Subject: Immobilizer 2001 Eclipse Spyder
Question:

I have a 2001 Eclipse Spyder. About 2 weeks ago I lost power (battery cell
leaked). I bought a new battery and now the car won't start. I plugged in my
diag. tool and get a P1603 error. Backup battery circuit malfunction. When I
put my key into the ignition all i get is a winding sound and the car alarm
going off. Has the immobilizer been tripped? If so how do I either bypass or
clear this error. Do I need to reprogram the Computer? ANY input from
anyone would be helpful
Answer: Jarrod,
Verify the new battery is oriented properly. It's real easy to accidentally install the battery backwards. That can blow out most of the sensitive electronics in your car. The code you're getting sounds like the backup system, that still allows the alarm to be active even if the main battery circuit is disturbed, could have been damaged some how. There's nothing I could really recommend you try without actually testing your charging system. Check your owners manual to see if there is a procedure you need to follow after a new battery is installed. You may even have luck calling the service department at your local Mistu. dealership to see if there is a procedure.

If you cannot find any information from your manual or from the dealership, you may need to have your car towed to a mechanic to further diagnose your charging system.
Good luck!