Recall 26V261 covers 2,337 2025-2027 Mack Pioneer Pr (4) and Anthem An (4) vehicles for rear-brake-modulator connector shorts. Free repair at franchised Mack dealers once available.
Mack is recalling 2,337 2025-2027 Pioneer Pr (4) and Anthem An (4) vehicles because unprotected rear brake modulator connectors can short circuit. A short can disable ABS and electronic stability control, increasing crash or injury risk; the Mack dealer repair will be free once available.
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What's wrong?
The rear brake modulator on the 2025-2027 Mack Pioneer Pr (4) and Anthem An (4) is part of the air-brake control system. It adjusts air pressure at the rear brakes so the anti-lock brake system and electronic stability control can help keep the truck stable during braking or a traction event.
On these trucks, Mack found that an electrical connector on the rear brake modulator was left without proper protection. Exposure during normal vehicle operation can let that connector short circuit. When that happens, the truck can lose ABS and ESC assistance, even though the foundation air brakes remain the main braking system.
There is no warning sign before failure. Do not count on a noise, smell, or brake-pedal change before the ABS and ESC fault appears.
Who's affected?
Covers Pioneer Pr (4) trucks from 2025-2027 and Anthem An (4) trucks from 2026-2027, all using the same anti-lock brake system (ABS) modulator.
| 2027 Mack Pioneer Pr (4) | anti-lock brake system (ABS) |
|---|---|
| 2026 Mack Pioneer Pr (4) | anti-lock brake system (ABS) |
| 2025 Mack Pioneer Pr (4) | anti-lock brake system (ABS) |
| 2027 Mack Anthem An (4) | anti-lock brake system (ABS) |
| 2026 Mack Anthem An (4) | anti-lock brake system (ABS) |
| Units affected | 2,337 |
| Field incidents | NHTSA has logged 5 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?
A loss of anti-lock brakes and electronic stability control reduces braking and stability support, increasing the risk of a crash or injury. There is no warning sign before the system stops working, so confirm your VIN and arrange service when the remedy opens. Repair will be free at any franchised Mack dealer once available.
What should I do?
- Check your VIN to confirm your 2025-2027 Mack Pioneer Pr (4) or Anthem An (4) is included in this recall.
- Watch for Mack's owner letter, scheduled for June 22, 2026, before scheduling the dealer repair.
- Contact a franchised Mack dealer after the owner letter arrives to schedule the free rear-brake-modulator connector inspection, protective cover installation, and modulator replacement that protects the ABS and ESC systems.
- Reference recall number 26V261 when you call the dealer or Mack customer service.
- Drive cautiously until the repair is complete. Leave extra following distance and avoid hard braking when traffic allows.
What happens at the repair
Once the repair opens, a Mack technician will inspect the rear brake modulator electrical connectors, install a protective cover, and replace rear brake modulators that need replacement. Parts and labor will be covered under the recall once available. Mack used its general reimbursement plan on file, so owners who already paid for the same rear brake modulator connector repair can ask Mack customer service about documented reimbursement under that standard plan. Keep prior repair invoices and payment records with your service paperwork.
| Reimbursement | Reimbursement available |
|---|
Timeline
| April 23, 2026 | NHTSA published the recall |
|---|---|
| April 30, 2026 | Dealer notification began |
| April 30, 2026 | Dealer notification ended |
| April 30, 2026 | VIN-searchable in NHTSA's database — Check your VIN to see whether this recall applies to your specific vehicle. |
Frequently asked questions
What is recall 26V261?
Recall 26V261 covers 2,337 2025-2027 Mack Pioneer Pr (4) and Anthem An (4) trucks with rear brake modulator electrical connectors that lack protection. The connectors can short circuit and cause loss of ABS and ESC. Mack dealers will inspect the connectors, install protective covers, and replace modulators when needed for free.
What should I do if my 2025-2027 Mack Pioneer Pr (4) or Anthem An (4) is on this recall?
Check your VIN to confirm your specific truck is included in recall 26V261. If it is, contact a franchised Mack dealer to schedule the inspection and repair once the recall work is available. Reference Mack recall number SC0494 when you call.
Is the recall repair free?
Yes. Federal recall law requires the manufacturer to repair the defect at no cost. Mack dealers will inspect the rear brake modulator electrical connectors, install protective covers, and replace the rear brake modulators when needed free of charge.
What is the safety risk in recall 26V261?
The safety risk is loss of anti-lock brakes and electronic stability control. Mack says the rear brake modulator electrical connectors can short circuit, which can disable ABS and ESC and increase crash or injury risk. The dealer repair addresses the exposed connector problem.
When will Mack notify owners about recall 26V261?
Mack expects to mail owner notification letters on June 22, 2026. VINs became searchable starting April 30, 2026. If your VIN is included before the letter arrives, call a franchised Mack dealer and reference recall number SC0494.
More information
| NHTSA campaign page | nhtsa.gov/vehicle-recalls/26V261000 |
|---|---|
| Mack customer service | 1-800-866-1177 |
| NHTSA recall # | 26V261 |
| NHTSA recall # (full) | 26V261000 |
This article is generated from NHTSA's primary recall filings and reviewed against the source on May 19, 2026. RecallNotify does not paraphrase NHTSA's consequence language; that text is reproduced as written above. Editorial standards →