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Service bulletin 25-008-24

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 id11010636
Published by NHTSA2024-11-18
Manufacturer's number25-008-24
Manufacturer's date2024-11-14
NHTSA componentUNKNOWN OR OTHER
Manufacturer's systemDiesel Exhaust Fluid

NHTSA's summary

"Flash: Diesel Exhaust Fluid (DEF) Dosing Control Unit (DCU) Update Customers must experience a Malfunction Indicator Lamp (MIL) illumination and the vehicle must exhibit/set the following Diagnostic Trouble Code (DTC): ● P21C4-00 - Reductant Line Heater Relay Control Circuit High. ● U11C1-00 - Reductant Control Module Received Implausible Data From ECM/PCM. These DTCs will occur after installation of service DCU 68458603AB. This bulletin involves reprogramming the DCU with the latest available software."

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.

Trouble codes named

P21C4, U11C1

Vehicles listed
RAM 25002019, 2020, 2021, 2022, 2023, 2024
RAM 35002019, 2020, 2021, 2022, 2023, 2024
RAM 45002019, 2020, 2021, 2022, 2023, 2024
RAM 55002019, 2020, 2021, 2022, 2023, 2024

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