if you are getting a TDC sensor error for sure, the things to check in order
timing belt for stretch
timing belt tensioner bearing and spring
camshaft position sensor
crankshaft position sensor
Whenever a TDC sensor issue arises in a distributorless Civic whose timing belt has also not been changed, I put in hardware along with 2 new sensors - They are painfully hard to extract from the engine - requiring removal of the crank pulley, timing belt covers etc.
Get it scanned and replace parts as necessary - its not a very complicated job, just very involved.
