Recall 25V622 affects 156 2025-2026 Mack Pioneer Pr (4) trucks for a trailer lighting control module defect. Repair is free at any franchised Mack dealer.
Mack is recalling 156 2025-2026 Pioneer Pr (4) trucks because an improperly manufactured body control module can keep trailer lights from illuminating while towing. Trailer tail lights and turn signals that stay dark reduce visibility to other drivers and increase crash risk; Mack dealers will complete the recall repair free of charge.
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What's wrong?
In NHTSA campaign 25V622, the trailer body input and output module on 2025-2026 Mack Pioneer Pr (4) trucks is the electronic control unit that helps the truck communicate with trailer lighting circuits. When a trailer is connected, that module sends and receives the signals that let the trailer lights illuminate with the truck's lighting commands. That matters most when other drivers need to see braking, turns, and marker lights.
On affected trucks, certain modules were built with a bent printed circuit board assembly at the supplier's facility. The printed circuit board is the flat board that carries the module's electronic circuits. When that board is bent, the module loses proper communication, and the trailer lights fail to illuminate while towing.
The warning sign is a pop-up message telling the driver that communication is lost with the trailer body input and output module. If that message appears while towing, the trailer lighting system needs dealer attention.
Who's affected?
Covers the 2025 and 2026 model years with the same lighting control module listed for both.
| 2025 Mack Pioneer Pr (4) | Lighting control module |
|---|---|
| 2026 Mack Pioneer Pr (4) | Lighting control module |
| Units affected | 156 |
| Field incidents | NHTSA has logged no field incidents to date. |
A matching year and model does not guarantee inclusion. Check your VIN to confirm whether your specific truck is included.
What's the safety risk?
Trailer tail lights and turn signals that fail to illuminate reduce visibility to other drivers and increase the risk of a crash. A pop-up message about lost communication with the trailer body input output module is a warning sign. Schedule the repair soon. Repair is free at any franchised Mack dealer.
What should I do?
- Check your VIN to confirm your 2025-2026 Mack Pioneer Pr (4) is included in this recall.
- Contact your nearest franchised Mack dealer to schedule the free trailer body input/output module replacement that fixes the trailer-light control failure.
- Bring the recall notice if Mack has mailed one. If not, reference recall number 25V622 when you call.
- Check the trailer tail lights and turn signals before towing until the repair is complete.
- Avoid towing when the trailer lights or turn signals do not illuminate correctly.
What happens at the repair
At the dealer, a Mack technician replaces the trailer body input/output module that controls trailer lighting signals. The replacement parts and labor are free under the recall. Mack used its general reimbursement plan on file for owners who paid out of pocket for this repair before the recall notice. Bring documentation for the related repair to the service desk, or contact Mack customer service to start the reimbursement claim.
| Reimbursement | Reimbursement available |
|---|
Timeline
| September 18, 2025 | NHTSA published the recall |
|---|---|
| September 25, 2025 | Dealer notification began |
| September 25, 2025 | Dealer notification ended |
| September 25, 2025 | VIN-searchable in NHTSA's database — Check your VIN to see whether this recall applies to your specific vehicle. |
| November 19, 2025 | Owner notification mailed |
Frequently asked questions
What is recall 25V622?
Recall 25V622 covers 156 2025-2026 Mack Pioneer Pr (4) vehicles with an improperly manufactured body control module that can keep trailer tail lights and turn signals from illuminating. Mack dealers will replace the trailer body input/output module for free.
What should I do if my 2025-2026 Mack Pioneer Pr (4) is on this recall?
Check your VIN to confirm your specific vehicle is included in recall 25V622. If it is, contact a franchised Mack dealer to schedule replacement of the trailer body input/output module. Reference Mack recall number SC0484 when you call.
Is the Mack recall repair free?
Yes. Federal recall law requires manufacturers to repair safety defects at no cost, and Mack will replace the trailer body input/output module free of charge at a franchised Mack dealer.
What is the safety risk in recall 25V622?
The risk is reduced visibility to other drivers while towing a trailer. If the trailer tail lights or turn signals do not illuminate as intended, other drivers have less warning of your position or turn, increasing crash risk under recall 25V622.
When were owners notified about this Mack recall?
Mack mailed owner letters on November 19, 2025. VINs became searchable for this recall on September 25, 2025. If you bought the vehicle used or missed the letter, check your VIN and reference recall number 25V622 with the dealer.
More information
| NHTSA campaign page | nhtsa.gov/vehicle-recalls/25V622000 |
|---|---|
| Mack customer service | 1-800-866-1177 |
| NHTSA recall # | 25V622 |
| NHTSA recall # (full) | 25V622000 |
Source documents
-
Download Quarterly Report (PDF) - Download Recall Investigation Document (PDF) (PDF)
- Download Owner Notice (PDF)
- Download Recall Report (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 →