Automotive Forums  Where Car Enthusiasts Go to Discuss Cars Online

I have a 2001 mitsubishi galant. it has got 121K miles but it runs perfectly smooth although some time when i slows down in my apartment area or trfiic light it stalls. My SES light is also on for last couple of months.I recently coded my car and got the error code P0506(Idle Control System RPM Lower Than Expected). The throttle body is clean and the mechanic said i need to replace the IAC motor(costs 350+service). he is not giving gurantee that after changing the IAC motor whether the SES light will go off or not. He is saying if that does not work may be i need to change my entire computer system. Both the IAC and computer system(costs 1300+charge) are too too costly and i have no money as a student to spend on.mechanic also told me that if i am not changing the IAC motor soon it may entirely burn the computer system and i may need to change the rebuild the entire computer system also.can anyone honestly suggest me what needs to be done. what are the test i need to do to find out what exactly needs to be changed??i just want to keep this car for next 2yrs and not in a state to sell and go for a mew one.is my car in the last stage??please help.  

That price for the IAC motor is about right, but you could probably get one for half that (or less) from a junkyard, and you *should* be able to put it on with relatively few tools.

You say the mechanic won't guarantee that a new IAC will fix the problem - did you pay for diagnostic work (or did they just pull the code)?  If not, then he's perfectly correct to not guarantee it; it could very well be a wiring or PCM driver issue.

Unless you have a scan tool, DMM & wiring guides, there are no tests you can do yourself.  Depending upon what the failure is or how it has failed, there is the possibility that it could damage the computer, especially if the driving mechanism develops a short.

If the motor runs fine as it is, it's probably not on it's 'last legs' - however if you're in the habit of running your engine for months without checking why your SES light is on, your engine will not last as long as it should.  Service Engine Soon is NOT a suggestion.