Issues after disconnecting & reconnecting battery

CorollaLE2007 · Jan 11, 2015

I had to move my battery in order to change out my headlights, just couldnt get my hand in there to remove them. I had to disconnect the battery to get access to the lights. Its worth noting there was a bit of green powdery corrosion on the negative lead, I took a screw driver and gently cleaned it off, replaced the light bulbs and reattached the battery.

After I reattached the battery I started to drive and when I came to a stop my engine started to putter, When I applied the gas this feeling went away but when I came to another stop it did it again, felt like the car was going to stall. I went down the road to the next set of lights and the car stalled.

I'm looking to the forum for advice on what to do. Do I need to clean the leads again? Could the battery be on its way out? Did I do any damage when disconnecting the battery? Does any internal component need to be reset?

MasterTecInSTL · Jan 11, 2015

Just keep driving it.. the computer needs to relearn everything, including how to idle.

Over the next couple days it will smooth out and work properly...

CorollaCharlie · Jan 11, 2015

Our drive by wire ECU's control throttle. Once the battery is disconnected, it will take some time for the ECU to set and learn a new idle speed. Sometimes mine will take ten minutes- sometimes it takes fifteen or a drive. It should go away once you've driven a little bit. Happens to me EVERY SINGLE TIME and it's really annoying!

PS: clean bad battery leads with coke or baking soda, not a screwdriver

CorollaLE2007 · Jan 11, 2015

Thanks for the quick responses!

You guys are awesome

mikered30 · Jan 11, 2015

Clean the throttle body before you disconnect the battery next time.

YoshiMan · Jan 13, 2015

+1 on the throttle body.

Mine did the exact same thing, but would level itself out after driving for a few minutes... That bothered me, so i looked into it, and yes, it was a dirty throttle body, around the butterfly valve. Once i addressed it, it idles fine after disconnecting/reconnecting the battery. Nothing a little throttle cleaning spray and a rag can't fix!

This guy even addresses it in this video. It's on a Camry, but same principal :

https://www.youtube.com/watch?v=-PsP6ZBKZPE

Marcel13 · May 13, 2023

I have same issues, whenever by battery is disconnected for long, when reconnected, the car drives rough, reluctant to accelerate, loss of engine power etc. What can I do

bennor · May 13, 2023

Marcel13 said:
What can I do

Did you not see/read post #2 and #3 above? In most cases the car runs sluggish for a short period of time while the ECU relearns. Go out and drive the car and the ECU should eventually relearn.

gamer765 · May 13, 2023

The answer is in this thread. Scroll up, not that hard.

rmyoder · May 15, 2023

On a related note, the OP mentioned cleaning the terminal with a screwdriver. He/she posted that in 2014 so I presume the issue has been resolved. For current/future reference, I highly recommend getting a wire battery terminal brush and cleaning them properly whenever they are disconnected. Then apply some terminal protectant or dielectric grease and torque them to spec. Loose terminals will cause all sorts of electrical gremlins.

Issues after disconnecting & reconnecting battery

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