Originally Posted by PaDawg
My check engine light came on at 2000miles, took to MB dealer they replaced a faulty emission sensor. The light went out before the sensor arrived at the dealer but they replaced it anyway. At 6150 miles and 2 months later the light has reappeared! RV dealer suggested we cycle the ignition several times to allow the system to reset? Any thoughts??
dealer is full of it.dis-connecting the battery may reset it. cycling the key will do nothing. depending on what kind of chassis you have it could be a code that will only erase by scan tool. other than that it may take 50 ignition/run cycles or 50 engine coolant and ambient air equalization cycles (sits over night 50 times) you have an issue and as long as it isn't a P0442 small evap leak detected (many times a loose gas cap or cracked gas cap seal but a myriad of other small evap leaks The first two are just the most popular) they are wrong. have them check it again, and fix it right. some O2 heater ckts will intermittently do this. there are a few that must meet acceptance criteria of speed temp and duration, and these can take hundreds of miles under certain conditions to do so. they are very tough to diagnose as well.
I will admit CEL can be a pain to diagnose but it aint gonna fix it self. there are a few that are driver induced by over filling the fuel tank and putting it in park before the computer sees zero speed sensor signal but these are unlikely your problem.
you may want too invest in a cheap generic scan tool so you can 1. know what code is stored and document ans 2. erase it if it is a recurring intermittent code.