Why clear codes???
Why clear codes???
Lead Driver
Joined: Feb 2003
Posts: 8,140
Likes: 4
From: Oak Harbor, OH
With some older vehicles the codes can prevent new ones from showing. With OBD-I if there are any codes, stored or new it jumps into "limp home" mode, which usually makes the engine run full rich. This can foul spark plugs, and almost always toats the O2 sensor(s). It also takes the fuel mileage WAY down, usually by 4 to 5 mpg.
