I am not sure if this is anything to worry about, but I have situation where my CEL comes on with a P0400 code. This is related to the ERG system, but after having it checked out by the dealer with no conclusion he cleared the code, charged me $70.00 and sent me on my way. Well needless to it came back and again was a P0400 code. I paid no attention to knowing what is was but then it cleared on its own, then it came back, then is cleared on its own, then came back, then cleared?.currently out.
This all started when I hit a tire tread on the interstate at 65 mph and worked its way under the car smashing in the panel protecting the drive shaft at the rear part. No real damage, but I know the O2 sensor is located at the front the shaft. I know this may sound strange but it cleared after the oil was changed, then just yesterday after I filled up with gas..I know these have nothing to do with each other, but trying to give an much information as possible.
Anyway, are their any thoughts as what to do, other than giving an deal huge sums of money to resolve since there are lots are places to look.