Geo Metro 1994 46

Answer 1

Code 46 is the trouble code for the Idle Speed Controller which is that big black box thingy on your throttle body. A lot of Chilton-type manual books omit that code because the ISC isn't found on pre 94 Metros. The ISC is a computer controlled auto-adjuster for the engine idle. An important note: code 46 is often caused by misadjusted distributor timing. As you probably know, timing affects the idle, and if improper timing moves the idle beyond the ISC's adjustment range, the check engine light will come on and diagnostics will return code 46.