Engine light on. Does not seem to affect operation. Error codes p1009 and p0128. Any clues to problem? 2005 honda accord 4 cyl.

P1009--Variable Timing Control issue. There's a Honda Service Bulletin covering this problem (PCM update).

P0128--Coolant system malfunction. Possible causes:

- Leaking or stuck open thermostat--only use 50/50 mixture of proper antifreeze and distilled water.
- Low engine coolant level
- Insufficient warm up time
- Faulty engine coolant temperature sensor
- Engine coolant temperature sensor harness is open or shorted
- Engine coolant temperature sensor circuit poor electrical connection