What was found
PDX - SMOKE AFT LAVATORY MESSAGE, MASTER WARNING, AFTER TAKEOFF. PERFORMED CHECKLIST AND PULLED APPLICABLE CB'S. RETURNED TO FIELD, NO FURTHER PROBLEMS NOTED. INSPECTED A/C, NOTICED STRONG ODOR OF SOAP IN CABIN BLEED SYS GROUND RAN IAW TASK 72-00-00-100-801 PAR H STEP 25. OP CHECK GOOD, NO DEFECTS NOTED. NOTE: ACFT ENGINES NR 1 AND NR 2 HAD PRESSURE WASH THE NIGHT BEFORE. RETURNED TO SERVICE. NO PARTS REPLACED.