# Service bulletin 21\-005\-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.

- Type: Service bulletin
- NHTSA id: 11027631
- Published by NHTSA: 2026\-01\-14
- Manufacturer's number: 21\-005\-26
- Manufacturer's date: 2026\-01\-08
- NHTSA component: POWER TRAIN

## NHTSA's summary

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 reprogramming the TCM with the latest available software.

## The document

- [NHTSA's copy of the document (PDF)](https://static.nhtsa.gov/odi/tsbs/2026/MC-11027631-0001.pdf)
- [If that address does not open, try this one](https://static.nhtsa.gov/odi/tsbs/2026/MC-11027631-9999.pdf)

The document is the manufacturer's. This site does not hold it.

## Components

Transmission and driveline

## Trouble codes named

P0826, P0827, P085F, P1D8A, P1D8B

## Vehicles listed

- 2026 RAM 3500

## Other bulletins for the same vehicles and component

- [114739](/bulletins/11037595.md), 2026-09-30, Service bulletin: POWER TRAIN. TRANSMISSION KIT \- WITH TORQUE CONVERTER
- [08\-302\-26](/bulletins/11035977.md), 2026-08-06, Service bulletin: ELECTRICAL SYSTEM; POWER TRAIN. 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\-067\-26 REV. A](/bulletins/11035175.md), 2026-07-23, Service bulletin: POWER TRAIN. Flash: Powertrain Control Module \(PCM\) Updates Customers must experience a Malfunction Indicator Lamp \(MIL\) illumination and the vehicle must SYMPTOM: exhibit/set one or more of the following Diagnostic Trouble Codes \(DTCs\): ● P0088\-00 \- Fuel Rail Pressure Too High \- Bank 1. ● P208B\-00 \- Reductant Pump 1 Control Performance. This bulletin involves inspecting and possibly reprogramming the PCM with the latest available software.
- [S2523000088 REV.B](/bulletins/11035086.md), 2026-07-18, Service bulletin: ELECTRICAL SYSTEM; POWER TRAIN. Vehicle Shifter Will Not Shift Out Of Park.
- [18\-067\-26](/bulletins/11035055.md), 2026-07-18, Service bulletin: ENGINE; POWER TRAIN. Flash: Powertrain Control Module \(PCM\) Updates Customers must experience a Malfunction Indicator Lamp \(MIL\) illumination and the vehicle must SYMPTOM: exhibit/set one or more of the following Diagnostic Trouble Codes \(DTCs\): ● P0088\-00 \- Fuel Rail Pressure Too High \- Bank 1. ● P208B\-00 \- Reductant Pump 1 Control Performance. ● P2540\-00 \- Low Pressure Fuel System Sensor Circuit Range/Performance. ● P0506\-00 \- Idle Control System RPM \- Lower Than Expected. ● P20CF\-00 \- Exhaust Aftertreatment Fuel Injector "A" Stuck Open. ● P20DB\-00 \- Exhaust Aftertreatment Fuel Supply Control Stuck Open. ● P040B\-00 \- EGR Temperature Sensor 1 Circuit Performance. ● U0109\-00 \- Lost Communication With Fuel Pump Control Module. ● P1451\-00 \- Diesel Particulate Filter System Performance. ● P2463\-00 \- Diesel Particulate Filter Restriction \- Soot Accumulation Bank 1. ● P1191\-00\-Inlet Air Temperature Sensor Rational/Performance. ● P242F\-00\-Diesel Particulate Filter Restriction \- Ash Accumulation. ● P229F\-00 \- NOX Sensor Circuit Range/Performance \- Bank 1. ● P2281\-00 \- Air Leak Between MAF And Throttle Body. ● P0087\-00 \- Fuel Rail Pressure Too Low. ● P2540\-00 \- Low Pressure Fuel System Sensor Circuit Range/Performance. ● P2543\-00 \- Low Pressure Fuel System Sensor Circuit Intermittent. ● P214D\-00 \- SCR NOx Catalyst Outlet Temperature Too High During Particulate Filter Regeneration. ● P242B\-00 \- Exhaust Gas Temperature Sensor Circuit Performance \- Bank 1 Sensor 3. ● P24DA \- Particulate Matter Sensor Exhaust Sample Error Bank 1. ● P20EE\-00 \- SCR NOx Catalyst Efficiency Below Threshold \- Bank 1 Catalyst 1. ● P226C\-00 \- Turbocharger Boost Control "A" Slow Response. ● P2281\-00 \- Air Leak Between Maf And Throttle Body. ● P229F\-00 \- Nox Sensor Circuit Range/performance \- Bank 1. ● P0100\-00 \- Mass Or Volume Air Flow Sensor "A" Circuit. ● P203F\-00 \- Reductant Level Too Low. ● P0423\-00 \- Heated Catalyst Efficiency Below Threshold Bank 1. ● P06B9\-00 \- Cylinder 1 Glow Plug Circuit Performance. This bulletin involves inspecting and possibly reprogramming the PCM with the latest available software.
- [18\-025\-26 REV. B](/bulletins/11035053.md), 2026-07-18, Service bulletin: ELECTRICAL SYSTEM; POWER TRAIN. Flash: Powertrain Control Module \(PCM\) Updates Customers must experience a Malfunction Indicator Lamp \(MIL\) illumination and the vehicle must SYMPTOM: exhibit/set one or more of the following Diagnostic Trouble Codes \(DTCs\): ● P0088\-00 \- Fuel Rail Pressure Too High \- Bank 1. ● P208B\-00 \- Reductant Pump 1 Control Performance. ● P2540\-00 \- Low Pressure Fuel System Sensor Circuit Range/Performance. ● P0506\-00 \- Idle Control System RPM \- Lower Than Expected. ● P20CF\-00 \- Exhaust Aftertreatment Fuel Injector "A" Stuck Open. ● P20DB\-00 \- Exhaust Aftertreatment Fuel Supply Control Stuck Open. ● P040B\-00 \- EGR Temperature Sensor 1 Circuit Performance. ● U0109\-00 \- Lost Communication With Fuel Pump Control Module. ● P1451\-00 \- Diesel Particulate Filter System Performance. ● P2463\-00 \- Diesel Particulate Filter Restriction \- Soot Accumulation Bank 1. ● P1191\-00 \- Inlet Air Temperature Sensor Rational/Performance. ● P242F\-00 \- Diesel Particulate Filter Restriction \- Ash Accumulation. ● P229F\-00 \- NOX Sensor Circuit Range/Performance \- Bank 1. ● P2281\-00 \- Air Leak Between MAF And Throttle Body. ● P0087\-00 \- Fuel Rail Pressure Too Low. ● P2540\-00 \- Low Pressure Fuel System Sensor Circuit Range/Performance. ● P2543\-00 \- Low Pressure Fuel System Sensor Circuit Intermittent. ● P214D\-00 \- SCR NOx Catalyst Outlet Temperature Too High During Particulate Filter Regeneration. ● P242B\-00 \- Exhaust Gas Temperature Sensor Circuit Performance \- Bank 1 Sensor 3. ● P24DA \- Particulate Matter Sensor Exhaust Sample Error Bank 1. ● P20EE\-00 \- SCR NOx Catalyst Efficiency Below Threshold \- Bank 1 Catalyst 1. ● P226C\-00 \- Turbocharger Boost Control "A" Slow Response. ● P2281\-00 \- Air Leak Between Maf And Throttle Body. ● P229F\-00 \- Nox Sensor Circuit Range/performance \- Bank 1. ● P0100\-00 \- Mass Or Volume Air Flow Sensor "A" Circuit. ● P203F\-00 \- Reductant Level Too Low. ● P0423\-00 \- Heated Catalyst Efficiency Below Threshold Bank 1. ● P06B9\-00 \- Cylinder 1 Glow Plug Circuit Performance. This bulletin involves inspecting and possibly reprogramming the PCM with the latest available software.
- [18\-061\-26 REV. A](/bulletins/11034904.md), 2026-07-08, Service bulletin: POWER TRAIN. SA Market Only \- Flash: Powertrain Control Module \(PCM\) Updates Customers must experience a Malfunction Indicator Lamp \(MIL\) illumination and the vehicle must SYMPTOM: exhibit/set one or more of the following Diagnostic Trouble Codes \(DTCs\): ● \*\*P0088\-00 \- Fuel Rail Pressure Too High \- Bank 1.\*\* ● P0263\-00 \- Cylinder 1 Contribution/Balance. ● P0266\-00 \- Cylinder 2 Contribution/Balance. ● P0269\-00 \- Cylinder 3 Contribution/Balance. ● P0272\-00 \- Cylinder 4 Contribution/Balance. ● P0275\-00 \- Cylinder 5 Contribution/Balance. ● P0278\-00 \- Cylinder 6 Contribution/Balance. Customers may also comment one or more of the following: ● The engine runs rough and exhibits stumbling and shaking. ● Loss of power. NOTE: The perceived loss of power is due to an insufficient injector/torque response. This bulletin involves inspecting and possibly reprogramming the PCM with the latest available software.
- [S2523000055 REV.D](/bulletins/11034387.md), 2026-07-02, Service bulletin: POWER TRAIN; SERVICE BRAKES. Mil\-On/Check Engine Lamp \(CEL\), Antilock Brake System \(ABS\) Lamp, Diagnostic Trouble Code \(DTCs\).
- [9100841 Rev 1](/bulletins/11034380.md), 2026-07-02, Service bulletin: POWER TRAIN. 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.
- [18\-002\-26 REV. B](/bulletins/11034356.md), 2026-07-02, Service bulletin: POWER TRAIN; ELECTRICAL SYSTEM. Flash: Powertrain Control Module \(PCM\) Updates Customers may experience a Malfunction Indicator Lamp \(MIL\) illumination and the vehicle may exhibit/set one or more of the following Diagnostic Trouble Codes \(DTCs\): ● P219A \- Bank 1 Air\-Fuel Ratio Imbalance Bank 1. ● P219B \- Bank 2 Air\-fuel Ratio Imbalance. NOTE: This revision has an updated and more effective fix for DTC P219B than the prior version. Customers may also comment on one or more of the following: ● \*\*Power Take\-Off \(PTO\) may cancel during engagement with high PTO loads.\*\* ● PTO not auto\-resuming after hard\-wired remote start \(DD/DP Only\). ● Engine speed surging, unstable, 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 \(DD/DP Only\). In addition, the following software enhancement\(s\) is available: ● Increase the duration that Power Takeoff related messages are displayed on the Instrument Panel Cluster \(IPC\) \(DD/DP Only\) \*\*This bulletin involves inspecting and possibly reprogramming the PCM with the latest available software.\*\*

JSON: [/v1/bulletins/11027631](/v1/bulletins/11027631)

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