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Service bulletin 21-028-26

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.

The communication, as NHTSA indexes it (as of 2026-10-19)
TypeService bulletin
NHTSA id11031329
Published by NHTSA2026-04-15
Manufacturer's number21-028-26
Manufacturer's date2026-04-08
NHTSA componentPOWER TRAIN

NHTSA's summary

Flash: Transmission Control Module (TCM) Updates Customers must experience a Malfunction Indicator Lamp (MIL) illumination and the vehicle may SYMPTOM: exhibit/set one or more of the following Diagnostic Trouble Codes (DTCs): ? P0826-00 - Up/Down Shift Sw

The document

The document is the manufacturer's. This site does not hold it. NHTSA files a document at one of these two addresses; we have not asked NHTSA which.

Components

Transmission and driveline

Trouble codes named

P0826

Vehicles listed
RAM 25002025
RAM 35002025

Listing a model year does not mean every vehicle of it is concerned: the document says which.

Recalls for the same vehicles and component
20262252026-05-07. Powertrain
26V2880002026-05-07. POWER TRAIN:AUTOMATIC TRANSMISSION:CONTROL MODULE (TCM/PCM/TECM)
25V2970002025-05-08. ELECTRICAL SYSTEM: INSTRUMENT CLUSTER/PANEL; POWER TRAIN:AUTOMATIC TRANSMISSION:GEAR POSITION INDICATION (PRNDL)

A recall listed here may apply to some of the same vehicles. Only the manufacturer can say whether it applies to one vehicle.

Other bulletins for the same vehicles and component
1147392026-09-30. Service bulletin. TRANSMISSION KIT - WITH TORQUE CONVERTER
08-301-262026-08-06. Service bulletin. Flash: Electronic Shift Module (ESM) Updates Customers must experience a Malfunction Indicator Lamp (MIL) illumination and the vehicle must SYMPTOM: exhibit/set the following Diagnostic Trouble Code (DTC): ● U1057-00 - High Speed Fd-Can3 Communication Bus Performance. Customers may also comment on the following: ● If the vehicle has a low or drained battery and requires a jump start, once jump started, the vehicle will not shift out of Park. This bulletin involves reprogramming the ESM with the latest available software.
18-038-26 REV. A2026-08-06. Service bulletin. Flash: Powertrain Control Module (PCM) Updates Customers must experience a Malfunction Indicator Lamp (MIL) illumination and the vehicle exhibit/set SYMPTOM: one or more of the following Diagnostic Trouble Codes (DTCs): ● P219A - Bank 1 Air-Fuel Ratio Imbalance. ● P219B - Bank 2 Air-fuel Ratio Imbalance. ● P032F - Combustion Engine Producing Insufficient Torque. NOTE: This revision has an updated and more effective fix for DTC P219B than the prior version. Customers may experience one or more of the following: ● **Power Take Off (PTO) may cancel during engagement with high PTO loads.** ● Engine speed surging, unstable, hunting, or oscillating while coasting at low vehicle speeds. ● Stationary Idle PTO feature is not activating when the user configuration is selected to require parking brake be set (DD/DP Only). ● PTO not auto-resuming after hard-wired remote start (DD/DP Only). ● Driveline clunk or bump when coasting to a stop in cruise control mode. ● Engine idle undershoot or delayed response with power steering input. In addition, the following software enhancement(s) is available: ● Increase the duration that PTO related messages are displayed on the Instrument Panel Cluster (IPC) (DD/DP Only). This bulletin involves reprogramming the PCM with the latest available software.
S2523000088 REV.B2026-07-18. Service bulletin. Vehicle Shifter Will Not Shift Out Of Park.
18-066-262026-07-18. Service bulletin. Seed Request Denied During Technicians may experience the following: SYMPTOM: ● The scan tool displays the message "Seed Request denied" when attempting to reprogram the PCM to the latest available software.
S2523000055 REV.D2026-07-02. Service bulletin. Mil-On/Check Engine Lamp (CEL), Antilock Brake System (ABS) Lamp, Diagnostic Trouble Code (DTCs).
9100841 Rev 12026-07-02. Service bulletin. If customer concern diagnosis leads to suspect u-joint issue with the prop shaft, u-joint service kit should be utilized to fix concern. Prop shaft replacement would not be required.
91008412026-07-02. Service bulletin. HD Front and Rear Prop Shafts Increase U-Joint Usage If customer concern diagnosis leads to suspect u-joint issue or failure with the prop shaft, u-joint service kit should be utilized to fix concern. Prop shaft replacement would not be required.
21-028-26 REV. A2026-05-06. Service bulletin. Flash: Transmission Control Module (TCM) Updates Customers must experience a Malfunction Indicator Lamp (MIL) illumination and the vehicle may exhibit/set one or more of the following Diagnostic Trouble Codes (DTCs): ● P0826-00 - Up/Down Shift Switch. ● P0827-00 - Up/down Shift Switch Circuit Low. ● P085F-00 - Up And Down Shift Switch Circuit Range/performance. Customers may also experience one or more of the following: ● Customer is unable to switch the ignition to OFF when in Park gear. ● After shifting into Park, the Instrument Panel Cluster (IPC) will display that the transmission is in Neutral. NOTE: The transmission will actually be in Park and able to hold the vehicle, but the cluster display would indicate Neutral, preventing the engine from shutting off. ● Rough/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 if required reprogramming the TCM with the latest available software
S26090000052026-04-01. Service bulletin. Check Engine Light (CEL) Illuminated Diagnostic Trouble Code (DTC) P0381-00 Wait to Start Lamp Inoperative