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Service bulletins for the 2020 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.

177 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
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
K595542552020-05-05. Service bulletin. ENGINE AND ENGINE COOLING. EXPIRED - Refer To K47547856 - Debranded Solutions - Mack Chassis - Particulate Matter (PM) Sensor Diagnostic Trouble Codes (DTC) Illuminating The Malfunction Indicator Lamp (MIL); Tech Tip TT-014-2016 - US14+OBD16, US17+OBD16 And Newer Emissions, Common Model Year 2017 And Newer - To Be Used For EVERY Visit
K011572832020-04-06. Service bulletin. 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
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
K535805142020-01-13. Service bulletin. EQUIPMENT ADAPTIVE/MOBILITY; EQUIPMENT; ENGINE. Brake Drum Inspection - Checking Runout, Wear, And Other Characteristics
K250360452020-01-13. Service bulletin. EQUIPMENT; ENGINE. Mack Chassis - Diagnostic Trouble Code ( DTC ) SPN4094, Check List - US10 Emissions
K292957442020-01-13. Service bulletin. EQUIPMENT ADAPTIVE/MOBILITY; ENGINE AND ENGINE COOLING:ENGINE:DIESEL; EQUIPMENT. Updated PM Sensor Removal Procedure - US17+OBD16 and Newer Emissions
K889928922020-01-13. Service bulletin. FUEL SYSTEM, GASOLINE; ENGINE; EQUIPMENT; EQUIPMENT ADAPTIVE/MOBILITY. Assembled Camshaft - Injector Lobe Rotation Inspection For Possible Spun Camshaft Lobe; Diagnostic Trouble Codes (DTC) P0257-00, P2A17-00, Or P2A1F-00, Possible Lack Of Power - US17+OBD16 and Newer Emissions
K300241432019-10-28. Service bulletin. ENGINE AND ENGINE COOLING. Mack Chassis - Oil Diluted With Fuel; Fuel In Oil, Diagnostic Information - All Emissions Prior To US17+OBD16 (Common Rail Fuel System), Model Year 2017 And Older
K869000432019-07-15. Service bulletin. ENGINE AND ENGINE COOLING. Exhaust Gas Recirculation (EGR) System - Fault Codes SPN 412 FMI 0,2,5; Diagnostic Trouble Codes (DTC) P040A, P040B, P1121 - Temperature Sensor Inspection

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