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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-21282023-04-04. Service bulletin. ENGINE AND ENGINE COOLING:EXHAUST SYSTEM:EMISSION CONTROL; ELECTRICAL SYSTEM. Engine Control Module (EMS) Software Information - Improvement List (Change Log), March 2023 – US21+OBD2021 Emissions ONLY
S76272023-03-07. Service bulletin. ENGINE AND ENGINE COOLING. Mack MMD Alternator Pulley
KC-21652023-03-07. Service bulletin. ENGINE AND ENGINE COOLING. Mack DEF Pump Troubleshooting Guide - US10+OBD13 And Newer Emissions
M-212-0012023-01-04. Service bulletin. ENGINE AND ENGINE COOLING. Timing Gear Plate Inspection
KC-21652022-11-03. Service bulletin. ENGINE AND ENGINE COOLING; ENGINE AND ENGINE COOLING:EXHAUST SYSTEM. Mack DEF Pump Troubleshooting Guide - US10+OBD13 And Newer Emissions
M-265-0022022-10-06. Service bulletin. ENGINE AND ENGINE COOLING. TSB-Charge Air Cooler t-clamp install.
CBR-21312022-09-08. Service bulletin. ENGINE AND ENGINE COOLING. USE FOR NEW VEHICLES (US21+OBD22 Emissions) - Intermittent Diagnostic Trouble Codes U02A3, U029D, U029E
KC-21392022-09-07. Service bulletin. ENGINE AND ENGINE COOLING; FUEL SYSTEM, DIESEL. fuel in the oil inspection
KC-7332022-07-05. Service bulletin. ENGINE AND ENGINE COOLING. Back Office Mack Chassis - Secondary Gauge Set Up - Model Year 2018 and Newer.
KC-21072022-07-05. Service bulletin. ENGINE AND ENGINE COOLING. DEF Level (UQLS) Sensor Troubleshooting Guide - US17+OBD16 Emissions and Newer.
KC-21122022-07-05. Service bulletin. ELECTRICAL SYSTEM; POWER TRAIN; ENGINE AND ENGINE COOLING. Programming Failure - Chassis With Cummins Engine And An Allison Transmission
KC-21162022-07-05. Service bulletin. ENGINE AND ENGINE COOLING. NOx Sensor Troubleshooting Guide - US10+OBD13 And Newer Emissions.
KC-21572022-07-05. Service bulletin. ENGINE AND ENGINE COOLING; FUEL SYSTEM, GASOLINE. Aftertreatment Hydrocarbon Injector (AHI) Troubleshooting Guide - US10+OBD13 And Newer Emissions.
KC-21582022-07-05. Service bulletin. ENGINE AND ENGINE COOLING. Selective Catalytic Reduction (SCR) Muffler Troubleshooting Guide - US10+OBD13 And Newer Emissions.
KC-21652022-07-05. Service bulletin. ENGINE AND ENGINE COOLING. DEF Pump Troubleshooting Guide - US10+OBD13 And Newer Emissions.
KC-5612022-07-05. Service bulletin. ENGINE AND ENGINE COOLING. 11L, 13L, And 16L Engine Oil Analysis Specifications - US10 And Newer Emissions
KC-7362022-07-05. Service bulletin. ENGINE AND ENGINE COOLING. (Back Office Only) - Engine Brake Vibration When In High Setting - 13L Engine With Variable Geometry Turbo ( VGT ) - US17 And Newer Emissions (Common Rail Fuel System).
KC-7502022-07-05. Service bulletin. ENGINE AND ENGINE COOLING. US10 Emission Engines - Diagnostic Trouble Code ( DTC ) SPN 1231 FMI 9 Troubleshooting.
KC-6632022-06-07. Service bulletin. ENGINE AND ENGINE COOLING. Emcon (Spark Assist) Engine Aftertreatment System Troubleshooting Check Sheet - US07 Emissions
KC-6442022-06-07. Service bulletin. ENGINE AND ENGINE COOLING. Manual Compression Test Adapter For Engines With Stainless Steel Injector Sleeves (Conical Tip Injectors) - US07 And Newer Emissions, Model Year 2008 And Newer
KC-21712022-06-07. Service bulletin. ENGINE AND ENGINE COOLING. Temperature Sensor Troubleshooting Guide - US10+OBD13 And Newer
KC-21652022-06-07. Service bulletin. ENGINE AND ENGINE COOLING. DEF Pump Troubleshooting Guide - US10+OBD13 And Newer Emissions
KC-21612022-06-07. Service bulletin. ENGINE AND ENGINE COOLING. DEF Pump Cycling periodically Hours After Key Off
KC-21582022-06-07. Service bulletin. ENGINE AND ENGINE COOLING. Selective Catalytic Reduction (SCR) Muffler Troubleshooting Guide - US10+OBD13 And Newer Emissions
KC-21572022-06-07. Service bulletin. ENGINE AND ENGINE COOLING. Aftertreatment Hydrocarbon Injector (AHI) Troubleshooting Guide - US10+OBD13 And Newer Emissions

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