06-22-2012, 06:11 AM
Join Date: Apr 2008
If you've got a burned chip like I did in the ECU, and that was caused by external component failures or vice-versa, it is the luck of the draw.
In my case, the flaming chip did not destroy the circuit board traces around it.
I was also lucky that I've been in the repair industry for defense, avionics, down to automotive and consumer devices and had the skills and equipment to replace the idle air control valve chip.
The really scary thing on these cars is one component can destroy another one, so you really have to diagnose it.
In my car in addition to the idloe air control valve stepper motor shorting and burning out the (non current protected) controller chip in the CPU, it looks like the chip in the ECU can fail and burn out the valve. Load of crap design...
Also some have had the smart engine mount controller chip fail due to the engine mount shorting, and that chip is near the idle control chip, burning it out with collateral friendly fire.
I haven't been on here in awhile, but this forum saved me close to 2500.00 for this incident. Not counting if brought it to a dealer that might not even have known of this congenital problem at the time.
If you are going to dig into it, here are some steps you can take off the top of my head. Others will jump in for details I presume, as I may not be around.
Check for motor mount problems also, but:
Measure the resistance of the "idle air control valve" motor, two or four windings, , probably 2 center-tapped, I forget. they should read some low value of ohms, I think 4 or so. One of mine was a dead short. Use good meter, and/or a friend who knows some electronics.
Retrieve the computer, was hard for me before really knowing where it was: Think of it resting on the hump, as far forward to the firewall as possible, in your radio stack trim. Then I think I needed right angle screwdriver or nutdriver to get at the mounting bolts. I think they were normal hex/phillips screws, nothing special.
Open the top of the computer in a static safe way, at least not on your lap with a fuzzy sweater on....
Look at the (single in-line package) IC chips, if burned or popped, you should not miss it.
If the valve checks out good, and the chips look good, then maybe you are lucky, and it is something simple.
Any are encouraged to hijack this thread, I don't know when I'll be around..
PS, if you replace the computer, I think you have to jump hoops for getting the anti-theft reset, etc. I didn't as I replaced the chip in my existing unit.