WenmarOpen by Wenmar Pro

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.

By type

By component

By topic

Bulletins, newest first
43-0722023-07-05. Service bulletin. ENGINE AND ENGINE COOLING:EXHAUST SYSTEM; ENGINE AND ENGINE COOLING. Certain chassis with Engine Model Year 2016-2021 PACCAR MX-11/MX-13, or EPA13 and EPA21 Cummins ISX12/ISX15/X15 engines that had a previously failed DEF sensor and with DEF sensor software disabled due to industry DEF sensor shortages will now be able to receive a replacement DEF sensor, DEF tank heater coolant control valve, and re-enabled DEF diagnostic software. Please note that chassis equipped with PACCAR PX engines will be eligible for this repair at a future date when software is available.
02-1762023-05-05. Service bulletin. STRUCTURE. T680 NextGen A-pillar fairing adhesive is not properly securing the fairing to the A-pillar. Procedures are available to apply new adhesive to the A-Pillar fairing.
E2902023-04-04. Service bulletin. ENGINE AND ENGINE COOLING. FIX-AS-FAIL Updated procedures and claim filing information. EPA2021 injector cleaning is referenced in RMI for certain injector faults. Complete the procedures in E290. Refer to E300 for in-tank additive information
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.
22KWB2022-06-02. Service bulletin. STEERING. Safety Recall – Interim Notification - The Dana D-Series front axle steer arm fasteners that attach the steer arm to the steering knuckle may fail, increasing the risk of a crash or injury. Repair information will be added when a repair procedure and parts are available.
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
98-0202022-04-05. Service bulletin. EQUIPMENT. nformation Only – New Level 1 required tools are available to support MY21B MX engines.
51-0132022-03-04. Service bulletin. EQUIPMENT; ELECTRICAL SYSTEM. Due to major data carriers phasing out 3G networks, chassis currently utilizing first generation Peoplenet Mobile Gateway (PMG001) will experience severe 3G service degradation as early as January of 2022. Chassis currently utilizing 3G antennas as a primary antenna may experience this degradation
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.
43-0712021-10-05. Service bulletin. FUEL SYSTEM, DIESEL. Fix-As-Fail – Due to undersupply issues, only a limited supply of Diesel Exhaust Fluid (DEF) sensors are available. As a temporary solution, after PACCAR confirms a DEF sensor is not available, a temporary software update will allow a vehicle to continue operation with a failed DEF sensor by disabling the DEF sensor diagnostics.
02-1682021-10-05. Service bulletin. STRUCTURE. Information Only - Rear axle Quarter Fenders with less than two inches of clearance between the top of the quarter fender and the bottom of the trailer/equipment are susceptible to damage. The lack of clearance could result in cracked/broken quarter fenders or complete separation if undetected or un-remedied.
21-KWE2021-09-03. Service bulletin. ELECTRICAL SYSTEM; VISIBILITY:DEFROSTER/DEFOGGER/HVAC SYSTEM. Safety Recall – Interim Notification - Certain Mahle HVAC control heads may have a soldering defect which may result in inoperative HVAC controls. Inoperative HVAC defrost may reduce driver visibility, increasing the risk of an accident. This bulletin will be updated when parts become available.
43-0692021-09-03. Service bulletin. EQUIPMENT; ELECTRICAL SYSTEM. A DPF regeneration two-position switch parameter is causing inhibited DPF regeneration. A parameter update, via Cummins Insite, restores proper DPF regeneration function.
02-1632021-08-05. Service bulletin. STRUCTURE; EQUIPMENT. "Non-Safety Campaign - A vinyl camouflage wrap was applied to T680 NextGen built during the pre-production phase of the product launch. The wrap can now be removed."
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 .
02-1602021-03-10. Service bulletin. VISIBILITY; EQUIPMENT; EQUIPMENT ADAPTIVE/MOBILITY; VISIBILITY:WINDSHIELD WIPER/WASHER. Information Only – Windshield washer pumps have a high No Trouble Found rate. Washer pumps may fail to spray due to a clogged filter.
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.
32-0172021-03-10. Service bulletin. ELECTRICAL SYSTEM. Non-Safety Campaign – The batteries may drain quickly due to the VECU not going to sleep. Updated VECU software is available to resolve the issue.

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