Low Idle After Battery Disconnect for 11 Days
 

I had disconnected the battery for about a week and a half because my wife drove my truck while I was on a long business trip, and one of the buttons on the key fob got stuck, and triggered the panic button in the back of the fob. Before she realized that was the cause, I told her to just disconnect the battery to stop the alarm from going off (I was at a job site and couldn't spend too much time troubleshooting).

When I came home last night, I took the truck out for a drive and run some errands, when I noticed the idle was pretty low, at about 500 rpm, sometimes lower, when in gear. However, after driving around for about 4 miles, the idle slowly went back to normal. I was wondering if this is the expected result after losing electrical power for a prolonged period of time, or should I be concerned? I know the idle rpm is controlled by the ECU, but I wanted to make sure.

Thanks for your help!

is it back to normal since then or low again on the next restart?

when my alt went out it was doing a similar thing on a test drive and turned out it was barely charging over the amount discharging and i was able to see that by testing the voltage at idle. not certain but maybe low battery couldve caused it and once recharged via alt it came back to normal.

It needs to relearn the adaptive parameters. Position of the IAC during different conditions is one of them.

It should get better.


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It’s back to normal now. I just wanted to make sure that I don’t need to do anything during the re-learn process. I figured if it didn’t die at stop lights, then chances are things are ok.

Thanks for the information!

Even if it did die it would still relearn pretty quick. You may notice a cold start issue with temperature changes. Warmer or colder doesn’t matter. It seems like every 20 degrees is a new adaptive that needs relearned.

The fact that your default adaptive do not work anymore to me means your engine is old and tired, I’m sorry to put it that way......


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I briefly had a 1st gen sequoia that would do that if the battery died, it would stall usually once and then run normally, my 4Runner doesn’t do that but I’ve never had the battery disconnected for more than a day or two and never had it die

My wife's 05 Subaru Outback is can-bus and requires a lengthy procedure of key off/key on, run for a few minutes blah blah blah after a power interruption for idle calibration. If not performed, it will not idle properly. It never re-learns on its own.

I've got a low idle issue myself. I've seen as low as 450 on the UltraGauge at stop lights since returning from 3 days in the dirt and a 1000 mile road trip. Will see what it takes to fix and report back.....

Also - it's intermittent.

Have this issue too (also intermittent) but the vehicle is driven every day. I cleaned the IAC Valve a couple of days ago which did help but it's still doing it a little bit.