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Service bulletin CBR-2591-1 202606

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.

The communication, as NHTSA indexes it (as of 2026-10-19)
TypeService bulletin
NHTSA id11034133
Published by NHTSA2026-06-29
Manufacturer's numberCBR-2591-1 202606
Manufacturer's date2026-06-16
NHTSA componentENGINE

NHTSA's summary

The purpose of this CBR it to provide release notes for the recent Engine ECU software.

The document

The document is the manufacturer's. This site does not hold it. NHTSA files a document at one of these two addresses; we have not asked NHTSA which.

Components

Engine

Vehicles listed
MACK ANTHEM AN (4)2026, 2027 (the catalog's model; the bulletin names a series or trim of it)
MACK PIONEER PR (4)2025, 2026, 2027 (the catalog's model; the bulletin names a series or trim of it)

Listing a model year does not mean every vehicle of it is concerned: the document says which.

Other bulletins for the same vehicles and component
TSB M-913-001 2026092026-10-02. Service bulletin. Parker engine-mounted hydraulic pump service bulletin.
TSB M257005 2026082026-09-01. Service bulletin. Loose CCV mounting bolts and oil leak at CCV due to cracking of the housing. Mounting hardware found to be under-torqued after the vehicle was delivered.
CBR 2596 2026082026-09-01. Service bulletin. The purpose of this CBR is to provide steps on how to correct a customer complaint of a no crank/engine start condition.
CBR-2592-1 2026062026-06-29. Service bulletin. The purpose of this CBR is to provide steps on how to correct a customer complaint of DTC P107B86 accompanied With intermittent loss of throttle.
CBR-2586-1 2026062026-06-29. Service bulletin. The purpose of this CBR is to address issues of exhaust stack rotation on version 4 products.
CBR 2465-6 2026052026-06-02. Service bulletin. CBR to diagnosis issues with the Proactive Engine Restart system and Hood Open message.
S4757 0220262026-03-03. Service campaign. SC - Certain model AN(4)’s and PR’s could experience DEF leaks or crystallization due to the installation of incorrect fasteners for the Urea Dosage Valve.
SC S4742 2026012026-02-03. Service campaign. CBR MCO/VECI Label Reprint.
CBR 2522-5 2026012026-02-03. Service bulletin. CBR - Frequent Parked Regeneration Requests - Models PR (4), AN (4).
CBR 2535 2025122026-01-05. Service bulletin. The purpose of this CBR is to address reports of regeneration failure when ambient temperature is below 30F.