# 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 bulletins from NHTSA, as of 2026-10-19.

- [CBR 2573\-1 202604](/bulletins/11032092.md), 2026-05-05, Service bulletin: POWER TRAIN. CBR \- Mack Chassis \- Through Shaft Bearing Retainer Breakage On Mack Carriers.
- [CBR 2362\-3 202604](/bulletins/11032086.md), 2026-05-04, Service bulletin: POWER TRAIN. CBR \- Mack Carrier Nut Adhesive Change.
- [CBR 2712\-7 032026](/bulletins/11030579.md), 2026-04-02, Service bulletin: ELECTRICAL SYSTEM; UNKNOWN OR OTHER. CBR \- No Start Condition After Over the Air Programing.
- [CBR 2107\-22 202601](/bulletins/11028032.md), 2026-02-02, Service bulletin: ENGINE. CBR \- Mack DEF Level \(UQLS\) Sensor Troubleshooting Guide \- US17\+OBD16 Emissions to US22\+OBD2023 \(DOES NOT APPLY TO AN\(4\) and PR\(4\)\).
- [CBR 2171\-11 202511](/bulletins/11026025.md), 2025-12-03, Service bulletin: ENGINE; ELECTRICAL SYSTEM. CBR \- Mack Temperature Sensor Troubleshooting Guide
- [CBR 2515\-1 102025](/bulletins/11024783.md), 2025-11-03, Service bulletin: STEERING. CBR \- Hard Steering Due to Steering Column Miter Box Corrosion – Inspection and Replacement Procedure
- [CBR 2172\-5 082025](/bulletins/11022289.md), 2025-09-02, Service bulletin: ELECTRICAL SYSTEM. CBR \- When an OTA \(Over\-The\-Air\) job starts to program the VECU blocks the starter relay out, if the job ends in a Critical failure, the vehicle will remain in Safe State.
- [CBR 407 072025](/bulletins/11021333.md), 2025-08-04, Service bulletin: SERVICE BRAKES; ELECTRICAL SYSTEM. CBR \- To correct the MID136 SID 66 FMI 7 fault code the latest Bendix VCP file will need to downloaded.
- [CBR 2488 072025](/bulletins/11021332.md), 2025-08-04, Service bulletin: ELECTRICAL SYSTEM. CBR \- A significant GPS reporting issue is affecting fleet operations, with trucks maintaining back\-office communication but failing to transmit GPS location data.
- [CBR 2107\-21 202505](/bulletins/11018813.md), 2025-06-02, Service bulletin: FUEL/PROPULSION SYSTEM; ENGINE. Mack DEF Level \(UQLS\) Sensor Troubleshooting Guide \- US17\+OBD16 Emissions and Newer
- [CBR 901\-5 202505](/bulletins/11018811.md), 2025-06-02, Service bulletin: ELECTRICAL SYSTEM. Remote Control Central Door Lock, Programming; Key Fob Cannot Be Programmed Or Does Not Work After Programming \- Model Year 2018 And Newer
- [CBR 445\- 11 202505](/bulletins/11018806.md), 2025-06-02, Service bulletin: FUEL/PROPULSION SYSTEM. Vehicles Equipped With a Common Rail Fuel System \- Aftermarket Secondary Fuel Filters, Important Information On Approved Filters \- US17\+OBD16 toUS21\+OBD23
- [CBR 170\-8 202505](/bulletins/11018804.md), 2025-06-02, Service bulletin: ENGINE. Inactive Code P25AE00 Being Generated After A Hard Pull And A Momentary Drop In Engine Oil Pressure \(Low Oil Pressure\) \(Possible Related Codes \- SPN4811 , SPN 100 , PID 100\)
- [CBR\-561 202503](/bulletins/11016342.md), 2025-04-02, Service bulletin: ENGINE. If oil dilution is suspected refer to the applicable CBR solution below: ∙ CBR\-659􀁡Mack Chassis \- Oil Diluted With Fuel; Fuel In Oil, Diagnostic Information \- All Emissions, All Model Years
- [CBR\-2016 202412](/bulletins/11012156.md), 2025-01-02, Service bulletin: SUSPENSION. Frame lean can be caused by several seemingly isolated possibilities. The two most common are suspension and frame assembly issues.
- [CBR\-997 202411](/bulletins/11010857.md), 2024-12-02, Service bulletin: ENGINE. Vehicles may present with oil leak coming from the clutch/flywheel housing and observation of burned clutch smell or clutch slipping. These symptoms can be mistaken as a crankshaft rear main seal leak, when the actual cause is the crankshaft adaptor O\-ring.
- [CBR\-2263 202410](/bulletins/11009705.md), 2024-11-04, Service bulletin: ENGINE. CBR \- Mack Chassis \- Timing Gear Plate Repair
- [CBR\-731 202409](/bulletins/11008377.md), 2024-10-03, Service bulletin: POWER TRAIN. CBR: Automated Manual Transmission \(AMT\) Model D or F \(mDrive and I\-Shift, AMT\-D, AMT\-F\) \- Transmission Oil Leakage From Transmission Input Shaft Seal Or Output Shaft Seal \- US10 And Newer Emissions, Common Model Years 2010 And Newer
- [CBR\-570 202409](/bulletins/11008374.md), 2024-10-03, Service bulletin: ELECTRICAL SYSTEM; FUEL/PROPULSION SYSTEM. CBR: US17 GHG Common Rail Fuel System Component Electrical Faults \- Model Year 2017 To 2024
- [CBR\-471 202409](/bulletins/11008368.md), 2024-10-03, Service bulletin: ELECTRICAL SYSTEM. CBR: The procedure to eliminate the Mack Chassis "Air Restriction Light On" seen in the cluster is to confirm that the parameter YYT is set to "Enable" with Premium Tech Tool.
- [CBR\-407 202409](/bulletins/11008366.md), 2024-10-03, Service bulletin: SERVICE BRAKES. CBR: To correct the MID136 SID 66 FMI 7 fault code the latest Bendix VCP fi le will need to be downloaded.
- [CBR\-2391 202408](/bulletins/11006927.md), 2024-09-04, Service bulletin: ELECTRICAL SYSTEM; POWER TRAIN. CBR: Diagnostic Trouble Code \(DTC\) U010187\- Lost Communication With TECU
- [CBR\-561 202408](/bulletins/11006925.md), 2024-09-04, Service bulletin: ENGINE. CBR: 11L, 13L, And 16L Engine Oil Analysis Specifications \- US10 And Newer Emissions
- [CBR\-523 202408](/bulletins/11006924.md), 2024-09-04, Service bulletin: ENGINE. CBR: Overhead Wear Overview \- Model Year2018 To Current \(Common Rail Fuel System ONLY\)
- [CBR\-2350 202407](/bulletins/11005410.md), 2024-08-01, Service bulletin: ELECTRICAL SYSTEM. CBR: Telematics Gateway \(TGW\) Connect Ability Issues

More: [the next page](/v1/vehicles/2021_mack_lr/bulletins?cursor=2024-08-01_11005410) (JSON)

JSON: [/v1/vehicles/2021_mack_lr/bulletins](/v1/vehicles/2021_mack_lr/bulletins)

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