Mack TerraPro Trucks Recalled for ECU Software Issue

TerraPro Recall Issued Over ECU Software Problem

TerraPro Recall Affects 775 Mack trucks

Mack Trucks is recalling 775 TerraPro trucks from model years 2022 through 2027 after a software problem was found in the engine control unit, or ECU. According to the National Highway Traffic Safety Administration (NHTSA), the issue could allow the engine to start even when the transmission is not in Neutral.

NHTSA listed the recall under campaign number 26V139000. Mack assigned the recall number SC0492. The affected vehicles are TerraPro (TE) trucks equipped with a proprietary transmission and Vehicle ECU5. Production dates in the recall report run from January 11, 2021, through February 24, 2026.

Why the Recall Was Issued

The recall report says an incorrectly set ECU parameter may fail to confirm that the truck is in Neutral before allowing the engine to start. Because of that, the trucks do not meet the requirements of Federal Motor Vehicle Safety Standard No. 102, which covers transmission shift lever sequence, starter interlock, and transmission braking effect.

NHTSA said that if the engine starts while the transmission is in gear, the truck may move unexpectedly. That can increase the risk of a crash or injury.

The recall filing also states that no warning is expected before the problem occurs.

What the TerraPro Recall Means for Truck Drivers

For commercial truck drivers and fleets, this recall involves a basic safety function tied to vehicle startup. A truck that can start while still in gear creates a serious concern, especially in work areas where drivers may be getting in or out of the cab or starting the truck in tight spaces, yards, terminals, or job sites.

The recall documents do not list any reported crashes, injuries, field reports, or warranty claims tied to this issue. Even so, Mack’s filing says the condition raises the risk of a crash or injury if the starter is activated while the transmission is engaged.

Because the affected vehicles are medium- and heavy-duty trucks, the issue is directly relevant to trucking operations. Carriers, maintenance teams, and owner-operators with affected TerraPro trucks may want to confirm whether their vehicles are included and prepare for the software update through a dealer.

Manufacturer Remedy

Mack said dealers will correct the issue by updating the ECU software at no cost to owners. In the Part 573 report, the company said the vehicle ECU parameter will be updated to the proper value.

The report also states that a stop ship was issued on March 5, 2026. Mack said new programming was released to production, and vehicles built before the clean point were reprogrammed.

Dealer notification was scheduled for March 18, 2026. Owner notification letters are expected to be mailed beginning May 8, 2026. The recall report lists a phased owner notification period through May 11, 2026. Vehicle identification numbers tied to the recall became searchable on NHTSA.gov on March 18, 2026.

TerraPro Recall Timeline

According to Mack’s filing, the issue first came to light on February 10, 2026, when the company’s compliance team found a possible noncompliance during an audit. The next day, the Safety Office notified the quality and engineering teams for further review.

The matter was reviewed by Mack’s Product Safety Evaluation Committee on February 23, 2026, which recommended that it be escalated to the Product Safety Committee. On March 4, 2026, that committee determined that a noncompliance existed and decided to begin a recall.

TerraPro Owners Can Contact Mack for Assistance

Owners with questions about the recall can contact Mack customer service at 1-800-866-1177 and reference recall number SC0492. NHTSA also said owners can contact the Vehicle Safety Hotline at 1-888-327-4236.