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Service bulletins for the 2020 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.

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

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Bulletins, newest first
E3112025-09-03. Other. ENGINE; POWER TRAIN. Condition, Chassis Affected, and Warranty sections updated with the following verbiage “E311 must be flagged and open in Service Information Record (SIR) at the time of RO open date to qualify.” Also, “Through Standard Warranty or any applicable active Extended Warranty” verbiage was removed from Warranty section.
E3162024-06-04. Service campaign. ENGINE. Campaign Certain PACCAR MX-13 engines contain bolts for the main bearing caps which may fail under certain conditions.
24KWD2024-05-04. Service bulletin. SERVICE BRAKES, AIR. Certain C500/T440/T470/T660/T680/T800/T880/W900 chassis may have air tank reservoirs that do not meet air volume requirements per FMVSS/CMVSS 121 “Air Brake Systems”. This bulletin will be updated when repair parts and procedures are available.
04-0222023-10-03. Service bulletin. STRUCTURE. Replacement fuel bezels are available for T680 Next Gen fairings. New bezels have updated attachments to prevent the bezel from becoming loose.
45-0652023-10-03. Service bulletin. ENGINE AND ENGINE COOLING; POWER TRAIN. Certain T680 Next Gen Cummins X15 have fan hub bracket hardware that is under torqued and could become loose and/or fail. Procedures are available to replace and properly torque the hardware.
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.
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.
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.
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
R21032022-02-04. Service bulletin. ENGINE AND ENGINE COOLING. Retrofit - The emissions exemption will be expiring on 5/15/2022 for certain pre-production vehicles equipped with PACCAR MX-11 and MX-13 EPA 2021 Emissions engines. Production-level components are now available to make these vehicles compliant.
T0122022-01-06. Service bulletin. POWER TRAIN. Non-Safety Campaign: Drivers of vehicles equipped with PACCAR TX-12 transmissions may experience harsh shifts and gear grinding noise. Premature Main Drive Gear damage may occur due to clutch housing and main case countershaft bearing bore wear.
26-0382022-01-06. Service bulletin. POWER TRAIN. Non-Safety Campaign: Eaton Endurant transmissions may experience premature Main Drive Gear damage due to clutch housing and main case countershaft bearing bore wear. A Clutch Housing Front Cover Kit will be installed to address the issue.
42-0592021-12-02. Service bulletin. ENGINE AND ENGINE COOLING:COOLING SYSTEM:FAN; ENGINE AND ENGINE COOLING. Non-Safety Campaign â“ Vehicles with a Cummins X15 engine and Horton fan drive may set Diagnostic Trouble Code (DTC) 6637 and/or 3838 due to fan speed that results in the fan remaining activated until the power is cycled. A new controller will resolve the issue.
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.
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.
51-0082021-02-01. Service bulletin. EQUIPMENT. T680 predictive cruise control(PCC) incompatibility with cummins engine.
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.