# Service bulletin S2121000008RevC

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: 10221399
- Published by NHTSA: 2022\-09\-26
- Manufacturer's number: S2121000008RevC
- Manufacturer's date: 2022\-06\-02
- NHTSA component: SERVICE BRAKES; EXTERIOR LIGHTING; POWER TRAIN

## NHTSA's summary

Malfunction Indicator Lamp \(MIL\) Illumination. Diagnostic Trouble Codes \(DTCs\) P0765 ? UD Solenoid Circuit, P0871 ? Transmission Fluid Pressure Sensor/Switch ?C? Circuit Performance, and/or P0755 ? 2C Solenoid Circuit, Set.

## The document

- [NHTSA's copy of the document (PDF)](https://static.nhtsa.gov/odi/tsbs/2022/MC-10221399-0001.pdf)
- [If that address does not open, try this one](https://static.nhtsa.gov/odi/tsbs/2022/MC-10221399-9999.pdf)

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

## Components

Brakes, Lighting, Transmission and driveline

## Trouble codes named

P0755, P0765, P0871

## Vehicles listed

- 2019 to 2022 RAM 2500
- 2019 to 2022 RAM 3500

## Recalls for the same vehicles and component

- [2024328](/recalls/tc/2024328.md), 2024-06-06: Brakes
- [24V415000](/recalls/nhtsa/24V415000.md), 2024-06-06: SERVICE BRAKES, AIR:ANTILOCK:CONTROL UNIT/MODULE; ELECTRONIC STABILITY CONTROL \(ESC\):CONTROL MODULE
- [2022644](/recalls/tc/2022644.md), 2022-11-10: Powertrain
- [22V835000](/recalls/nhtsa/22V835000.md), 2022-11-10: POWER TRAIN:AUTOMATIC TRANSMISSION
- [2022108](/recalls/tc/2022108.md), 2022-03-11: Brakes
- [22V140000](/recalls/nhtsa/22V140000.md), 2022-03-10: ELECTRONIC STABILITY CONTROL \(ESC\); SERVICE BRAKES, HYDRAULIC:ANTILOCK/TRACTION CONTROL/ELECTRONIC LIMITED SLIP:CONTROL UNIT/MODULE
- [2020025](/recalls/tc/2020025.md), 2020-01-24: Powertrain
- [20V043000](/recalls/nhtsa/20V043000.md), 2020-01-24: POWER TRAIN:AUTOMATIC TRANSMISSION
- [2019439](/recalls/tc/2019439.md), 2019-08-29: Brakes
- [19V635000](/recalls/nhtsa/19V635000.md), 2019-08-29: SERVICE BRAKES, HYDRAULIC:FOUNDATION COMPONENTS:DISC:CALIPER

## Other bulletins for the same vehicles and component

- [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.
- [9100841](/bulletins/11034338.md), 2026-07-02, Service bulletin: POWER TRAIN. 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\-039\-26](/bulletins/11032827.md), 2026-05-20, Service bulletin: POWER TRAIN. Replace K1 Clutch / Input Shaft Assembly Customers must experience a Malfunction Indicator Lamp \(MIL\) illumination and the vehicle must exhibit/set the following Diagnostic Trouble Code \(DTC\): ● P0731\-00 \- Gear 1 Shift Incorrect Ratio \(This DTC will set during a key cycle and shifting into Drive\). Customers must also comment on the following: ● The transmission will not shift into or out of 1st \- 4th gears. 5th and reverse gears are still available This bulletin involves replacing the K1 clutch and possibly the K1 input shaft drum sub\-assembly. These repairs are to be performed only if the vehicle is inoperable due to K1 clutch failure
- [21\-039\-26](/bulletins/11032650.md), 2026-05-13, Service bulletin: POWER TRAIN. Replace K1 Clutch / Input Shaft Assembly Customers must experience a Malfunction Indicator Lamp \(MIL\) illumination and the vehicle must exhibit/set the following Diagnostic Trouble Code \(DTC\): ● P0731\-00 \- Gear 1 Shift Incorrect Ratio \(This DTC will set during a key cycle and shifting into Drive\). Customers must also comment on the following: ● The transmission will not shift into or out of 1st \- 4th gears. 5th and reverse gears are still available This bulletin involves replacing the K1 clutch and possibly the K1 input shaft drum sub\-assembly. These repairs are to be performed only if the vehicle is inoperable due to K1 clutch failure
- [S2621000003 REV.A](/bulletins/11030138.md), 2026-03-18, Service bulletin: POWER TRAIN. The vehicle will exhibit a service transmission/check engine warning indicator for the following transmission models: 845RE, 8HP45, 850RE, 8HP50, 8HP70, 8HP75, 8HP75\-PHEV, 8HP75\-LCV, 8HP90, 8HP95. Transmissions may exhibit the following diagnostic codes: P07E4, P1DB2, P0716, P1B14, P0733, P1D90, P1DB7, P1B13.
- [S2505000003](/bulletins/11026634.md), 2025-12-17, Service bulletin: SERVICE BRAKES. Diagnostic Trouble Code \(DTC\) C0050\-00\-Brake System Hydraulic Leak Set After Recent Repair.
- [S2516000001](/bulletins/11024577.md), 2025-10-29, Service bulletin: POWER TRAIN. Driveline Vibration. Prop Shaft Diagnostic Information.
- [21\-041\-25](/bulletins/11024061.md), 2025-10-08, Service bulletin: POWER TRAIN. Aisin K1 Clutch/Input Shaft Assembly Replacement XW1 Warranty Extension Customers must experience a Malfunction Indicator Lamp \(MIL\) illumination and the vehicle must exhibit/set the following Diagnostic Trouble Code \(DTC\): ● P0731\-00 \- Gear 1 Shift Incorrect Ratio. NOTE: This DTC will set during a key cycle and shifting into Drive. Customers may also comment on the following: ● The transmission will not shift into or out of 1st \- 4th gears. 5th and reverse gears are still available. This bulletin involves replacing the K1 clutch and possibly the K1 input shaft drum sub\-assembly.
- [107775](/bulletins/11024042.md), 2025-10-08, Warranty extension: POWER TRAIN. ID\-25\-15 \(XW1\) Aisin K1 Clutch/ Input Shaft Assembly \- Select 2022 RAM Trucks \(D2/DD/DP\)
- [107774](/bulletins/11024041.md), 2025-10-08, Warranty extension: POWER TRAIN. D\-25\-18 \(XW1\) Aisin K1 Clutch/ Input Shaft Assembly \- Select 2022 RAM Trucks \(D2/DD/DP\)

JSON: [/v1/bulletins/10221399](/v1/bulletins/10221399)

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