TSB 2025 Ram 1500 Powertrain Control Module (PCM) Updates — 18-077-26

[RamRHOForum]

Technical Service Bulletin · TSB 18-077-26

This is a Technical Service Bulletin, not a recall. A TSB tells dealers how to diagnose and repair a specific symptom when a truck comes in with it. It doesn't mean every truck listed has the problem, and it doesn't by itself make the repair free -- coverage depends on your warranty and the dealer's diagnosis.

Published: Aug 19, 2026
Applies to: Ram 1500 (2025 model year)

Summary (official text)​

Flash: Powertrain Control Module (PCM) Updates Customers may experience a Malfunction Indicator Lamp (MIL) illumination and the vehicle may SYMPTOM: exhibit/set the following Diagnostic Trouble Code (DTC): ● P0300 - Multiple Cylinder Misfire. Customers may experience one of the following: ● Vehicle runs rough on initial cold start only after an overnight or extended soak. **This bulletin involves reprogramming the PCM with the latest available software.**

Sources​

• 18-077-26 (PDF, NHTSA document 11036359) — Aug 19, 2026

Details from NHTSA as of Oct 12, 2026. If NHTSA or Ram revises this notice, this post is updated and significant changes are noted in a reply. The linked documents are the authority, and a dealer can confirm whether it applies to your VIN.

Have you experienced this issue with your truck? Let us know your model year and engine, plus any diagnosis or repair details.