i replaced my thermostat and now my pcm relay is chattering and the engine wont start. why is my relay chattering?
PCM is not a relay - its the engine control computer - aka ECU, ECM Powertrain Control Module - PCM. Chattering? Did you mean positive crankcase ventilation (PCV)?
Search Honda Civic Coupe Questions
Are you a UK consumer? CarGurus now has a discussion forum in the UK.
Honda Civic Coupe Experts