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Service bulletin FSB-255-023

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 id10044247
Published by NHTSA2012-05-24
Manufacturer's numberFSB-255-023
Manufacturer's date2012-04-01
NHTSA componentENGINE AND ENGINE COOLING:ENGINE

NHTSA's summary

MACK TRUCKS: SEVERE FRETTING DAMAGE OF THE ENGINE VARIABLE GEOMETRY TURBOCHARGER ACTUATOR (ENGINE VGT ACTUATOR) HARNESS AND TURBINE SHAFT SPEED SENSOR (TSS) CONNECTORS MAY CAUSE AN UNRELIABLE SIGNAL TO THE ENGINE VGT ACTUATOR. ALSO INCLUDED MODEL CMM AND CMH. NO MODEL YEARS GIVEN. *JS

The document

No address for NHTSA's copy can be built for this communication. Ask the dealer for it by the manufacturer's number.

Components

Engine

Vehicles listed
MACK CHU2006 to 2010
MACK CXU2006 to 2010
MACK GRANITE (GU)2012 to 2013
MACK GU2006 to 2011
MACK LEU2007 to 2012
MACK MRU2007 to 2012
MACK PINNACLE (CHU)2011 to 2012
MACK PINNACLE (CXU)2011 to 2012
MACK TD2012

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