What was found
AIRCRAFT WAS GROUNDED: AN EMERGENCY WAS DECLARED DUE TO: FUEL IMBALANCE 2,000 LBS WITH NORMAL LANDING; AIRCRAFT AIR INTERRUPTED BACK TO AND LANDED SAFELY AT ORD. AFTER DEBRIEFING OF FLIGHT CREW DISCOVERED CROSSFEED VALVE WAS LEFT OPEN. ACCOMPLISHED FUEL IMBALANCE EXCEEDANCE CONDITIONAL INSPECTION, PER AMM 05-51-48. ALL OK AND NO EXCEEDANCES. ACCOMPLISHED CROSSFEED VALVE OPERATIONAL TEST, PER AMM 28-22-21 AND ENGINE FUEL FEED PUMPS FUNCTIONAL TEST, PER AMM 28-22-00. ALL CHECKS GOOD WITH NO DISCREPANCIES NOTED.