Hi there, recently my brother put my battery in my geo metro backwards ( having the best intentions) as I’m sure you know this blew quite a few fuses, I have also changed the computer, the cluster , all the relays , the ECM module & I still have the battery and check engine light on
The car does run ( ok) I have tried the diagnostic port but all I’m getting is the green shift light flickering fast
Any ideas I really want the car back to where it was before
Dave
What year is this car?
I’d use a voltmeter to measure charging voltage at idle. Should be around 14V
it sounds like the battery is not getting charged
If I were you, I’d have that battery tested
You might have blown the fusible link for the alternator, or the maxi fuse
In fact, the low charging voltage might be the root cause of the weird problems you’re now having
It’s a 95 geo metro
I checked the charging it’s right at 14v at idle
Where is that fuse able link located , thank you so much for the help
I did not mention I have also replaced the alternator , the starter, and the battery
Although I don’t think any of them are bad 
The fusible link is the heavy wire that runs from the alternator to the battery.
But because you have 14 volts at the battery at idle…I doubt that it is a problem.
Yosemite
Agreed, it sounds like your battery is being charged just fine
Thanks for checking the charging voltage
Just a thought but sometimes it takes a few starts and drives before the check engine light resets. Could that explain some of this?
Have you checked evey fuse. Have you read the code? Here is the procedure. http://www.robietherobot.com/metro/errorcodes.htm