Quote:
Originally Posted by Cloud
I received the same diagnosis and suggest for a fix from two different places, and went with that, but I knew there was a chance that it wouldn't fix the problem.
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They simply followed a simplistic diagnostic chart. It says if the valve clicks when voltage is applied, then replace the computer.
Well, an idle air control valve actually opens and closes quickly per commands from the computer. So quickly as to need an oscilloscope to actually see it. Computer monitors how fast the valve is responding. If the response is not what was ordered, then the computer flags a check engine code. If the valve works normally but too slow, then computer gets replaced (if only following the diagnostic chart). Valve can be sticky, partially clogged, etc. and still pass the on-off test.
The entire circuit is real simple. Computer tells valve to open and close rapidly. Valve opens and closes rapidly. If valve does not do that fast enough, then an error code is created. Only three things in that circuit - computer, wire, and valve.
How I would have responded? I would have asked why they knew the computer was defective. I never mention the IACV. Let them mention the valve and why they know the $200 valve is not defective. I have found only some mechanics who really know their stuff because the word why is used heavily. The stuff I do not know then gets confirmed later with an internet search.
If anyone tells me something without the reasons why and without numbers, then he is lying.
Standing in the dealer to get a new oil filter or wiper blades is very educational. Watching them talk to women quickly separates honest dealers from the shady ones. Numbers (verses no numbers) quickly identifies the honest ones.