Technical Service Bulletin S4309 202412 — 2025 MACK GRANITE (GR)
ENGINE
Bulletin Details
| TSB ID | S4309 202412 |
| Manufacturer | |
| Vehicle | 2025 MACK GRANITE (GR) |
| Component | ENGINE |
| Communication Date |
Bulletin Summary
Mack Trucks has identified that certain GR model trucks may encounter an issue with the EECU during a shutdown event. If this occurs, the EECU could become corrupted, leading to multiple fault codes, engine derate, and, in some cases, preventing the truck from starting. For vehicles within the affected population, please follow the instructions below to program the EECU.
About Technical Service Bulletins
A Technical Service Bulletin (TSB) is a document issued by a vehicle manufacturer to its dealers, describing a known issue with a specific vehicle or set of vehicles and the recommended procedure to fix it. Unlike recalls, TSBs are not mandatory and are typically only performed if an owner reports the related issue. However, TSBs can be an indicator of common problems with a vehicle.