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Service bulletins for the 2021 Kenworth T680

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.

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

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Only bulletins with component: Engine are shown. Show all

Bulletins, newest first
E3002023-04-04. Service bulletin. ENGINE AND ENGINE COOLING. PACCAR will reimburse customers for the local purchase of in-tank fuel additive for EPA2021 compliant MX engines. This is a one-time reimbursement. Only customers who have received E290 injector cleaning qualify for this reimbursement. See bulletin for limits and purchase tracking requirements.
03-087 (E295)2023-03-06. Service bulletin. FUEL SYSTEM, OTHER:FUEL FILTER; ENGINE AND ENGINE COOLING. Certain Model Year 2021-2024 chassis with PACCAR MX engines and optional fuel filter restriction virtual gauge may display incorrect restriction levels. The virtual gauge will be temporarily disabled until a revised sensor strategy is developed.
E3032023-02-06. Service bulletin. ENGINE AND ENGINE COOLING. This campaign is the final opportunity to replace the oil filter screw cap to reduce occurrences of broken bypass valve tabs. Broken oil valve tabs can cause oil flow obstruction to critical engine parts, resulting in serious engine damage. Customers that do not receive this repair may be responsible for progressive engine damage caused by broken oil bypass valve tabs.
41-0232022-11-02. Service bulletin. ENGINE AND ENGINE COOLING. Certain T680 NextGen air filter elements that may have been damaged due to excessive vibration were replaced without inspecting the air intake system for dust intrusion. Those vehicles must be inspected to assess possible progressive damage."
45-0642022-11-02. Service bulletin. ENGINE AND ENGINE COOLING. Info Only - PACCAR is introducing Over-the-Air (OTA) software updates for engine MY17 and newer chassis equipped with Cummins X15, X12, ISX12, ISX12N, L9N, PX-7, and PX-9 engines The technology will leverage the existing Remote Diagnostic cs hardware to deliver secure software updates remotely. This will reduce downtime and save on maintenance costs for eligible vehicles.
E2962022-08-30. Service bulletin. ENGINE AND ENGINE COOLING. Kenworth is providing guidance for PACCAR MX Engine Composite Oil Pan leak troubleshooting to avoid over-repairs and to provide warrantable repair guidance. Oil leaks, if not repaired, can lead to severe engine damage.
42-0602022-06-02. Service bulletin. ENGINE AND ENGINE COOLING. Fix As Fail - Certain chassis, equipped with an RCX230 Horton fan clutch and a Cummins X15 or ISX12N engine, are experiencing an adapter harness failure. This failure causes the fan to remain activated while the truck is in operation and may result in a check engine light and diagnostic trouble codes.
E2862022-04-05. Service bulletin. ENGINE AND ENGINE COOLING; EQUIPMENT. Engine Model Year 2021B and later PACCAR MX-11 and MX-13 Fuel Injector Adjustment During First C Service
E2802022-01-06. Service bulletin. ENGINE AND ENGINE COOLING. Non-Safety Campaign: Certain DC tools were incorrectly calibrated. The resulting torque issue could affect the EPA21 MX-11 and MX-13 Oil Pan and/or the Exhaust Manifold.
E2822022-01-06. Service bulletin. ENGINE AND ENGINE COOLING. Information Only: Due to differences between the PACCAR MX-11 or MX-13 2021A and 2021B engines, technicians must be able to identify which of these engines are in a chassis.
21KWD2021-07-06. Service bulletin. ENGINE AND ENGINE COOLING. Information Only – C hassis equipped with MY2021 B EPA emission s standards will be shipped through atleast the end of the 2021 calendar year without particulate matter (PM) sensors installed .
32-0182021-03-10. Service bulletin. ENGINE AND ENGINE COOLING. Non-Safety Campaign – Chassis with the City Horn option may generate unexpected alerts. A VECU software update is available to resolve the issue.
E2752021-01-06. Service bulletin. ENGINE; EQUIPMENT:OTHER:LABELS; ENGINE AND ENGINE COOLING:EXHAUST SYSTEM:EMISSION CONTROL. Non-Safety Campaign - Vehicles included in Model Year 2021 Pre-Production Engine program have an Emissions Exemption label that must be replaced. The current Emissions Exemption label will expire on 12/31/2020 and requires a new label to extend the exempt

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