OldNavy can no doubt chime in with authority on this, but you should visit L.O.S.T.
, the KJ forum, and peruse the CRD section on mods. There is a very simple one called the "Off-Road Mod" or ORM. I think it involves merely unplugging the harness connector to the EGR valve. It sets the MIL, and a code (of course!) but a bit of electrical tape over the offending icon lamp will solve it. It seems a poor way of addressing a chronic problem, however.
So far I've had no EGR trouble with my WK CRD (knock on wood). The KJ's were pre-DPF era diesels, and are typically lubed with oils containing high ash and phosphorus. The new, low-SAPS synthetics required on the WK CRD should help alleviate this problem.
Or so I hope!