Ive got an idle I cannot fix and I really think its the computer being worn... I have an extra computer that I found for cheap so Im wondering why I don't put it in to try it out. What is involved with replaceing the computer? Is it turn off the car and switch out the computer? or Is it more involved than that? Any help is appreciated...

 

Turn off the car, unhook the battery, unplug old and re-plug new.

 

Yeah, the computers an easy switch, but I will say that my car has a weird idle i can't get right...and my computer is brand new...not reman, if you get the comp cheap its worth it, but it could still be many other things.

 

What do you mean a "wierd" idle? Is it oscillating, or hunting? Too high, too low? Replacing the computer just because you have an idle problem is just nonsense.

 

I'm not going to replace the computer yet. Ive got 3 codes, 411 and 412 saysing idle is too high and too low, and a code 116 which is ECT out of range.

I think the coolants temp being so low, the computer ups the idle to prevent damage too it. Ive replaced the ECT sensor with no luck and I got voltage from the computer to the sensor in the harness, Im not sure what else it could be.

 

There are certain proceedures, with a breakout box, that you perform to see if the computer is indeed bad. Have you checked the wiring for the ECT, I wasn't clear on that.

 

No I haven't. How can I check that and make sure the comp is ok?

 

I'm not in school anymore or at work so I can't look up the proceedures at thia time. What it involves is testing the resistance of the harness for the ECT. Because how the ECT works is with the computer reading high resistance, it thinks that it's cold. Thus, if there's unwanted restistance in the wires for the ECT, it'll want to keep it at a high idle.

Testing the PCM is a whole different story. It involves having a breakout box that installs temporarily between the PCM and thw whole PCM wiring harness. This breakout box has a whole bunch of numbered pin that represent the pins on the connector for the PCM. This allows you to safely check the resistance of certain components in the PCM. 99.99% of the time, it's a harness problem.

Just for the hell of it, what kind of shape is your battery in? Having a bad battery can make computers go nuts. And overlooking that can solve some problems.

 

Well Ill keep at it a few more days and if it doesn't work out ill let the dealershi handle it I guess.

My battery kinda sucks its got corrrosion but I got rid of most of it mixing water with baking powder and letting that soak through it... Could that honestly be the problem? Everything is fine elctrically and I don't want to by a battery if theres no sense in it...

 

...Or you could try a known good one for the time being, just to eliminate it from the equation.