Kenworth and Peterbilt T880, W990, 536, 537, 567, 579, 389 Vehicle Type : BUSES, MEDIUM & HEAVY VEHICLES Body Style : OTHER Power Train : DIESEL Descriptive Information : Vehicles with certain software versions, a work or winch brake switch option, either a wrecker or auto hauler application, and a lower value for the work brake speed interlock parameter. Production Dates : AUG 22, 2018 – NOV 11, 2021 VIN Range 1 : Begin : 1NK1X4TX6KJ300654 End : 1NKZL40X3NJ124251 ✔ Not sequential Description of Defect : Description of the Defect : The work brake (also known as winch brake) may unintentionally disengage the service brakes during winching operations, causing the vehicle to roll. FMVSS 1 : NR FMVSS 2 : NR Description of the Safety Risk : If the work brake disengages, it may cause unintended vehicle movement. This may increase the risk of a crash and/or injury. Description of the Cause : Slight vehicle movement during winching causes the wheel speed sensor to detect vehicle movement. There is “noise” in the wheel speed sensor at lower vehicle speeds, and erroneous values are communicated. These erroneous values exceed the speed interlock, causing the work brake to disengage. Identification of Any Warning that can Occur : None. Involved Components : Part 573 Safety Recall Report 21V-906 Page 2 The information contained in this report was submitted pursuant to 49 CFR §573 Component Name 1 : Not Applicable Component Description : Not Applicable Component Part Number : Not Applicable Supplier Identification : Component Manufacturer Name : NR Address : NR NR Country : NR Chronology : 10-23-20: Driver reports hearing air exhaust and work brakes release during a winching operation, causing the vehicle to roll. No injuries or property damage was reported. Driver was able to manually apply brakes. Field service notified, engineering initiates investigation, and troubleshooting guidance is provided. 12-01-20: Field visits are completed with no issues identified, and unable to replicate customer complaint. All involved parts replaced as a precaution were reviewed with no issues identified. Investigation is placed in monitor status. 07-29-21: Dealership notifies Kenworth of customer reporting work brakes automatically disengaging on July 19. Investigation begins to understand details of recent event. 08-19-21: Technical team on-site at customer replicates complaint. Two trucks were used, one was winching the other truck. During the winching operation, the vehicle moved slightly, the team heard air exhaust, and the work brakes released. Upon further review, the wheel speed sensor noted there is “noise” in the sensor signal at speeds up to 7mph, and may be communicating an erroneous value. Certain vehicles are equipped with a work brake speed interlock, which causes the work brake to disengage at speeds above a set value. The team hypothesized that the “noise” in the sensor signal may be exceeding the speed interlock value, resulting in the work brakes disengaging. The investigation continued to evaluate this hypothesis further. 10-27-21: Team completes investigation and recommends increasing speed interlock value for all vehicles in wrecker applications. 11-10-21: The affected population is confirmed. 11-12-21: Production clean point for wrecker applications. 11-16-21: Safety committee meeting held. The committee agrees that a safety defect exists and that the affected population shall be recalled. 11-18-21: Production clean point for auto hauler applications. Part 573 Safety Recall Report 21V-906 Page 3 The information contained in this report was submitted pursuant to 49 CFR §573 Description of Remedy : Description of Remedy Program : Paccar will notify owners. Each suspect vehicle will have the speed interlock parameter value increased. This requires the vehicle software to be re-flashed to update the value. Owners who incurred costs to obtain a remedy for the problem addressed by the recall in advance of receiving notification may seek reimbursement through the process outlined in the general reimbursement plan on file. How Remedy Component Differs from Recalled Component : No physical components are affected. This is a software parameter update only. Any time the vehicle is connected to a Paccar service tool, the software version and parameters are compared with the back-office. Any parameter updates will inform the technician to complete a mandatory update. Identify How/When Recall Condition was Corrected in Production : The speed interlock parameter value was increased for all affected vehicles on 11/18/2021. Any vehicles which had already been built but were still on site at Paccar plants had the correct parameter value updated prior to being sold. Recall Schedule : Description of Recall Schedule : Owner notifications will be sent within 60 days. Planned Dealer Notification Date : JAN 18, 2022 – JAN 18, 2022 Planned Owner Notification Date : JAN 18, 2022 – JAN 18, 2022 * NR – Not Reported

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OMB Control No.: 2127-0004 Part 573 Safety Recall Report 21V-906 The information contained in this report was submitted pursuant to 49 CFR §573 Manufacturer Name : PACCAR Incorporated Submission Date : DEC 13, 2021 NHTSA Recall No. : 21V-906 Manufacturer Recall No. : 21KWG and 21PBM Manufacturer Information : Manufacturer Name : PACCAR Incorporated Address : 777 106TH AVENUE NORTHEAST BELLEVUE WA 98004 Company phone : 940 591 4220 Population : Number of potentially involved : 908 Estimated percentage with defect : 100 % Vehicle Information : Vehicle 1 : 2019-2022 Kenworth and Peterbilt T880, W990, 567, 579, 389 Vehicle Type : BUSES, MEDIUM & HEAVY VEHICLES Body Style : OTHER Power Train : DIESEL Descriptive Information : Vehicles with certain software versions, a work or winch brake switch option, either a wrecker or auto hauler application, and a lower value for the work brake speed interlock parameter. Production Dates : AUG 22, 2018 – NOV 11, 2021 VIN Range 1 : Begin : 1NK1X4TX6KJ300654 End : 1NKZL40X3NJ124251 ✔ Not sequential Vehicle 2 : 2022-2022 Peterbilt 536 Vehicle Type : Body Style : Power Train : NR Descriptive Information : ehicles with certain software versions, a work or winch brake switch option, either a wrecker or auto hauler application, and a lower value for the work brake speed interlock parameter. Production Dates : APR 08, 2021 – SEP 28, 2021 Description of Defect : Description of the Defect : The work brake (also known as winch brake) may unintentionally disengage the service brakes during winching operations, causing the vehicle to roll. FMVSS 1 : NR FMVSS 2 : NR Description of the Safety Risk : If the work brake disengages, it may cause unintended vehicle movement. This may increase the risk of a crash and/or injury. Part 573 Safety Recall Report 21V-906 Page 2 The information contained in this report was submitted pursuant to 49 CFR §573 Description of the Cause : Slight vehicle movement during winching causes the wheel speed sensor to detect vehicle movement. There is “noise” in the wheel speed sensor at lower vehicle speeds, and erroneous values are communicated. These erroneous values exceed the speed interlock, causing the work brake to disengage. Identification of Any Warning that can Occur : None. Involved Components : Component Name 1 : Not Applicable Component Description : Not Applicable Component Part Number : Not Applicable Supplier Identification : Component Manufacturer Name : NR Address : NR NR Country : NR Chronology : 10-23-20: Driver reports hearing air exhaust and work brakes release during a winching operation, causing the vehicle to roll. No injuries or property damage was reported. Driver was able to manually apply brakes. Field service notified, engineering initiates investigation, and troubleshooting guidance is provided. 12-01-20: Field visits are completed with no issues identified, and unable to replicate customer complaint. All involved parts replaced as a precaution were reviewed with no issues identified. Investigation is placed in monitor status. 07-29-21: Dealership notifies Kenworth of customer reporting work brakes automatically disengaging on July 19. Investigation begins to understand details of recent event. 08-19-21: Technical team on-site at customer replicates complaint. Two trucks were used, one was winching the other truck. During the winching operation, the vehicle moved slightly, the team heard air exhaust, and the work brakes released. Upon further review, the wheel speed sensor noted there is “noise” in the sensor signal at speeds up to 7mph, and may be communicating an erroneous value. Certain vehicles are equipped with a work brake speed interlock, which causes the work brake to disengage at speeds above a set value. The team hypothesized that the “noise” in the sensor signal may be exceeding the speed interlock value, resulting in the work brakes disengaging. The investigation continued to evaluate this hypothesis further. 10-27-21: Team completes investigation and recommends increasing speed interlock value for all vehicles in Part 573 Safety Recall Report 21V-906 Page 3 The information contained in this report was submitted pursuant to 49 CFR §573 wrecker applications. 11-10-21: The affected population is confirmed. 11-12-21: Production clean point for wrecker applications. 11-16-21: Safety committee meeting held. The committee agrees that a safety defect exists and that the affected population shall be recalled. 11-18-21: Production clean point for auto hauler applications. Description of Remedy : Description of Remedy Program : Paccar will notify owners. Each suspect vehicle will have the speed interlock parameter value increased. This requires the vehicle software to be re-flashed to update the value. Owners who incurred costs to obtain a remedy for the problem addressed by the recall in advance of receiving notification may seek reimbursement through the process outlined in the general reimbursement plan on file. How Remedy Component Differs from Recalled Component : No physical components are affected. This is a software parameter update only. Any time the vehicle is connected to a Paccar service tool, the software version and parameters are compared with the back-office. Any parameter updates will inform the technician to complete a mandatory update. Identify How/When Recall Condition was Corrected in Production : The speed interlock parameter value was increased for all affected vehicles on 11/18/2021. Any vehicles which had already been built but were still on site at Paccar plants had the correct parameter value updated prior to being sold. Recall Schedule : Description of Recall Schedule : Owner notifications will be sent within 60 days. Planned Dealer Notification Date : JAN 18, 2022 – JAN 18, 2022 Planned Owner Notification Date : JAN 18, 2022 – JAN 18, 2022 * NR – Not Reported

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OMB Control No.: 2127-0004 Part 573 Safety Recall Report 21V-906 The information contained in this report was submitted pursuant to 49 CFR §573 Manufacturer Name : PACCAR Incorporated Submission Date : DEC 09, 2021 NHTSA Recall No. : 21V-906 Manufacturer Recall No. : 21KWG and 21PBM Manufacturer Information : Manufacturer Name : PACCAR Incorporated Address : 777 106TH AVENUE NORTHEAST BELLEVUE WA 98004 Company phone : 940 591 4220 Population : Number of potentially involved : 908 Estimated percentage with defect : 100 % Vehicle Information : Vehicle 1 : 2019-2022 Kenworth and Peterbilt T880, W990, 567, 579, 389 Vehicle Type : BUSES, MEDIUM & HEAVY VEHICLES Body Style : OTHER Power Train : DIESEL Descriptive Information : Vehicles with certain software versions, a work or winch brake switch option, either a wrecker or auto hauler application, and a lower value for the work brake speed interlock parameter. Production Dates : AUG 22, 2018 – NOV 11, 2021 VIN Range 1 : Begin : 1NK1X4TX6KJ300654 End : 1NKZL40X3NJ124251 ✔ Not sequential Vehicle 2 : 2022-2022 Peterbilt 536 and 537 Vehicle Type : Body Style : Power Train : NR Descriptive Information : ehicles with certain software versions, a work or winch brake switch option, either a wrecker or auto hauler application, and a lower value for the work brake speed interlock parameter. Production Dates : APR 08, 2021 – SEP 28, 2021 Description of Defect : Description of the Defect : The work brake (also known as winch brake) may unintentionally disengage the service brakes during winching operations, causing the vehicle to roll. FMVSS 1 : NR FMVSS 2 : NR Description of the Safety Risk : If the work brake disengages, it may cause unintended vehicle movement. This may increase the risk of a crash and/or injury. Part 573 Safety Recall Report 21V-906 Page 2 The information contained in this report was submitted pursuant to 49 CFR §573 Description of the Cause : Slight vehicle movement during winching causes the wheel speed sensor to detect vehicle movement. There is “noise” in the wheel speed sensor at lower vehicle speeds, and erroneous values are communicated. These erroneous values exceed the speed interlock, causing the work brake to disengage. Identification of Any Warning that can Occur : None. Involved Components : Component Name 1 : Not Applicable Component Description : Not Applicable Component Part Number : Not Applicable Supplier Identification : Component Manufacturer Name : NR Address : NR NR Country : NR Chronology : 10-23-20: Driver reports hearing air exhaust and work brakes release during a winching operation, causing the vehicle to roll. No injuries or property damage was reported. Driver was able to manually apply brakes. Field service notified, engineering initiates investigation, and troubleshooting guidance is provided. 12-01-20: Field visits are completed with no issues identified, and unable to replicate customer complaint. All involved parts replaced as a precaution were reviewed with no issues identified. Investigation is placed in monitor status. 07-29-21: Dealership notifies Kenworth of customer reporting work brakes automatically disengaging on July 19. Investigation begins to understand details of recent event. 08-19-21: Technical team on-site at customer replicates complaint. Two trucks were used, one was winching the other truck. During the winching operation, the vehicle moved slightly, the team heard air exhaust, and the work brakes released. Upon further review, the wheel speed sensor noted there is “noise” in the sensor signal at speeds up to 7mph, and may be communicating an erroneous value. Certain vehicles are equipped with a work brake speed interlock, which causes the work brake to disengage at speeds above a set value. The team hypothesized that the “noise” in the sensor signal may be exceeding the speed interlock value, resulting in the work brakes disengaging. The investigation continued to evaluate this hypothesis further. 10-27-21: Team completes investigation and recommends increasing speed interlock value for all vehicles in Part 573 Safety Recall Report 21V-906 Page 3 The information contained in this report was submitted pursuant to 49 CFR §573 wrecker applications. 11-10-21: The affected population is confirmed. 11-12-21: Production clean point for wrecker applications. 11-16-21: Safety committee meeting held. The committee agrees that a safety defect exists and that the affected population shall be recalled. 11-18-21: Production clean point for auto hauler applications. Description of Remedy : Description of Remedy Program : Paccar will notify owners. Each suspect vehicle will have the speed interlock parameter value increased. This requires the vehicle software to be re-flashed to update the value. Owners who incurred costs to obtain a remedy for the problem addressed by the recall in advance of receiving notification may seek reimbursement through the process outlined in the general reimbursement plan on file. How Remedy Component Differs from Recalled Component : No physical components are affected. This is a software parameter update only. Any time the vehicle is connected to a Paccar service tool, the software version and parameters are compared with the back-office. Any parameter updates will inform the technician to complete a mandatory update. Identify How/When Recall Condition was Corrected in Production : The speed interlock parameter value was increased for all affected vehicles on 11/18/2021. Any vehicles which had already been built but were still on site at Paccar plants had the correct parameter value updated prior to being sold. Recall Schedule : Description of Recall Schedule : Owner notifications will be sent within 60 days. Planned Dealer Notification Date : JAN 18, 2022 – JAN 18, 2022 Planned Owner Notification Date : JAN 18, 2022 – JAN 18, 2022 * NR – Not Reported

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OMB Control No.: 2127-0004 Part 573 Safety Recall Report 21V-906 The information contained in this report was submitted pursuant to 49 CFR §573 Manufacturer Name : PACCAR Incorporated Submission Date : NOV 19, 2021 NHTSA Recall No. : 21V-906 Manufacturer Recall No. : 21KWG and 21PBM Manufacturer Information : Manufacturer Name : PACCAR Incorporated Address : 777 106TH AVENUE NORTHEAST BELLEVUE WA 98004 Company phone : 940 591 4220 Population : Number of potentially involved : 910 Estimated percentage with defect : 100 % Vehicle Information : Vehicle 1 : 2019-2022 Kenworth and Peterbilt T880, W990, 536, 537, 567, 579, 389 Vehicle Type : BUSES, MEDIUM & HEAVY VEHICLES Body Style : OTHER Power Train : DIESEL Descriptive Information : Vehicles with certain software versions, a work or winch brake switch option, either a wrecker or auto hauler application, and a lower value for the work brake speed interlock parameter. Production Dates : AUG 22, 2018 – NOV 11, 2021 VIN Range 1 : Begin : 1NK1X4TX6KJ300654 End : 1NKZL40X3NJ124251 ✔ Not sequential Description of Defect : Description of the Defect : The work brake (also known as winch brake) may unintentionally disengage the service brakes during winching operations, causing the vehicle to roll. FMVSS 1 : NR FMVSS 2 : NR Description of the Safety Risk : If the work brake disengages, it may cause unintended vehicle movement. This may increase the risk of a crash and/or injury. Description of the Cause : Slight vehicle movement during winching causes the wheel speed sensor to detect vehicle movement. There is “noise” in the wheel speed sensor at lower vehicle speeds, and erroneous values are communicated. These erroneous values exceed the speed interlock, causing the work brake to disengage. Identification of Any Warning that can Occur : None. Involved Components : Part 573 Safety Recall Report 21V-906 Page 2 The information contained in this report was submitted pursuant to 49 CFR §573 Component Name 1 : Not Applicable Component Description : Not Applicable Component Part Number : Not Applicable Supplier Identification : Component Manufacturer Name : NR Address : NR NR Country : NR Chronology : 10-23-20: Driver reports hearing air exhaust and work brakes release during a winching operation, causing the vehicle to roll. No injuries or property damage was reported. Driver was able to manually apply brakes. Field service notified, engineering initiates investigation, and troubleshooting guidance is provided. 12-01-20: Field visits are completed with no issues identified, and unable to replicate customer complaint. All involved parts replaced as a precaution were reviewed with no issues identified. Investigation is placed in monitor status. 07-29-21: Dealership notifies Kenworth of customer reporting work brakes automatically disengaging on July 19. Investigation begins to understand details of recent event. 08-19-21: Technical team on-site at customer replicates complaint. Two trucks were used, one was winching the other truck. During the winching operation, the vehicle moved slightly, the team heard air exhaust, and the work brakes released. Upon further review, the wheel speed sensor noted there is “noise” in the sensor signal at speeds up to 7mph, and may be communicating an erroneous value. Certain vehicles are equipped with a work brake speed interlock, which causes the work brake to disengage at speeds above a set value. The team hypothesized that the “noise” in the sensor signal may be exceeding the speed interlock value, resulting in the work brakes disengaging. The investigation continued to evaluate this hypothesis further. 10-27-21: Team completes investigation and recommends increasing speed interlock value for all vehicles in wrecker applications. 11-10-21: The affected population is confirmed. 11-12-21: Production clean point for wrecker applications. 11-16-21: Safety committee meeting held. The committee agrees that a safety defect exists and that the affected population shall be recalled. 11-18-21: Production clean point for auto hauler applications. Part 573 Safety Recall Report 21V-906 Page 3 The information contained in this report was submitted pursuant to 49 CFR §573 Description of Remedy : Description of Remedy Program : Paccar will notify owners. Each suspect vehicle will have the speed interlock parameter value increased. This requires the vehicle software to be re-flashed to update the value. Owners who incurred costs to obtain a remedy for the problem addressed by the recall in advance of receiving notification may seek reimbursement through the process outlined in the general reimbursement plan on file. How Remedy Component Differs from Recalled Component : No physical components are affected. This is a software parameter update only. Any time the vehicle is connected to a Paccar service tool, the software version and parameters are compared with the back-office. Any parameter updates will inform the technician to complete a mandatory update. Identify How/When Recall Condition was Corrected in Production : The speed interlock parameter value was increased for all affected vehicles on 11/18/2021. Any vehicles which had already been built but were still on site at Paccar plants had the correct parameter value updated prior to being sold. Recall Schedule : Description of Recall Schedule : Owner notifications will be sent within 60 days. Planned Dealer Notification Date : JAN 18, 2022 – JAN 18, 2022 Planned Owner Notification Date : JAN 18, 2022 – JAN 18, 2022 * NR – Not Reported

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