Cummins and IC Corp. have identified an issue with the DEF/QLS on certain Cummins engines. Due to a supply chain issue, parts are not readily available for proper repair.

NYSDOT has been made aware of a software update that can be performed as a temporary repair until parts are available.

Jeff Corey, Field Operations Manager, Bus Inspection Program, with NYSDOT has notified NYSBCA the following regarding the Cummins DEF QLS Issue.

Cummins and IC Corp. have identified an issue with the DEF/QSL sensor and replacement parts are unavailable at this time. Please see attached guidance on how to proceed with inspections for these vehicles and pass this information onto all MVIs.

As of this date, Blue Bird Corp. will not allow any DEF software updates on their vehicles. If I receive any information from other manufacturers I will pass it along.

Click below on the attachments.

DOTMemo-CumminsDEF-QLS

ICLetter-DEF

Cummings-DEFStatement

Decal-DEFGaugeInoperative