2007 Yaris Battery Drain

[TheKnot]

Recently developed battery drain on 2007 Yaris hatchback. Took it to a mechanic who said radio was the culprit. Had him unhook radio and would pick up next day. Next day mechanic calls and says computer is also causing a parasitic drain and they don't deal with that. Not a Toyota dealer. Called Toyota dealer. $1000.00 plus labor for new computer. Picked up the car and drove it home. Car ran fine shifted fine acted fine except for one thing which was happening before taking to mechanic. Couldn't lock doors. Tried locking from inside with buttons but would unlock as soon as I shut doors. Manually locked but would unlock as soon as door shut. No key fob. Maybe unrelated to drain. Tried checking drain myself with 12 volt light. Got a dim pulsing light. Pulled ecu-b fuse and light went off. Of course car won't start or run without. Haven't checked any further yet until I get a meter. Hope someone can help me with this problem. Thank you.

[BLH]

A meter would give you a better idea of what is happening.

In my 2007 EWD section. It shows that ECU-B fuse feeds battery power to many control modules in the car. One is the main ECM module but it also feeds other things like door lock ECU, Anti-Theft ECU, power for electric windows ECU.

There should always be some current being drawn. The main ECM module has remember its learned engine parameters and other ECU modules constant 12V power needs.

[la_scanner]

My 2007 Yaris has had the battery replaced five times. It seems a bit much to me.