As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
IAD/BWI - FLT 6233 - DURING TAXI AT 1555 HRS ON 7-17-97, RETURNED TO GATE DUE TO GPWS FAILED ON TAXI. AIRCRAFT RETURNED TO GATE WITH NO FURTHER PROBLEMS. MAINTENANCE INSPECTED AND RECYCLED AVIONICS MASTER, OPS CHECK OK. AIRCRAFT WAS RELEASED AND APPROVED FOR RETURN TO SERVICE. (X)