RAM
18-079-26
Manufacturer communications
- Publication date
- 2026-10-07
- Received by NHTSA
- 2026-10-16
- NHTSA record numbers
- 11038499 · 11038536
Multiple filings of the same bulletin are grouped here; original record numbers remain available.
Manufacturer summary
Original wording in English
Flash: Powertrain Control Module (PCM) Update Customers may experience a Malfunction Indicator Lamp (MIL) illumination, and the vehicle may exhibit SYMPTOM: or set one or more of the following Diagnostic Trouble Codes (DTCs):
• P0300-00 - Multiple Cylinder Misfire - in Active or Stored status set during cold start catalyst heating.
• P0301-00 - Cylinder 1 Misfire - in Active or Stored status set during cold start catalyst heating.
• P0302-00 - Cylinder 2 Misfire - in Active or Stored status set during cold start catalyst heating.
• P0303-00 - Cylinder 3 Misfire - in Active or Stored status set during cold start catalyst heating.
• P0304-00 - Cylinder 4 Misfire - in Active or Stored status set during cold start catalyst heating.
• P0305-00 - Cylinder 5 Misfire - in Active or Stored status set during cold start catalyst heating.
• P0306-00 - Cylinder 6 Misfire - in Active or Stored status set during cold start catalyst heating. Customers may also comment on one or more of the following:
• Vehicle has a rough idle.
• Engine has a miss.
• Noisy valvetrain. This bulletin involves inspecting the PCM software level and, if necessary, reprogramming the PCM with the latest available software.
• P0300-00 - Multiple Cylinder Misfire - in Active or Stored status set during cold start catalyst heating.
• P0301-00 - Cylinder 1 Misfire - in Active or Stored status set during cold start catalyst heating.
• P0302-00 - Cylinder 2 Misfire - in Active or Stored status set during cold start catalyst heating.
• P0303-00 - Cylinder 3 Misfire - in Active or Stored status set during cold start catalyst heating.
• P0304-00 - Cylinder 4 Misfire - in Active or Stored status set during cold start catalyst heating.
• P0305-00 - Cylinder 5 Misfire - in Active or Stored status set during cold start catalyst heating.
• P0306-00 - Cylinder 6 Misfire - in Active or Stored status set during cold start catalyst heating. Customers may also comment on one or more of the following:
• Vehicle has a rough idle.
• Engine has a miss.
• Noisy valvetrain. This bulletin involves inspecting the PCM software level and, if necessary, reprogramming the PCM with the latest available software.
Reported code forms
Manufacturer wording
Source wording can vary by vehicle and suffix. It is shown as written, not as a universal diagnosis.
Ram
P0300-00Multiple Cylinder Misfire - in Active or Stored status set during cold start catalyst heatingRam
P0301-00Cylinder 1 Misfire - in Active or Stored status set during cold start catalyst heatingRam
P0302-00Cylinder 2 Misfire - in Active or Stored status set during cold start catalyst heatingRam
P0303-00Cylinder 3 Misfire - in Active or Stored status set during cold start catalyst heatingRam
P0304-00Cylinder 4 Misfire - in Active or Stored status set during cold start catalyst heatingRam
P0305-00Cylinder 5 Misfire - in Active or Stored status set during cold start catalyst heatingRam
P0306-00Cylinder 6 Misfire - in Active or Stored status set during cold start catalyst heatingCheck vehicle applicability
A listed vehicle is a research lead. Confirm the engine, production range and software in the manufacturer's information.
| Make | Model | Model year |
|---|---|---|
| Ram | 1500 | 2025 |