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February 27, 2021 Service bulletin

Flash: Transmission Control Module (TCM) Updates

Ram technical service bulletin 2100921 for 2019 Ram 1500.

Bulletin number
2100921
Component
Exterior lighting
Summary
Flash: Transmission Control Module (TCM) Updates This bulletin involves reprogramming the TCM with the latest available software. Customers may experience a Malfunction Indicator Lamp (MIL) illumination. Upon further investigation the technician may find one or more of the following Diagnostic Trouble Codes (DTCs) have been set:P1DDE-00 - Ignition Run-Start Input 1-2 Correlation. P1DF3-00 - ECU Not Initialized. P07E4-00 - Unable To Engage Park. P0735-00 - Gear 5 Shift Incorrect Ratio. The customer may also notice the following condition: Drivetrain "clunks" or harsh/rough upshifts, specifically going into 2nd, 3rd or 4th gears. The following enhancements are also included in this software update:Improvement to the 5-3-2 downshift to preventDTC P0735-00. Shifter auto-position correction with ignition in the ?Run/Acc? positions during an AutoPark event.

Owners of these vehicles have filed 23 complaints in the lights category.

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