Error code PO492 on my 2006 xj8l

Hi all: Replaced my radiator and auxilary heater pump and somehow mucked up something because I now have PO492 error code and its starts well but withing 60 seconds idles rough. code says insufficientflow to bank 2?
Dennis Cunningham
2006 xj8l 84,000 miles
2003 VDP 104,000
1986 xjsc 53,000 miles