Service bulletin S2121000010

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)
Type	Service bulletin
NHTSA id	10198392
Published by NHTSA	2021-06-28
Manufacturer's number	S2121000010
Manufacturer's date	2021-05-28
NHTSA component	SUSPENSION

NHTSA's summary

Service 4WD Lamp On, 4WD System Does Not Work, 4WD Service Lamp Flashing, Front Axle Disconnect Does Not Engage Or Disengage

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

Suspension

Vehicles listed
RAM 2500	2019, 2020, 2021
RAM 3500	2019, 2020, 2021
RAM 4500	2019, 2020, 2021

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

Recalls for the same vehicles and component
21V016000	2021-01-20. SERVICE BRAKES; SERVICE BRAKES, HYDRAULIC:FOUNDATION COMPONENTS:HOSES, LINES/PIPING, AND FITTINGS; SUSPENSION:REAR

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
02-002-25 REV. A	2025-09-17. Service bulletin. Shock And Strut Diagnosis And Replacement Guidelines Leaking, noisy, or weak shocks or struts.
02-002-25	2025-05-30. Service bulletin. "Shock And Strut Diagnosis And Replacement Guidelines Leaking, noisy, or weak shocks or struts. "
9100229	2023-10-30. Service bulletin. LIFTER, Hydraulic Roller Deactivating Please do not replace MDS lifters because the disconnecting pin is not lined up, this is normal and not a defect.
9004383	2022-10-17. Service bulletin. TORSION ROD, Storage Bin (Rambox) If the Rambox storage bin Torsion Rods are being replaced for the lid not opening issue, replace the complete Rambox Bin and Lid assembly with all of the sub components instead of just replacing the Torsion Rods only. Please ship the complete Rambox Bin and Lid assembly without dis-assembling the lid or hinges to QEC. Please contact FCA Redacted Content to set up the part return to QEC. If no response in 15 minutes, proceed with repair.
0807320	2022-09-26. Service bulletin. Flash: Air Suspension Control Module (ASCM) Updates This bulletin involves reprogramming the ASCM with the latest available software. Customers may experience a Malfunction Indicator Lamp (MIL) illumination. Upon further investigation the technician may find that one or moreof the following DTCs have been set: U0132 - Loss of Communication with Air Suspension Control Module. C15E1-97 - Left Rear Air Spring Intake - Component or System Operation Obstructedor Blocked. C220C-48 - Active Suspension Module Internal-Supervision Software Failure(2019 MY Only). C211B-92 - Ignition Run/Start Input-Performance Or Incorrect Operation(2019 MY Only). C156C-7A - Ride Height System Air Leak-Fluid Leak Or Seal Failure(2019 MY Only). In addition the customer may describe: Air spring deflated or ruptured. Right/left rear suspensions sits lower than the other side. During key ?On? or while driving, the ?service air suspension?light illuminates. Chime and "Service Air Suspension Immediately" message appeared in the clusterfor 5 seconds. Air suspension system is inoperable. Excessive operation or noise from air suspension system when vehicle is stationary(2019 MY Only). "Air Suspension Disabled" message when attempting Bed Lowering Mode (BLM)(2019 MY Only). Excessive compressor valve cycling following a cold start(2019 MY with Diesel engine only). Erroneous "Bed Low Achieved" message through the Instrument Panel Cluster (IPC), when requesting lowering, even though the truck didn'tphysically lower. Ride height changes/valve actuations without operator request on rough roads.
S1917000002	2022-09-26. Service bulletin. ASCM U0132 Loss Of Communication With Suspension Control Module (IPC) DTC
9004407-1	2022-09-15. Service bulletin. COMPRESSOR ASSEMBLY, Air Suspension, Module ASCM replacement is rarely necessary. If the DTC is stored and able to be cleared, component replacement is not necessary. Please follow the service procedures to attempt to clear any active fault(s) which includes module hard reset, full CAN power down/sleep, or DTC clear in WiTech. Please contact FCA Redacted Content prior to any ASCM replacement at FCA Redacted Content If no response within 15 minutes, please proceed with repair. Any new module requires a flash following installation regardless of whether the current part number is up-to-date .
02-003-21	2022-08-22. Service bulletin. Noise in Front Over Bumps This bulletin involves checking the front shock absorbers Julian date (build date) and replacing if required. The customer may describe the following:Clunk in front suspension when driving over pot holes.
75745	2022-05-31. Service bulletin. HUB AND BEARING - WHEEL
08-175-21	2021-12-13. Service bulletin. Flash: Air Suspension Control Module (ASCM) Updates This bulletin involves reprogramming the ASCM with the latest available software. Customers may experience a Malfunction Indicator Lamp (MIL) illumination. Upon further investigation the technician may find that one or more of the following DTCs have been set:U0132 - Loss of Communication with Air Suspension Control Module. C15E1-97 - Left Rear Air Spring Intake - Component or System Operation Obstructed or Blocked. C220C-48 - Active Suspension Module Internal-Supervision Software Failure(2019 MY Only). C211B-92 - Ignition Run/Start Input-Performance Or Incorrect Operation(2019 MY Only). C156C-7A - Ride Height System Air Leak-Fluid Leak Or Seal Failure(2019 MY Only). In addition the customer may describe:Air suspension system is inoperable. During key ?On? or while driving, the ?service air suspension? light illuminates. Air spring deflated or ruptured. Right/left rear suspensions sits lower than the other side. Chime and "Service Air Suspension Immediately" message appeared in the cluster for 5 seconds. Excessive operation or noise from air suspension system when vehicle is stationary(2019 MY Only). "Air Suspension Disabled" message when attempting Bed Lowering Mode (BLM)(2019 MY Only). Excessive compressor valve cycling following a cold start(2019 MY with Diesel engine only). Erroneous "Bed Low Achieved" message through the Instrument Panel Cluster (IPC), when requesting lowering, even though the truck didn't physically lower. Ride height changes/valve actuations without operator request on rough roads.