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Service bulletin TSB230168

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 id11036019
Published by NHTSA2026-08-07
Manufacturer's numberTSB230168
Manufacturer's date2026-07-07
NHTSA componentENGINE

NHTSA's summary

This Technical Service Bulletin describes the verification and resolution steps for the engine control module calibration of certain B6.7 engines in Hybrid Transit and School Bus applications which may falsely detect an issue with the engine cooling system when ambient conditions are below 4 °C and auxiliary heating systems affect coolant temperatures , resulting in fault code 3243 being set. This is an update to a previously submitted communication.

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
CUMMINS B6.7

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