2018 Kenworth T600

The Office of Defects Investigation (ODI) opened this Preliminary Evaluation (PE21-015) based on one Vehicle Owner Questionnaire (VOQ) and supporting fleet reports. The reports indicated that the subject quarter fenders were prone to cracking and/or separation.After a comprehensive review of the data related to the quarter fender failures on the subject vehicles, ODI did not identify the existence of a safety-related defect trend. Quarter fender failures resulted in a warranty claim rate less than one percent (<1%) of the total vehicle population. All separations, including those due to tread separations, road hazards, etc., accounted for less than point one percent (<0.1%) of the total vehicle population.ODI discovered that the minimum recommended gap between the top of the quarter fender and the bottom of the trailer was not known or being followed. The optional quarter fenders were supplied by Fontaine Spray Systems (FSS), who recommended a two inch (2) gap. ODI analyzed the claim data using a calculated gap. A calculated gap using the top of the quarter fender flap and assuming the trailer is level with the top of the fifth wheel hitch was necessary, as PACCAR doesn't know specifically what trailer a purchaser will couple to the tractor. It is safe to assume no trailers on the market extend below the upper fifth wheel plate, but many do provide additional clearance over the wheels where the quarter fenders are located. ODI determined that 94 percent of warranty claims and 84 percent of separations violated FSS' recommendation.ODI confirmed that the VOQ vehicle and the fleet report vehicles also violated FSS' recommended gap. In one fleet the gap was negative point three inches (-0.3).PACCAR has updated its vehicle specification process and issued a customer advisory notice to existing owners. In light of the low rate of reported failures and separations, further use of agency resources does not appear to be warranted. The closing of this investigation does not constitute a finding by NHTSA that no safety-related defect exists. The agency reserves the right to take further action if warranted by the circumstances.

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.

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.

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.

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.

Information Only – Windshield washer pumps have a high No Trouble Found rate. Washer pumps may fail to spray due to a clogged filter.

Fix-As-Fail - Prior versions of Eaton Endurant transmission software may be prone to setting Linear Clutch Actuator (LCA) fault codes leading to possible LCA hardware replacement.