I found a Service Bulletin that may (or may not) be applicable:
NUMBER: 18-014-11 REV. A
GROUP: Vehicle Performance
DATE: September 15, 2011
Flash: MIL Illumination P0401 - EGR System Performance
This bulletin involves selectively erasing and reprogramming the Powertrain Control
Module (PCM) with new software.
**2009 - 2011** (KA) Nitro
**2009 - 2011** (KK) Liberty
NOTE: This bulletin applies to models equipped with a 3.7L engine (sales code EKG)
and an automatic transmission (DGV) built before February 23, 2011 (MDH
Some customers may complain of MIL illumination. No other symptoms will be noted or
experienced. Further investigation by the technician may find DTC P0401 - EGR System
Performance is set.
Jeep Social Care Specialist