Pick up a diagnostic scanner recently and did some testing to try the thing out. I have a 1991 300 E with a 16 pole diagnostic socket. My first question; Are all the poles of the socket used. In running through the tests, it appears that only 5 of the 16 were snug when I plugged the test lead into them. They were #'s: 1 Ground,3 CIS-E,6 SRS/AB,7 A/C and 14 EA . Is this correct?? I am assuming that systems associated with the other pins, I do not have in my car. However, I thought that #8 pin for the Distributor Ignition would be one in use. Any insight would be greatly appreciated.

Now for my second question: I received troubel codes of #5 Oxygen sensor (Signal illogical): #16 EGR Valve (switch over valve open or short circuit): & #29 Difference in coolant temps between CIS-E unit and EZL Unit. Again any insight would be appreciated. I know that these codes do not necessarily mean that the items themselves are defective, but only that there is a problem in that circuit or system. The car just turned 100K and runs fine.

Thanks