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Service bulletins for the 2021 Western Star 4900

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.

117 on file from NHTSA, as of 2026-10-19.

By type

By component

Only bulletins with component: Engine are shown. Show all

Bulletins, newest first
CXA 03_26_Surge Tank2026-04-02. Other. ENGINE. CX Advocate for discolored coolant surge tanks (24CSA-20)
CXA_10_25_Conmet Oil Pan2025-11-05. Other. ENGINE. CX Advocate for ConMet Oil Pan Insert Additional Issues
24CSA-19Rev2025-09-02. Other. ENGINE. Revised Customer Service Annoucement for No Trouble Found Heavy Duty Engine Product (HDEP) Oil Separator Leaks
CXA 3_25_NOx2025-04-02. Other. ENGINE. CX Advocate for NOx conversion low faults
CXA 2_25_NOx2025-03-04. Other. ENGINE. CX Advocate for NOx conversion low faults
CXA 1_16_NOx2025-01-29. Other. ENGINE. CX Advocate for NOx conversion low faults
SS1023366-Detroit2024-11-06. Other. ENGINE. Service Solution for Detroit Successful Regen Reference for GHG17 DD Engines
24CSA-202024-11-06. Service bulletin. ENGINE. Customer Service Annoucement for Discolored Coolant Surge Tank on Heavy Duty Engine Product (HDEP)
24CSA-192024-11-06. Other. ENGINE. Customer Service Annoucement for Heavy-Duty Engine Product (HDEP) Oil Separator Leaks
SS1023366-Detroit2024-10-04. Other. ENGINE. Service Solution for Detroit Successful Regen Reference for GHG17 DD Engines
CXA 8_24_Conmet Oil Pan2024-09-07. Other. ENGINE. CX Advocate for ConMet Oil Pan Insert Additional Failures
CXA 8_24_AutoElevate Disa2024-09-07. Other. ENGINE. CX Advocate for AutoElevate Disablement Gen5 Engines
CXA 8_24_AutoElevate and2024-09-07. Other. ENGINE. CX Advocate for benefits of Autoelevate and hydrocarbon faults
CXA 7_24_NOx2024-08-02. Other. ENGINE. CX Advocate for NOx conversion low faults. Update to CXA 6_24_NOx submission.
CXA 7_24_Conmet Oil Pan2024-08-02. Other. ENGINE. CX Advocate for ConMet Oil Pan Insert Additional Failures
CXA 7_24_AutoElevate Disa2024-08-02. Other. ENGINE. CX Advocate for AutoElevate Disablement Gen5 Engines
CXA 06_24_NOx2024-07-09. Other. ENGINE. CX Advocate communication for NOx conversion low faults
VSWP Customer Letter2024-06-22. Other. ENGINE. Customer letter regarding variable speed water pump.
SS763-WST2024-06-05. Other. ENGINE. Service Solution for DEF Pump Wiring for Cummins CM2450 Engine Controller
SS3144-FTL2024-05-07. Service bulletin. ENGINE AND ENGINE COOLING. Service Solution for DEF Pump Wiring for Cummins CM2450 Engine Controller
ICI24-0062024-03-06. Service bulletin. ENGINE AND ENGINE COOLING. Important Campaign Information letter for FL974 - Revised Bulletin & Population
FL9742024-03-06. Service bulletin. ENGINE AND ENGINE COOLING. Revised Emissions Recall: Cummins DEF Sensor Shortage. REVISION: Some vehicles formerly in Group F have been moved to Group G and have been assigned a new part number as specified in Table 1. An SRT for 'Calibration Code Only: Update or Confirm' has been added, as shown in Table 2, to be used when a new DEF header is not required. There have been some other minor changes to the work instructions and SRT times.
FL9742024-02-06. Service bulletin. ENGINE AND ENGINE COOLING. Emissions Recall: Cummins DEF Sensor Shortage
SBW49-0202022-03-03. Service bulletin. ENGINE AND ENGINE COOLING. Western Star Service Bulletin for DEF Connector Reinforcement Caps
WI21-0092021-04-24. Service bulletin. ENGINE AND ENGINE COOLING. Warranty Information letter announcing that DTNA is increasing the Standard Diagnostic Times (SDTs) shown. The updated after treatment system (ATS) diesel exhaust fluid (DEF) pump times will be applied to repair orders opened on or after April 12, 2021.

The summaries are NHTSA's. Each bulletin's page links NHTSA's copy of the manufacturer's document.