[SOLVED] Parasitic current on a 2004 Sienna Solved

Okay, let me stick my oar in here. 220ma seems kind of high for "keep-alive" current. That's almost 1/4 amp and it will discharge a battery is a few days, or at least drain it enough to make starting the car questionable.

Follow Ray's advice, pull the fuses, one at a time, and see what is drawing the current. Could be a cell phone charger, etc.

Jack

That is a work book from a technician training class from the early 1980's. I'm pretty sure that the acceptable range of parasitic draws has increased since that document was published.

-- snip

My Supra has always been a weekend car and often will be left for a week or more with the alarm on.

After 10+ years the only problems I see are the alternator brushes wear quicker and the weak battery always being charged on the road has caused some corrosion damage from the acidic vapors.

Dan

It looks like the "problem" is solved. I posted this on another forum. It was suggested I shunt the battery cable connection with the ammeter, then lift the cable off the battery post and see what the parasitic current was. When I did this, the current was only 12 to 15ma. I then opened the circuit for a few seconds and reconnected. The current was now back to the high (220ma) reading. I continued to monitor this, and after a few minutes, it dropped to the lower levels (12-15ma). Apparently, it takes a while for the computers to initialize after a power on, before they go into "battery saver mode". I did not know this. This explains everything that I observed on the two Siennas I tested. I just did not wait long enough for the onboard computers to complete their startup. Thanks again to all who responded. It sure was an interesting problem.

Then, why's the battery going dead, or did you replace it?

JoeSpareBedroom, Yes I did replace the battery even though the dealer ran a load test on it and it tested fine. I did not fully believe this test, and I stated I had a new battery on 2/26. While checking for anything else that may be draining my battery, I found what seemed to be excessive parasitic current. I was unaware of the computer startup time after connection to a power source. Even the dealer was not aware of this. Charles Ranheim

Thanks for posting that. It's a handy bit of information to know.

Mark, When I took the current readings, it started out high, then began to step down. When it stepped down from 350 to 220 and seemed to stabilize, I though that was the final current. I should have waited longer. A few minutes later, it would have dropped instantly from 220 to 12 to 15ma. The suggestion the other responder made about taking the reading without interrupting the current flow proved it would eventually drop down. I called the tech person at the dealer I had been working with. He was surprised to hear that. I guess this is not something that is checked very often. I'm sure the parasitic current characteristics will vary from model to model. When the dealer showed me the printout from my old battery load test, it came out higher than spec! However, I still replaced the battery, but continued to look at other things in case it was not the battery. Getting stuck somewhere with a car that won't start can be a bummer at times, especially for my wife. The suspect battery was three years old. I convinced the dealer to replace it under the 3 year replacement warranty. Normally, I replace a battery anytime after 5 years even if it is still working. I can't remember when I had a battery fail within 5 years. I always buy the best battery I can fit in my car. This was my first Toyota battery.

So, after the ignition switch has been off for three minutes with:

Hood latch latched (hood can be open)

Key out of the ignition

All doors closed

All lights off "

Take care, Charles Ranheim

Thanks Charles. This is good information and I saved it to my memory bank.

Good luck with the Sienna, it's a great van. I have an issue with it every 3000 miles, called a oil change :)

d.

I'm glad I found this post. I have a 2004 Sienna XLE that has the same issue with the battery. It only takes a few days of being parked to kill the battery. I've had it in dealership about 5 times. Each time they tell me nothing found, no draws on the battery with everything off (your post makes me question their diagnostics). They've replaced the battery and recommended I put the car on a trickle charge or solar charger continuously. What the HELL? The consideration is I put low mileage on the car each day. It doesn't seem to be an issue with all my neighbors who have similar driving habits, but drive other vehicles, two of them toyotas. Their cars start right up. I too keep the automatic lights in a manual mode and have turned of the interior light switch to prevent any unexpected or additional draws on the system to try and ensure a start the next morning.

I appreciate the post regarding pulling fuses until finding the culprit circuit. The hard part will be conveying this to a service writer who is not at all enthused to hear / see my name on a service order. Thanks again!

Do you have any aftermarket accessories installed like a remote starter or security system?