Should car be running when checking codes?
Should car be running when checking codes? Always turn the ignition on or have the car running according to the instructions in the manual. Failure to do this might corrupt the scanning software. It's also very important that you drive around with the manual for the specific scanner model that you're using. How to read Trouble Codes on 88-95 GM cars and trucks? To read the trouble codes when your check engine light comes on on one of these old cars, you just need to put a paperclip in between two terminals, and then turn the ignition on, and the...