I have a 2006 Saturn ion. I am having to replace the ecu. I got one from a junk yard from the same model and year. do I have to reprogram it

Check and clean your positive terminal and connecting lugs as corrosion can 'brown out' the brain and give the impression that it is at fault. Clean all connections to your battery and accessories...and negative ground battery and connecting lugs. Then we'll talk. Already experienced this difficulty as a professional mechanic. Was expensive then, even with used ECU's (which cannot be returned, btw). just a simple damn battery top cleaning...oy vey-

thanks bob. Did all that and hooked up to computer and the relay was telling it to crank but the ecu was not responding. And the only time It wont crank is when the ecu gets warm. After letting it cool down it will crank and start but then randomly shuts down. I bought the ecu witch had been tested at the junk yard. I didnt know if it had to be reprogrammed before i installed it or if it would mess anything up if i didnt

I confess doug, I know nothing about saturn other than a GM attempt to compete with toyota. American electronics...sorry, haven't a clue. wish I could help. Aside from gozinta and comezata problems, I'm rather at a loss...

There has to be a pulsing crank sensor...you seem to be on the right track. Take it to a component level rather than stepping back from the automotive masterpiece.

is it...yes it is, a Crank Angle Sensor. Replace yours today!

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i had my themstart replace and they got water on the crankshift now my car is having a hard time starting. it acts like the starter is draging. it is a 2006 staurn ion redline