As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
SHIP 3768 -PRESS- ON DESCENT INTO DEN PASSING THROUGH 20K FT CABIN PRESSURIZATION AUTO FAIL LIGHT ILLUMINATED. LOST CABIN PRESSURE AND PASSENGER O2 MASKS DEPLOYED. CORRECTIVE ACTION: PERFORMED CPC-1 /-2 BITE CHECK. BOTH IDENTIFIED OFV FAILURE RECORDED. REPLACED OFV PER B737 AMM. SYSTEM OPS CHECKS GOOD. MANUAL AND AUTO MODE TEST GOOD. AIRCRAFT RETURNED TO SERVICE.