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2004 ES330 power drain

I have a power drain issue 500+ milliamps and it goes down to like 20-50 milliamps when I remove the fuse for ECU-B which according to the manual is involved with these systems:

The tail lights are the only affected system far as I can tell.
They do not work (new fuses and bulbs were installed).

I was hoping this power drain would be for a fuse I could live without but there are a lot of things affected by it.

Anyone got a hint for how to proceed?
Thanks much.

The car may think somebody is breaking in or that the owner is getting in to drive it. Could be caused by a faulty door switch. I’d start there.

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You need to check each of the circuits that are tied to that fuse until you find the trouble maker. When you disconnect the bad circuit the current will drop down to a normal flow. Start the hunt by trying to pick the most likely circuit to give a problem. Since the tail lights aren’t working you might start with that circuit. The trouble may be a within a module.

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Did you wait 30 minutes with no activity to ensure ECM sleeps?

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The part that stands out to me is wireless remote control system, which probably refers to the key fob. Make sure there aren’t any keys anywhere near the car when you’re testing the power drain, because key proximity can wake it up and make it start draining power.

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The values you are seeing are typical, 500 milliamps for a few minutes then 30 to 50 milliamps.

Be sure to remove the key from the ignition and close the hood latch so the computers can go to sleep, there is a switch on the hood latch for the body computer and security module.

I’m very grateful for the responses.:slightly_smiling_face:
I will keep all these ideas in mind as I troubleshoot.