RAM
21-028-25 REV. C
Manufacturer communications
- Publication date
- 2025-10-18
- Received by NHTSA
- 2025-10-29
- NHTSA record numbers
- 11024601
Manufacturer summary
Original wording in English
Flash: Transmission Control Module (TCM) Updates Customers must experience a Malfunction Indicator Lamp (MIL) illumination and the vehicle must exhibit/set one or more of the following Diagnostic Trouble Codes (DTCs):
• P0827-00 - Up and Down Shift Switch Circuit Low.
• P0826-00 - Up and Down Shift Switch Circuit.
• P085F-00 - Up and Down Shift Switch Circuit Range/Performance.
• P1DCD-00 - TCM Monitoring Processor Performance Multiple Clutches Locked Up. Customers may also experience one or more of the following:
• Vehicle stuck in default gear, and possibly stranded for many minutes.
• Rough or bumpy 2-3 power on upshifts and/or 3-2 coast down shifts.
• Vehicle enters into limp home mode. Other software improvements:
• Decreased sensitivity to DTCs P1D8A and P1D8B This bulletin involves inspecting and possibly reprogramming the TCM with the latest available software.
• P0827-00 - Up and Down Shift Switch Circuit Low.
• P0826-00 - Up and Down Shift Switch Circuit.
• P085F-00 - Up and Down Shift Switch Circuit Range/Performance.
• P1DCD-00 - TCM Monitoring Processor Performance Multiple Clutches Locked Up. Customers may also experience one or more of the following:
• Vehicle stuck in default gear, and possibly stranded for many minutes.
• Rough or bumpy 2-3 power on upshifts and/or 3-2 coast down shifts.
• Vehicle enters into limp home mode. Other software improvements:
• Decreased sensitivity to DTCs P1D8A and P1D8B This bulletin involves inspecting and possibly reprogramming the TCM 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
P0826-00Up and Down Shift Switch CircuitRam
P0827-00Up and Down Shift Switch Circuit LowRam
P085F-00Up and Down Shift Switch Circuit Range/PerformanceRam
P1DCD-00TCM Monitoring Processor Performance Multiple Clutches Locked UpCheck 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 | 3500 | 2025 |