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Service bulletins for the 2019 Ram 1500

A bulletin is a manufacturer's communication to its dealers, as NHTSA indexes it. The summary is NHTSA's. The document is the manufacturer's: read it at NHTSA. A bulletin is not a recall, and listing a model year does not mean every vehicle of it is concerned.

1178 on file from NHTSA, as of 2026-10-19.

About P1DDE on the 2019 Ram 1500: what the code means, and the bulletins and recalls about the same components.

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Only bulletins with trouble code: P1DDE are shown. Show all

Bulletins, newest first
21009212022-09-26. Service bulletin. POWER TRAIN; EXTERIOR LIGHTING; ELECTRICAL SYSTEM. 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.
21-009-212021-03-15. Service bulletin. POWER TRAIN. 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.
21-033-202020-05-26. Service bulletin. ELECTRICAL SYSTEM; POWER TRAIN. 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 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 following enhancement is included in this software update:Improvement to the 5-3-2 downshift to prevent DTC P0735-00. Shifter auto-position correction with ignition in RUN/ACC positions during an AutoPark event.
21-011-202020-04-06. Service bulletin. POWER TRAIN; ELECTRICAL SYSTEM:SOFTWARE. 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 DTCs have been set:P1DDE-00 - Ignition Run-Start Input 1-2 Correlation(Sales Code DFR Only). P1DF3-00 - ECU Not Initialized(Sales Code DFR Only). P0456 - EVAP System Small Leak. P0733-00 - Gear 3 Shift Incorrect Ratio (while operating in 4-Lo range). P0716-00 - Input Shaft Speed Sensor 1 Performance. P0721-00 - Output Shaft Speed Sensor Circuit Performance. P1DB6-00 - Vehicle Speed Signal Performance. P1DAB-00 - Vehicle Speed Undetermined. P215C-00 - Output Shaft Speed Wheel Speed Correlation. P0607-00 - ECU Internal Performance. P1DAC-00 - Engine Speed Undetermined. P07BF-00 - Input/Turbine Shaft Speed Sensor 1 Circuit Low. P07C0-00 - Input/Turbine Shaft Speed Sensor 1 Circuit High. P077C-00 - Output Shaft Speed Sensor Circuit Low. P077D-00 - Output Shaft Speed Sensor Circuit High. P177F-00 - Output Shaft Speed Sensor Out Of Range High. P1778-00 - Input-Turbine Shaft Speed Sensor A Out Of Range High. In addition, the following software enhancements are also available:Engine Stop/Start (ESS) Autostart improvements to adapt to Powertrain Control Module (PCM) and Hybrid Control Processor (HCP) changes. Coast-down downshift improvements for 4-3 on slight down hill and light braking. Low pedal kick-down bump improvement on 3-2 and 2-1 downshift. Improve 2-3 upshift at Wide Open Throttle (WOT) in tow/haul mode. Improve 5-6-5 gear hunt after cruise control resume acceleration. Cruise control improvement to help maintain speeds in tow/haul mode up hill. Improve 4-5 gear hunt in tow/haul up hill. Improve 7-8 gear hunt. Improve low speed upshift, stays in a lower gear to long. 1-2 coast-down shift improvements when coming to a stop. Shifter auto-position correction with ignition in RUN/ACC
21-009-202020-04-06. Service bulletin. POWER TRAIN; AIR BAGS; TRAILER HITCHES; WHEELS; EXTERIOR LIGHTING; BACK OVER PREVENTION; ELECTRICAL SYSTEM. Flash: Transmission Control Module (TCM) Updates This bulletin involves reprogramming the TCM with the latest available software. Some customers may experience a Malfunction Indicator Lamp (MIL) illumination. Upon further investigation the technician may find one or more of the following DTCs: P1DDE-00 - Ignition Run-Start Input 1-2 Correlation(Sales Code DFR Only). P1DF3-00 - ECU Not Initialized(Sales Code DFR Only). P0733-00 - Gear 3 Shift Incorrect Ratio (while operating in 4-Lo range). P0716-00 - Input Shaft Speed Sensor 1 Performance. P0721-00 - Output Shaft Speed Sensor Circuit Performance. P1DB6-00 - Vehicle Speed Signal Performance. P1DAB-00 - Vehicle Speed Undetermined. P215C-00 - Output Shaft Speed Wheel Speed Correlation. P0607-00 - ECU Internal Performance. P1DAC-00-Engine Speed Undetermined. P07BF-00 - Input/Turbine Shaft Speed Sensor 1 Circuit Low. P07C0-00 - Input/Turbine Shaft Speed Sensor 1 Circuit High. P077C-00 - Output Shaft Speed Sensor Circuit Low. P077D-00 - Output Shaft Speed Sensor Circuit High. P177F-00 - Output Shaft Speed Sensor Out Of Range High. P1778-00 - Input-Turbine Shaft Speed Sensor A Out Of Range High. P0731-00 - Gear 1 Shift Incorrect Ratio. P0979-00 - Shift Solenoid 3 Control Circuit Low. P1DCD-00-TCM Monitoring Processor Performance Multiple Clutches Locked Up. In addition, the following software enhancements are also available:Auto-start Improvements. Low speed coast down bump improvements. Tip in bump improvements. Bump during tow/haul high throttle acceleration. Gear hunting during cruise resume. Gear hunting during uphill trailer tow. Cruise control under-speed during uphill trailer tow. Gear hunting during highway speed operation. Hang in gear when driver desires earlier upshift/lower engine speed operation. Coast-down downshift improvements for 6-5, 5-4 and 4-3. Coast-down downshift improvements for 2-1. Cold temperature downshift improvements for 6-5 and 4-3. Cold temperature upshift improvements for 1-2, 2-3, 3-4

The summaries are NHTSA's. Each bulletin's page links NHTSA's copy of the manufacturer's document.