How do i pull the trouble codes from the ECU.

2004 Civic LX 1.7

 

Bring your car to AutoZone where they will retrieve the code free of charge. Alternatively, purchase an inexpensive OBDII scan tool.

 

If you find more than one code, don't replace any parts yet. Clear all the codes and then drive until the CEL comes on again. Then read the codes again. The code(s) that reoccur are more likely to correspond to real problems. Sometimes a code is set for a reason that resolves itself, but it stays stored for a long time.