After I cleaned my throttle body...every time I start the car the engine light comes on. When I go to check which code it is ...the light will not come on.
If I put the key in and immediately turn the ignition to start the car...the light WILL come on.
If I turn the key to the second position, wait a second or two and then start the car, the light WON'T come on, but may come on after a half hour or so of driving(not always tho)


Any ideas what's going on?
Will the diagnostic procedure work with the check engine light off?
Can it be done with the car running because that's the only time the light is on?

Thanks,
Josh

 

You should be able to pull the code whether the CEL is on or off (i.e. whether it detects an error or not).

If there is no problem, the CEL will flash "505" in diagnostic mode one. If the light is going on and off intermittently when you are driving, then that is a sign of a real problem. Generally a false error will lead to the light coming on, then turning off after a few start cycles. Pull the code and look up the result in the stickies above.

 

Do the procedure to get the codes. More than likely, it will flash out regardless of whether it is there currently. I don't think an intermittent CEL is necessarily bad. I believe a CEL that flashes is supposed to indicate a problem that needs immediate attention.