Intermittent electrical fault - battery drain

[Half_Baked]

Hi all,

Great forum you have here. I've been lurking for a while and reading threads but the time has come to go interactive.

On Thursday my wife's 2005 1.3 Yaris drove her to work as usual. It's a 15mile route taking about 30minutes so the car gets fully warm along the way. On the journey there were no signs of any problem, but when she arrived she did notice that the remote central locking was very sluggish, taking a while to pull the door locks down.

Flash forward to lunch time, she returned to the car to sit in it and phone her mum. Same problem with the locks, and she made a point of checking that all the systems were off (no lights / stereo etc) and sent me a text about it.

Flash forward 4 more hours and she goes to start the car, but it's stone dead. The dash lights will come on, but if you try and turn the key they go off. The starter doesn't so much as click.

To me that sounded like an immobiliser fault, though the car doesn't have one. Via the phone I talked her through pulling the fuses to clear the ECU (no effect) and then to rapidly cycle the key in the ignition to try and unjam any sticking relays (an old favourite of MR2 owners such as myself!). Neither of these worked, so the AA were called.

When they arrived they diagnosed a flat battery immediately, but the guy was quite good. He said it's highly unusual for a battery to be fine in the morning, dead by the time you get to work, so he checked it over. The battery itself, apart from a shortage of electricity, passed the test.

Next he moved on to look at the car. Initially he was finding nothing. 0.12A being drawn for a few seconds after the car was locked then basically nothing. He found an engine code (P0340) which is the cam angle sensor, but on investigation that probably means "engine not turning when engine start requested" rather than a failure of the sensor itself.

He was about to give up, when he noticed that the ammeter reading had shot up to 3.5A with everything apparently off and locked. He tested it a couple more times to be sure but the reading was confirmed. At that point he seemed to run out of ideas - stuck a booster pack on it, let it charge for a bit then sent my wife on her way.

Later that night I went out to look at it, and to my intense annoyance, it's absolutely fine again. The only thing I could find that pulled 3.5A was the indicators, and I'm sure that the AA and my wife between them could have spotted it if that was to blame!

We're now left with a car that I don't trust to ferry my wife around an no obvious way to fix it. We've been using it since and there's no warning lights, it's holding charge and there's no sign of the drain. It has absolutely no modifications - so whatever's happening is something Toyota put there.

Any ideas??

Thanks!

Alan

[Half_Baked]

Turns out that the passenger door lock was sticking. Still drawing full "door locking" power for a whole day.