You haven't specified the model but on a '03 onwards Megane the connector is located behind the small panel at the bottom of the centre colsole. There is a little handle you can pull it out with..
The hookup is usually under the dashbord close to the steering column. If it is not in plain view, it will be under a removable panel approximately 4 or 5 inches by 6 or 8 inches,
You can run a diagnostic test for the knock sensor, on your 2005 Chevy avalanche, by hooking the engine up to a diagnostic tester.
Sure can...hook it up to a diagnostic and it should bring up a code telling you that the sensor is out.
right underneath the steering wheel
hook the ground wire to a good ground and pierce the wire you want to check with the tester, if it lights up, it has power, if not it doesnt.
On the 2002, mine is under the ashtray. Simply lift up and out the whole ashtray and there it is
Generally the location of the OBD-II diagnostic port connector is under the drivers side dashboard. It may be integrated into the lower portion of the dash, with a cover over it which you can remove and access the connection point.
The easiest and most accurate way to check the fuel pressure, on your 2001 Chrysler Town and Country is to use a diagnostic tester. The diagnostic tester will tell you the exact fuel pressure at various RPMs.
Get a shop with the appropriate software for your engine to hook it up and do a diagnostic on it.
You have to hook up an OBD scanner to it. Most auto parts chains have one available, and can run a code diagnostic for free.
chances are you will have to take car to dealer or mechanic to have them hook up a diagnostic machine to the cars computer
Stop by your local AutoZone. They will hook it up to a handheld tester and print out which oxygen sensor is failing.