As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DISPLAY SOURCE 2 INDICATION RAN CHECKLIST. GROUNDED - YES. VERIFIED NO DEU-2 DATA DEU FAILED MSSG 31-67081. REPLACED #2 DEU WITH SERVICEABLE ONE REF B737-900 AMM 31-62-21/401. ALL SOFTWARE AND TESTING ARE UPDATED AND PASSING. DEU REPLACEMENT LRU LLM TEST PERFORMED AND PASS.