Posted: Sep 09 2012 at 12:44pm | IP Logged

You have to follow this one closely.  2008 frontier, 6 cyl, auto trans, 46,000miles

Service engine light came on periodically. Then i began to notice that it was engine temp related . I think. Engine temp starting at cold and advancing to normal engine running temp servic engine light doesn't come on no matter how long or far i drive. However,  when i stop for awhile and the engine temp cools down to a point and i start to drive again service engine light comes on and stays on. If i stop for a long time  for the temp to go back to cold and drive  the service engine does not come on. I had a comp read out when the service engine light was on. It registered P0603 ecm power supply circuit.  Prob cause open or short circuit or faulty ECM.  Dont see any relation to the problem.  Did have a new battery put in. Did not fix the problem. Any similiar problems or some expert suggestions as to a fix or what is wrong?  Immiadiate prob is MD emission inspection sta wont do analysis with an engine light on>. Where is the ecm control unit and is it hard to replce if this is the problem?

thanks in advance