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Service bulletins for the 2021 Mack MD

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.

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

By type

By component

By trouble code

Bulletins, newest first
CBR-2112 2023072023-08-02. Service bulletin. ELECTRICAL SYSTEM; POWER TRAIN; ENGINE AND ENGINE COOLING. CBR: Programming Failure - Chassis With Cummins Engine And An Allison Transmission
KC-474-Ver52023-06-05. Service bulletin. POWER TRAIN. CBR: Diagnostic Trouble Code (DTC) P215A-64, Fault Code SPN 84 FMI 19
M-773-005a2023-05-03. Service bulletin. WHEELS. TSB: Hub Cap, Leaking
M-773-0052023-04-04. Service bulletin. WHEELS. New TSB- Hub cap leaking
KC-21402022-12-05. Service bulletin. ELECTRICAL SYSTEM; PARKING BRAKE. Mack Chassis - P05E662 Park brake Sensor/Switch Circuit Range/Performance, Signal Compare failure - Diagnostic Instructions - US21+OBD21 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-21432022-07-05. Service bulletin. VEHICLE SPEED CONTROL. (Back Office) - Cruise Control Inoperative After Updating Software VECU5 Without ESP Package (UESP).
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-3992022-07-05. Service bulletin. ELECTRICAL SYSTEM. Vehicle Overspeed Warning Comes Active At A Lower Speed Than Expected; Vehicle Overspeed Warning In Driver Information Display (DID) - Model Year 2018 And Newer With New Style Instrument Cluster.
KC-4052022-07-05. Service bulletin. POWER TRAIN. Warranty Automated Manual Transmission ( AMT, I-Shift, mDrive ) Control Housing Assembly; Guidelines For Filing A Claim For Chassis Return Visit With Transmission Issues After A Repair Requiring Control Housing Removal And Reinstallation - US07 And N.
KC-5612022-07-05. Service bulletin. ENGINE AND ENGINE COOLING. 11L, 13L, And 16L Engine Oil Analysis Specifications - US10 And Newer Emissions
KC-7352022-07-05. Service bulletin. EQUIPMENT. Premium Tech Tool (PTT) - Message For Data Mismatch, Product Configuration Mismatch; Instruction To Run An Accessory Kit Displayed When Attempting To Run Diagnostics For Diagnostic Trouble Codes (DTC) Or Programming - US10+OBD13 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-7452022-07-05. Service bulletin. POWER TRAIN. Automated Manual Transmission ( AMT ) I-Shift / mDRIVE - Ribbon Harness Replacement - Speed Sensor Bolts, Possible Fault Codes P1058 - 21 Or MID 130 PID 161 FMI 1
KC-7502022-07-05. Service bulletin. ENGINE AND ENGINE COOLING. US10 Emission Engines - Diagnostic Trouble Code ( DTC ) SPN 1231 FMI 9 Troubleshooting.
KC-7512022-07-05. Service bulletin. POWER TRAIN. Vehicles Equipped With An Automated Manual Transmission Model D or F ( AMT-D, AMT-F ) - Transmission Oil Leakage From Transmission Input Shaft Seal Or Output Shaft Seal - US10 And Newer Emissions, Common Model Years 2010 And Newer.
KC-6632022-06-07. Service bulletin. ENGINE AND ENGINE COOLING. Emcon (Spark Assist) Engine Aftertreatment System Troubleshooting Check Sheet - US07 Emissions

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