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Service bulletins for the 2021 Mack LR

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.

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

By type

By component

By trouble code

Only bulletins with component: Engine are shown. Show all

Bulletins, newest first
KC-1302021-11-05. Service bulletin. ENGINE AND ENGINE COOLING:ENGINE:ENGINE CONTROL MODULE (ECU/ECM); FUEL SYSTEM, OTHER. Air In The Fuel System Tests, Common Rail Fuel System - US17+OBD16 and Newer Emissions
KC-21392021-09-02. Service bulletin. ENGINE AND ENGINE COOLING. 11 Liter Engines - Fuel In Oil - Vehicles Built Between October 2020 And June 2021
S75762021-08-02. Service bulletin. ENGINE AND ENGINE COOLING; EQUIPMENT. VECU Software Update
CBR-152021-07-06. Service bulletin. ENGINE AND ENGINE COOLING. Diagnostic Trouble Codes (DTC) For The Engine Pre-Heat Relay: Supplementary Instructions
S75572021-03-03. Service bulletin. ENGINE AND ENGINE COOLING; ELECTRICAL SYSTEM. VECU Active code and no MIL Lights
SNM21-0012021-02-01. Service bulletin. ENGINE AND ENGINE COOLING. Improved method for determining which DTC to troubleshoot in a MIL on situation
K533380752020-06-03. Service bulletin. ENGINE AND ENGINE COOLING. Diagnostic Trouble Codes (DTC) For The Engine Pre-Heat Relay: Supplementary Instructions - US10+OBD13 And Newer Emissions, Model Year 2014 And Newer
K475478562020-05-06. Service bulletin. ENGINE AND ENGINE COOLING; EQUIPMENT. Particulate Matter (PM) Sensor Diagnostic Trouble Codes (DTC) Illuminating The Malfunction Indicator Lamp (MIL) - US14+OBD16, US17+OBD16 And Newer Emissions, Model Year 2017 And Newer - To Be Used For EVERY Visit
K011572832020-04-03. Service bulletin. EQUIPMENT; ENGINE AND ENGINE COOLING:ENGINE:GASOLINE:BELTS AND ASSOCIATED PULLEYS; ELECTRICAL SYSTEM. Front Accessory Drive Noise, Alternator Belt Wear, Alternator Belt Tensioner Failure - Model Year 2017 And Newer
S74542020-03-09. Service bulletin. ENGINE. Modify Air Dryer TCOV

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