My stepdaughter has a 2001 Bonneville. It has some issues. We have read the codes and found MAF, O2 and a cylinder 3 misfire. I replaced the MAF, with no avail. With the misfire I figured the easiest to do was swap two of the coil packs around. Ever since than the scan tool will not read. I have check the cigarette lighter fuse and the ECM fuse. I have now checked every fuse, even the block under the back seat, with my multi-tester. Is there any other reason for the scan tool not to read or acknowledge the vehicle. I am trying to help her get her car ready to move this summer. Neither one us has much for $, so I try to do as much as I can myself. Any assistance would be greatly appreciated. Thank You, Scott.

Verify on another vehicle if the scanner works.

Thanx Mike. The scanner is a Bosch unit from our local Oreilly'*. I'm sure if there was any issue with the unit, it would have been fixed. I will go tomorrow morning and see if it reads my truck (2001 Tahoe). The scanner would not even acknowledge her car. Is there any reason why swapping the coil packs would make a difference? When I first logged on, I forgot to sign in and there was a video for a scanner called Fixd. Did you leave that thread?

Swapping coil packs should have nothing to do with the scan tool.....

Make sure you have bat voltage at pin 16, and ground at 4 and 5....