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21-027-25 REV. B

Manufacturer communications

Publication date
2025-10-18
Received by NHTSA
2025-10-29
NHTSA record numbers
11024600

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.

NHTSA manufacturer communications ↗

Reported code forms

Manufacturer wording

Source wording can vary by vehicle and suffix. It is shown as written, not as a universal diagnosis.

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MakeModelModel year
Ram25002025

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