Bubba91

I wasn't able to use my scanner. When I plugged it in, it would say "no data at ALDL". I changed out the ECM and checked all of the pins and connections, but it turned out that the cigarette lighter fuse was blown. I tried to use my jump box to power the scanner and it had power, but couldn't read the data. I fixed the cigarette lighter fuse and then used that to power the scanner. That fixed it. I don't know why the cigarette lighter needs to be working in orde to read the ECM, but it does.

Crzyfrlss1

A lot of GM cars and trucks are like that, don't know why they made it that way.

Bump for a good and often forgotten tip.

pcolt94

All scanners need power to operate an it's usually 12 volts. It needs to get power from some place to operate the scanner electronics.

With some ALDL connectors the 12 volts does not mate up with the scanner power in and requires external power. My Tech 1 needs external power to run which is OBD1. With the onset of OBD2 and things got standardized, 12 volts power was utilized at the ALDL connector for the scanner. So with all the new consumer scanners designed for OBD2, no external power is necessary.

Bubba91

I had power to it via a jump box that supplies 12 volt power and it did power up the scanner, just wouldn't read the data. I then used the cigarette lighter and it worked. Tried it again w/ the jump box and it didn't work. The cigarette lighter has to be working for some reason.