As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ORD - CREW REPORTED STRONG ACRID ODOR IN CABIN ON TAKEOFF THEN SAME ODOR DURING DESCENT. FLIGHT LANDED ORD WITHOUT INCIDENT. AIRCRAFT REMOVED FROM SERVICE. REPLACED BOTH PRESSURE REGULATING SHUT-OFF VALVES. SYSTEM GROUND CHECK NORMAL OPERATION.