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
| FL974 | 2024-03-06. 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. |
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| FL974 | 2024-02-06. Service bulletin. ENGINE AND ENGINE COOLING. Emissions Recall: Cummins DEF Sensor Shortage |
| SBW83-030 | 2022-07-02. Service bulletin. VISIBILITY. Updated Western Star Service Bulletin for HVAC Actuator Replacement |
| SBW83-030 | 2022-06-04. Service bulletin. VISIBILITY. Western Star Service Bulletin for HVAC Actuator Replacement. The wiring harness of the actuator of the fresh air recirculation door on Western Star vehicles equipped with Red Dot HVAC systems should be inspected for signs of water intrusion and corrosion. |
| ICI22-017 | 2022-05-03. Service bulletin. POWER TRAIN. Important Campaign Information Letter for DDC D21M1 Termination Date Extended. This letter is to inform you that a revised bulletin for Detroit Diesel Field Service Campaign D21M1, DT12 Transmission Drive Shaft Cover Plug Reseal has been EXTENDED for an additional three months. Please use the extended termination date for all work under D21M1 from this point forward. REVISION: D21M1 termination date extended to July 1, 2022. |
| SBW49-020 | 2022-03-03. Service bulletin. ENGINE AND ENGINE COOLING. Western Star Service Bulletin for DEF Connector Reinforcement Caps |
| CALWS83-001REV | 2022-01-04. Service bulletin. VISIBILITY. HVAC Actuator Wiring Harness. Revision History: Service kit part number changed from RDH RD5 17147 0 to WWS RD-3-9069-0 on 12/9/21. The wiring harness of the actuator of the fresh air recirculation door, shown in Fig. 1, on Western Star vehicles equipped with Red Dot HVAC systems should be inspected for signs of water intrusion and corrosion. |
| SF613 | 2021-11-03. Service bulletin. SERVICE BRAKES, HYDRAULIC. ConMet Front Hub to Rotor Fasteners. On certain vehicles, the front rotor nuts may not be torqued to manufacturer specification. Loose components could cause damage to the ABS tone rings, the ABS sensors, and the anchor plate mounting fasteners. |
| ICI21-030 | 2021-11-03. Service bulletin. VISIBILITY. SF626 Western Star Window Replacement Inspection Notification. This letter is to inform you that Field Service Campaign SF626 Western Star Window Replacement Inspection Notification campaign was released. |
| CALWS83-001 | 2021-09-29. Service bulletin. ELECTRICAL SYSTEM; VISIBILITY. Customer Advisory Letter for HVAC Actuator Wiring Harness. The wiring harness of the actuator of the fresh air recirculation door, shown in Fig. 1, on Western Star vehicles equipped with Red Dot HVAC systems should be inspected for signs of water intrusion and corrosion. |
| SBW54-080 | 2021-06-29. Service bulletin. ELECTRICAL SYSTEM. Western Star Service Bulletin for Key Fob ID Retention. Key fobs for remote keyless entry on Western Star vehicles are delivered in packages that include a unique ID for the fob. The ID is required when pairing the key fob with a vehicle. |
| SS708-WST2021 | 2021-06-26. Service bulletin. ELECTRICAL SYSTEM. Western Star Service Solution for Low Voltage Disconnect (LVD) Troubleshooting: Western Star 5700 and New 4700. |
| SS1033094 | 2021-06-09. Service bulletin. FUEL SYSTEM, GASOLINE; FUEL SYSTEM, GASOLINE:FUEL INJECTION SYSTEM:MANIFOLD PRESSURE (MAP) SENSOR. Service Solution SS 1033094 KUS Float Tube Fuel Level Sensor Inform... |
| WSTCAE180-2020 | 2021-05-18. Service bulletin. EQUIPMENT; EQUIPMENT ADAPTIVE/MOBILITY. Portland Truck Plant Paint Changes |
| D21M1 | 2021-05-01. Service bulletin. POWER TRAIN. Detroit Field Service Campaign for DT12 Transmission Drive Shaft Cover Plug Reseal. Daimler Trucks North America LLC, on behalf of its DETROIT Powertrain Division, is initiating Field Service Campaign D21M1 on certain DT12 transmissions in order to reseal the bypass plugs of the drive shaft cover located in front housing. |
| WI21-009 | 2021-04-24. 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. |
| WI21-008 | 2021-04-23. Service bulletin. EQUIPMENT. Warranty Information Letter announcing DTNA is adjusting the Standard Repair Times (SRTs) shown. The updated times will be applied to repair orders opened on or after April 5, 2021. |
| DT12 Trans Chafe | 2021-04-08. Service bulletin. EQUIPMENT; EQUIPMENT ADAPTIVE/MOBILITY; POWER TRAIN. DTNA received a field notification on multiple units regarding diagnostic fault codes that were found to be causing issues to the After Treatment Control Module (ACM). These fault codes indicated that the ACM communication message was not received by the Motor Control Module (MCM) which in certain cases, led to a 25% engine de-rate situation. Further diagnosis revealed that the DT12 wiring harness was chafing and contacting the transmission TCU case. To reduce potential chafing areas, the proposed short-term containment was to route the wiring harness using additional tie straps. This communication applies to Freightliner and Western Star vehicles built with DT12 transmissions. |
| TechTalk12312K | 2021-04-05. Service bulletin. VEHICLE SPEED CONTROL. Tech Talk discussion on suspended accelerator pedal being uncomfortable for ice road operation. |
| WP60-100 | 2021-03-25. Service bulletin. EQUIPMENT. Updated Western Star Parts Technical Bulletin for Universal Design Floor Mats. This bulletin replaces the version dated February 12, 2021. Information about parts notes in the Paragon system have been added and the trimming instructions are revised. Universal floor mat designs fit multiple cab configurations and may require trimming. Trim lines displaying size options are scored into the pad side of the mat; use an existing floor mat as a guide for optimal results. The new mat should not interfere with safety-critical equipment, such as foot pedals. |
| SBW54-057 | 2021-03-25. Service bulletin. EQUIPMENT; ELECTRICAL SYSTEM. Western Star Service Bulletin for Powernet Troubleshooting Guide - Batteries, Path, Alternator, and Starter. When troubleshooting powernet issues, use the BCT-460DTNA PowerNet Assessment Tool. As of May 29, 2018, the AutoMeter is the only Daimler-approved tool for troubleshooting vehicle Powernet issues. |
| WP21-007 | 2021-03-24. Service bulletin. EQUIPMENT; ELECTRICAL SYSTEM. Warranty Policy Letter for battery tags. DTNA determined that since adopting the AutoMeter BCT-460DTNA Powernet Assessment Tool (AutoMeter) as the required powernet system tester, not all battery tags have to be retained support Warranty-related claims. |
| WI21-004 | 2021-03-02. Service bulletin. POWER TRAIN; ENGINE AND ENGINE COOLING. Warranty Information Letter for Detroit Resources: Exploded View DD Platform and DT12 Posters. Detroit's TechComm team created visual aids for the network and released exploded view posters for DD platform engines. In early 2021, Detroit added multiple DT12 posters. |
| 21TS-04 | 2021-03-02. Service bulletin. ENGINE AND ENGINE COOLING. Technical Service Letter for Gen 5 DD15 Instrument Panel Oil Pressure Gauge Operation. Gen 5 DD15 equipped units have been brought in for service with a complaint of the instrument panel oil pressure gauge not moving during unit operation and/or stuck at 50PSI. The instrument panel oil pressure gauge does not operate the same as with previous engine models. Please be advised, this is normal operation and no further diagnostics are required. Do not down a unit for this complaint. |
| 21OEM-06 | 2021-03-01. Service bulletin. ENGINE AND ENGINE COOLING. Starting on November 23, 2020, DiagnosticLink 8.13 (Build 4527) was made available. Current subscribers of DiagnosticLink 8.11 or 8.12 may upgrade to DiagnosticLink 8.13 at no cost. All DTNA Service shops & OEM locations are required to maintain the latest version of software on each of their stations. |
The summaries are NHTSA's. Each bulletin's page links NHTSA's copy of the manufacturer's document.