05 aveo engine and hold light flashing

[2005aveo]

avguy, plugs and wires were changed about 3 months ago for a tune up because it was running rough. The light was not on when those were changed at the time. Can the ODB code be checked without the Hold light being on. This activity is random. Today I started it and it ran fine, but yesterday I started and it started rough and the Hold light was flashing.
Thanks for your help!

[avguy]

Normally the check engine light being on will mean that a code has been set, but you should try to have it read now anyway. Autozone, and many of the other parts stores will scan for free, and sometimes even offer helpful advice about the problem.
Did installing the new plugs and wires eliminate the problem for some period of time? I understand this is random, but it may be important to know if the new parts helped, even if it was only for a short period of time. Random problems can be very hard to diagnose and misfire can be caused by a number of things, which is why it's important to provide every piece of related information that you have.

[2005aveo]

Sorry it took so long for me to get back to this. I went to Autozone and they wouldnt check it without the engine light on, so I had to wait for the engine light to come on. After it flashing along with the Hold light, the engine light just stayed on for the last week. I went to Autozone and they were able to read the codes. Codes: P0300 - Random misfire and P2610 - PCM/ECM internal failure. They told me that I needed a new ECM. If I get one from the salvage yard with the same properties (Automatic Tran, air conditioning,) do I need to get it flashed by a dealer? Or is that something I can do on my own?

Thanks.

[avguy]

No personal experience with that P2610 code, but the book says to check the power supply before replacing the ECM. So that means checking fuses and swapping relays; checking for corrosion on the fuse box connections, the battery wires and connections; checking grounds; and doing a load test on the battery. Some of these problems can be hard to find, such as when a battery cable is breaking down but hidden from view under the insulation. Sometimes pushing around wires while the vehicle is running (or trying to start) can flush out bad wires or connections. Another flavor of this is running or trying to start at night with no lights on, looking for arching. Spraying a bit of misted water onto the wires in darkness is another trick to help diagnose wiring problems.

Regarding an ECM replacement, the online parts outfits say that they always program their ECMs. OTOH you can find reports of guys swapping a used computer into various vehicles and having that work fine without reprogramming. But there are also stories of this not working out for other folks. So this is definitely a case of YMMV. The parts guys are selling them for somewhere around $250, so if you can find one at a boneyard, and the price is low enough for you to roll the dice, then by all means give it a shot.

[2005aveo]

Thanks for all your help....
Well all my problems was a blown head gasket !!!! Got new gasket and car runs great!!!! No more flashing lights check engine light off.. it was crazy how sometimes it would run great and sometimes not....... all the codes that would come up... hope this helps someone.......