# Service bulletin TSB M257005 202608

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.

- Type: Service bulletin
- NHTSA id: 11036590
- Published by NHTSA: 2026\-09\-01
- Manufacturer's number: TSB M257005 202608
- Manufacturer's date: 2026\-08\-26
- NHTSA component: ENGINE

## NHTSA's summary

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.

## The document

- [NHTSA's copy of the document (PDF)](https://static.nhtsa.gov/odi/tsbs/2026/MC-11036590-0001.pdf)
- [If that address does not open, try this one](https://static.nhtsa.gov/odi/tsbs/2026/MC-11036590-9999.pdf)

The document is the manufacturer's. This site does not hold it.

## Components

Engine

## Vehicles listed

- 2025 to 2027 MACK PIONEER PR \(4\)

## Other bulletins for the same vehicles and component

- [CBR 2596 202608](/bulletins/11036585.md), 2026-09-01, Service bulletin: ENGINE; ELECTRICAL SYSTEM. The purpose of this CBR is to provide steps on how to correct a customer complaint of a no crank/engine start condition.
- [CBR\-2591\-1 202606](/bulletins/11034133.md), 2026-06-29, Service bulletin: ENGINE. The purpose of this CBR it to provide release notes for the recent Engine ECU software.
- [CBR\-2586\-1 202606](/bulletins/11034129.md), 2026-06-29, Service bulletin: ENGINE. The purpose of this CBR is to address issues of exhaust stack rotation on version 4 products.
- [CBR 2465\-6 202605](/bulletins/11033131.md), 2026-06-02, Service bulletin: ELECTRICAL SYSTEM; ENGINE. CBR to diagnosis issues with the Proactive Engine Restart system and Hood Open message.
- [S4757 022026](/bulletins/11029456.md), 2026-03-03, Service campaign: ENGINE. 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 202601](/bulletins/11028052.md), 2026-02-03, Service campaign: ENGINE. CBR MCO/VECI Label Reprint.
- [CBR 2522\-5 202601](/bulletins/11028047.md), 2026-02-03, Service bulletin: ENGINE. CBR \- Frequent Parked Regeneration Requests \- Models PR \(4\), AN \(4\).
- [CBR 2535 202512](/bulletins/11027011.md), 2026-01-05, Service bulletin: ENGINE. The purpose of this CBR is to address reports of regeneration failure when ambient temperature is below 30F.
- [CBR 2526\-4 202511](/bulletins/11026039.md), 2025-12-03, Service bulletin: ELECTRICAL SYSTEM; ENGINE. CBR \- Parking Heater Inoperative \- PR\(4\) \- AN \(4\).
- [CBR 2525\-2 202511](/bulletins/11026038.md), 2025-12-03, Service bulletin: ENGINE. CBR \- Exhaust Leak or Noise – Turbo Compound \(TC\) Bolt Inspection and Repair \- PR \(4\).

JSON: [/v1/bulletins/11036590](/v1/bulletins/11036590)

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