[ale] OT: check light diagnostic tool

[Michael B. Trausch]

On 06/12/2013 10:50 AM, Michael H. Warfield wrote:
> I think
> you still have to drive a certain number of miles, after resetting a
> check light, before you can run an emissions test though, if that's the
> reason for your request.

After clearing all trouble codes from the computer, you have to drive
"enough" (vaguely defined; for GM, usually three or so "drive cycles"
per their testing procedure) to ensure that the computer reports "OBD
Readiness".  Once the computer reports that it is verified OBD readiness
for all of its supported categories, it can pass an emissions test. 
Also, it's possible to have "pending" codes; for example, P030x is
usually a "pending" code until the event has been detected more than X
number of times per Y interval, to account for the fact that engines can
have isolated misfire events that have no significant meaning and do not
have a drastic effect on emissions (an older engine can easily misfire
occassionally under high load, such as climbing a mountain with a
trailer and a full family...).  Pending codes, however, do not affect
OBD Readiness, IIRC, nor do they turn on the MIL.

    --- Mike

-- 
Naunet Corporation Logo 	Michael B. Trausch

President, *Naunet Corporation*
? (678) 287-0693 x130 or (888) 494-5810 x130

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