As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
PROX SYSTEM FAULT CAUTION MESSAGE IN FLIGHT / INTERROGATED MDC FOUND B1 CODE: 007191. TROUBLESHOT IAW CRJ 900 FIM 32-32-10-810-A01. REMOVED AND REPLACED LANDING GEAR SELECTOR VALVE IAW CRJ 900 AMM 32-32-10-000/400-801. OPS CHECK GOOD AT THIS TIME.