As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
WHEN PERFORMING IDLE POWER TEST ON #2 ENGINE START VALVE LIGHT REMAINED ON AND BLINKED. GROUNDED - YES. REMOVED AND REPLACED #2 ENG STARTER VLV REF B737-800 AMM TASK 80-11-03/401. START VALVE TEST AND TEST #1 (PNEUMATIC LEAK CHECK) FROM POWER PLANT TEST REFERENCE TABLE BOTH GOOD. WHEN PERFORMING IDLE POWER TEST ON #2 ENGINE, START VALVE LIGHT DID NOT REMAIN ON. OK FOR SERVICE.