Bad Computer

2002 MITSUBISHI DIAMANTE
171,000 MILES • 3.5L • V6 • FWD • AUTOMATIC
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ERIC5735
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I have a bad computer can I buy a used computer from an 100 percent positive eBay used parts and get a mechanic to install it and program the used computer because of the transponder on key? Or do I need to go out and buy a new computer for mechanic to install?
Mar 29, 2017 at 10:51 PM
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STEVE W.
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What makes you think the ECM is bad?

As for the part. Talk to the shop you plan to use about it. Some will not use a "used" ECM because it is way to easy for it to be bad. Others do not have a problem but wont offer any type of warranty. Be sure that they can program it as well. Some vehicle makes can only be programmed by a dealer when it is a security item like the key.



Mar 30, 2017 at 1:18 AM
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ERIC5735
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Had car Diagnose by electrians told me computer is no good and my vent solenoid needs to be replaced and to fix problem mechanic said labor plus parts would be 890 to fix
Mar 30, 2017 at 12:44 PM
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STEVE W.
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OK Vent solenoid would be for an EVAP leak. I take it the check engine light came on!

What is your car doing/not doing. I'd hate to see you replace the ECM if it's something like a bad ignition switch or bad transponder antenna or similar.
Not saying the mechanic is wrong, just don't like seeing people spend money for the wrong part.
Mar 30, 2017 at 2:48 PM
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ERIC5735
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Yes check engine light is on car is hesitating during idle and while I drive I have an ob2 Bluetooth reader it said I had misfire on cylinder 3 that's what I original took it in for they told me computer is bad and I need to replace vent solenoid
Apr 3, 2017 at 3:49 PM
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ERIC5735
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Car turns on normally just a little hesitant, gears shift okay, car doesnt rev like it should hesitant
Apr 3, 2017 at 4:03 PM
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STEVE W.
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Vent solenoid isn't that bad to change. Misfires can be caused by many things, plugs, bad wires, cap/rotor, bad injector, bad wire to the injector.

Easy to test the signal that turns on the injector. You need a simple test light called a noid light. Unplug the injector plug in the noid light and start the engine.
If the light is flashing the ECM is probably OK and the issue is with the injector or the ignition on that cylinder.
Apr 3, 2017 at 9:49 PM
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ERIC5735
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Mechanic did noid light test on injectors already,misfire apparently are being cause by bad computer
Apr 7, 2017 at 9:18 AM
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STEVE W.
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In that case you need an ECM. You don't have to buy a new one, you just need to reset the security features to match your vehicles system.

Just be sure that the part numbers are the same.
MR578512 if you don't have traction control.
MR578513 if you do

You might want to check your heater core. There are notes about ECM failure because of the core leaking and getting to the connectors and inside the unit.

Apr 7, 2017 at 8:51 PM