As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ON FLIGHT 4064, CREW REPORTED THAT ON APPROACH TO ORD ELECTRICAL FUMES IN COCKPIT. EMERGENCY DECLARED. AIRCRAFT LANDED WITH OUT INCIDENT. AIRCRAFT REMOVED FROM SERVICE. COULD NOT ISOLATE PROBLEM AT THIS TIME. A/C DID 2510 CHECK FLIGHT AND PASSED. AIRCRAFT RETURNED TO SERVICE.