My car has been consistently resetting its ECU and clearing memory. I still can get it started and drive it fine, but I have to enter the radio code about every other day. It hasn't been a problem except now I need to get an emissions test and there isn't data for the computer to pull for the Cat at temperature etc. Tags are expired and I got pulled over the other day for them.

It as if the car is losing power periodically to the ECU. About every other day when I go to unlock it, the keyless entry won't work. I have to unlock the door manually and fiddle with the key in the ignition before the car acts like there are no issues and starts right up.

I have a handsfree link issue and will replace the faulty capacitor tonight ... but I don't think that is wiping the ECU. It shouldn't be. There is plenty of power in the car when it needs it, and the problem isn't happening all the time. You just need to fiddle with it, it decides there is power, it starts up and I enter the radio code like nothing happened.

Any ideas on what is causing this short/memory wipe? I can buy a new ECU on ebay, but don't want to do that if that isn't the issue.

 

What kind of shape is your battery in?

 

It sounds like the entire car is losing power, not just the ECU. Check your battery terminals. I'd remove them both, clean them with a wire brush. Clean both the battery posts and the wire clamps. Check to make sure the ground is well attached as well as the positive connection. Again, remove and clean and reattach.

How's the battery? I'd go to Autozone and have them test both the battery and alternator. They should do that for free.

 

I thought the battery was decent. I checked it about a year ago and they said it wasn't an issue. I took it by JiffyLube Saturday for emmisions and they said that there was a cell that was dead. I have never needed to jump it. It just starts on its own, and starts quickly. Maybe the battery has intermittent issues. I can take it in.

 

If it starts fine then it seems like it would be providing enough juice to keep the ECU and the rest of the systems from getting too little voltage and resetting. But any voltage fluctuations or inconsistencies can cause things to go funky. There's been some weird stuff that's happened to both of my TL's (3G and 4G) when the battery is acting up. I'd definitely go that route before forking out any cash for a new ECU. It's very uncommon for an ECU to go bad in these cars.