WenmarOpen by Wenmar Pro

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.

The communication, as NHTSA indexes it (as of 2026-10-19)
TypeService bulletin
NHTSA id10221399
Published by NHTSA2022-09-26
Manufacturer's numberS2121000008RevC
Manufacturer's date2022-06-02
NHTSA componentSERVICE 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

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

Brakes, Lighting, Transmission and driveline

Trouble codes named

P0755, P0765, P0871

Vehicles listed
RAM 25002019, 2020, 2021, 2022
RAM 35002019, 2020, 2021, 2022

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

Recalls for the same vehicles and component
20243282024-06-06. Brakes
24V4150002024-06-06. SERVICE BRAKES, AIR:ANTILOCK:CONTROL UNIT/MODULE; ELECTRONIC STABILITY CONTROL (ESC):CONTROL MODULE
20226442022-11-10. Powertrain
22V8350002022-11-10. POWER TRAIN:AUTOMATIC TRANSMISSION
20221082022-03-11. Brakes
22V1400002022-03-10. ELECTRONIC STABILITY CONTROL (ESC); SERVICE BRAKES, HYDRAULIC:ANTILOCK/TRACTION CONTROL/ELECTRONIC LIMITED SLIP:CONTROL UNIT/MODULE
20200252020-01-24. Powertrain
20V0430002020-01-24. POWER TRAIN:AUTOMATIC TRANSMISSION
20194392019-08-29. Brakes
19V6350002019-08-29. SERVICE BRAKES, HYDRAULIC:FOUNDATION COMPONENTS:DISC:CALIPER

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
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.
21-039-262026-05-20. Service bulletin. 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
21-039-262026-05-13. Service bulletin. 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.A2026-03-18. Service bulletin. 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.
S25050000032025-12-17. Service bulletin. Diagnostic Trouble Code (DTC) C0050-00-Brake System Hydraulic Leak Set After Recent Repair.
S25160000012025-10-29. Service bulletin. Driveline Vibration. Prop Shaft Diagnostic Information.
21-041-252025-10-08. Service bulletin. 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.
1077752025-10-08. Warranty extension. ID-25-15 (XW1) Aisin K1 Clutch/ Input Shaft Assembly - Select 2022 RAM Trucks (D2/DD/DP)
1077742025-10-08. Warranty extension. D-25-18 (XW1) Aisin K1 Clutch/ Input Shaft Assembly - Select 2022 RAM Trucks (D2/DD/DP)