# P1D8A on the 2025 Ram 4500

The bulletins listed name this code in NHTSA's summary, or are about the same components. A bulletin or a recall listed here may apply to the model year. None of it is a diagnosis.

This code is specific to a manufacturer and is not described here.

## Bulletins for this model year that name P1D8A

- [11032327](https://open.wenmarpro.com/bulletins/11032327), 2026-05-06: 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
- [11027628](https://open.wenmarpro.com/bulletins/11027628), 2026-01-14: 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.
- [11023605](https://open.wenmarpro.com/bulletins/11023605), 2025-10-02: 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 \(DTCs\): ● 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. Customers may also experience one or more of the following: ● Vehicle stuck in default gear, and possibly stranded for many minutes. ● 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 faults P1D8A and P1D8B. This bulletin involves reprogramming the TCM with the latest available software.
- [11023325](https://open.wenmarpro.com/bulletins/11023325), 2025-09-24: 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 \(DTCs\): ● 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. Customers may also experience one or more of the following: ● Vehicle stuck in default gear, and possibly stranded for many minutes. ● 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 faults P1D8A and P1D8B. This bulletin involves reprogramming the TCM with the latest available software.