Recall 23V661 covers 254 2020-2024 Kenworth and Peterbilt trucks for delayed trailer-brake release. Dealers replace affected valve fittings and hoses free.
Kenworth recall 23V661 covers 254 2020-2024 T480, T380, T280, 536, 537, and 548 trucks because the trailer brake release timing is delayed. That delay can make the trailer unstable and increase crash risk, and Kenworth dealers will complete the repair free of charge.
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What's wrong?
The tractor protection valve is part of the air brake system on these 2020-2024 medium-duty trucks with optional end-of-frame trailer connections. It manages air supply between the tractor and trailer and helps protect the truck's air system if the trailer line loses pressure. In normal operation, the system releases the trailer brakes promptly when the driver releases the brake pedal.
On affected trucks, the end-of-frame trailer connection setup was not tested during the 2.1m Medium Duty product launch. The hose and fitting layout at the tractor protection valve, trailer modulator valve, and foot valve does not release the trailer brakes quickly enough. That delayed release means the trucks do not meet the federal air brake timing rule, FMVSS 121.
The warning sign is the trailer ABS malfunction light. If that light is illuminated, the electronic system that modulates the trailer brakes is unavailable to offset the 0.5 second release delay.
Who's affected?
Covers six Kenworth and Peterbilt medium-duty truck lines across the 2020-2024 model years; all share the same tractor protection valve.
| 2024 Kenworth T480 | brake system |
|---|---|
| 2024 Peterbilt 536 | brake system |
| 2021 Peterbilt 536 | brake system |
| 2021 Kenworth T380 | brake system |
| 2020 Peterbilt 548 | brake system |
| 2021 Peterbilt 548 | brake system |
| 2022 Peterbilt 536 | brake system |
| 2022 Peterbilt 548 | brake system |
| 2022 Kenworth T280 | brake system |
| 2022 Kenworth T480 | brake system |
| 2021 Kenworth T280 | brake system |
| 2021 Kenworth T480 | brake system |
| 2020 Peterbilt 536 | brake system |
| 2023 Kenworth T280 | brake system |
| 2023 Kenworth T380 | brake system |
| 2022 Kenworth T380 | brake system |
| 2023 Peterbilt 536 | brake system |
| 2023 Kenworth T480 | brake system |
| 2023 Peterbilt 548 | brake system |
| 2024 Kenworth T280 | brake system |
| 2024 Kenworth T380 | brake system |
| 2024 Peterbilt 537 | brake system |
| 2024 Peterbilt 548 | brake system |
| 2020 Kenworth T480 | brake system |
| Units affected | 254 |
| Field incidents | NHTSA has logged no field incidents to date. |
The year, make, and model narrow the scope, but the VIN decides. Check your VIN to confirm whether your specific truck is included.
What's the safety risk?
A delayed trailer brake release can make the trailer unstable and increase crash risk. If the trailer ABS malfunction light is on, the brake-modulation system is not available to offset the release delay. Treat that light as a reason to call the dealer before the next trailer trip. Repair is free at any franchised Kenworth dealer.
What should I do?
- Check your VIN to confirm your 2020-2024 Kenworth or Peterbilt truck is included in this recall.
- Contact a franchised Kenworth dealer to schedule the free repair.
- Schedule the air-brake valve fitting and hose replacement that fixes the delayed trailer brake release.
- Bring the recall notice if Kenworth has mailed one. If not, reference recall number 23V661 when you call.
- Drive cautiously until the repair is complete, especially when towing a trailer, because trailer brake release can be delayed.
What happens at the repair
At the dealer, a Kenworth technician replaces the fittings and hoses in the affected brake valves. The recall repair is free, with parts and labor covered. The work addresses delayed trailer brake release on the included trucks. PACCAR used its general reimbursement plan for this recall, so owners who already paid for the same valve, fitting, or hose repair can ask customer service how to submit documented expenses. Bring repair orders and payment records to the service desk.
| Reimbursement | Reimbursement available |
|---|
Timeline
| September 29, 2023 | NHTSA published the recall |
|---|---|
| November 20, 2023 | Dealer notification began |
| November 20, 2023 | Dealer notification ended |
| November 20, 2023 | VIN-searchable in NHTSA's database — Check your VIN to see whether this recall applies to your specific vehicle. |
| November 20, 2023 | Interim owner notification (was planned for this date) |
| January 15, 2024 | Owner notification mailed |
Frequently asked questions
What is recall 23V661?
Recall 23V661 covers 254 2020-2024 Kenworth trucks with air-brake valve fittings and hoses that can delay trailer brake release. That delay can make the trailer unstable and increase crash risk. Dealers will replace the fittings and hoses for free.
What should I do if my 2020-2024 Kenworth T480, 536, T380, 548, T280, or 537 is on this recall?
Check your VIN to confirm your specific truck is included in recall 23V661. If it is, contact a franchised Kenworth dealer to schedule the air-brake valve fitting and hose replacement. Reference recall number 23V661 and PACCAR recall number 23KWJ when you call.
Is the recall repair free?
Yes. Federal recall law requires the manufacturer to repair the defect at no cost, and PACCAR says dealers will replace the fittings and hoses in the affected valves free of charge. Parts and labor are covered at the dealer.
What is the safety risk?
The safety risk is trailer instability during brake release. PACCAR says delayed trailer brake release can create instability to the trailer and increase the risk of a crash. The dealer repair addresses that risk by replacing the fittings and hoses in the affected valves.
When were owners notified about recall 23V661?
PACCAR mailed owner letters on January 15, 2024. If you bought the truck used or never received a letter, the VIN still decides whether the recall applies. Check your VIN, then contact a franchised Kenworth dealer if your truck is included.
More information
| NHTSA campaign page | nhtsa.gov/vehicle-recalls/23V661000 |
|---|---|
| Kenworth customer service | 1-425-828-5888 |
| NHTSA recall # | 23V661 |
| NHTSA recall # (full) | 23V661000 |
Source documents
-
Download Quarterly Report (PDF) - Download Recall Report (PDF)
- Download Owner Notification Letter (PDF)
- Download Owner Notice (PDF)
- Download Recall Document (PDF) (PDF)
- Download Recall Document (PDF) (PDF)
- Download Recall Acknowledgement (PDF)
This article is generated from NHTSA's primary recall filings and reviewed against the source on May 20, 2026. RecallNotify does not paraphrase NHTSA's consequence language; that text is reproduced as written above. Editorial standards →