Yes it the oxygen sensor . There are 2 of them one upstrean & one down stream passed the catalitic converter. Te up stream is the most important. The code should say which one. Get it replace as soon as you can. It can effect GAS milage & other things. I think if the up steam is bad, it can destroy your CAT. Replace it with ONLY a factory MOPAR OEM one. After market O2 sensors do not work very well in Grands.
ZJ 98 5.9 LTD. Lots of mods. 7" T&T's Long Arm Lift ,BFG KM2"s,35X12.50x16's,4:56's, Vanco brake upgrade, M1intake,Holley52mmTB,MikeLeach Headers,, Arb'ed HP D30,Aussie Locked rear,Procomp MX6 Shocks,Arb front,RearTR bumpers,ECT.ECT.