It drains the battery down to around 11.5 volts overnight to where the car won't start. The current draw is 75mA at 11.5v. This current draw is consistent every time this happens.

While monitoring the drain, I have turned on/off everything I can think of including open/closing doors, trunk, a/c, etc. These all increase the load when they are on so that rules them out.

With the battery removed, there is no measurable resistance between the cables which tells me the load is not resistive. This tells me it is the ECU. After charging the battery overnight and putting it back in, the load is gone which also tells me it is the computer because this is resetting the computer.

Anyone seen this before and any options besides replacing the ECU?

I have had it at a trusted shop and they have no clue.

The car is a stick shift so no automatic transmission electronics on it.

 

You need to "Unplug" what ever is causing the drain. Not turn things On. Open the drivers door, and somhow tape the door switch shut. so that the car thinks the door is closed. Get hooked up and ready to test. If 75ma is what you have all loads off. You can either unplug things in the car, or pull fuses to isolate the circuit untill the number comes down. Then trace that to what ever is causing the problem. A multitude of things can cause a Draw, Test First. Another diag method is to Trace what circuits are "12v" hot. when the key is out of the ignition, and test at the fuse for the draw aswell.

 

 

Mine turned out to be the battery itself. If you're sure your battery is strong, you can try pulling a different fuse each day that supplies power to components not controlled by the ignition to help narrow down the source.

My manual car had a dead battery every day for a week. I pulled several battery fuses until eventually it seemed the fuse that runs the dash lights made the difference. But then the battery gave out anyway and I got a new one. Since then (years ago) I have had all fuses reinstalled with no more issues. It can sit for weeks and still start up right away.