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Discussion Starter · #1 ·
I've searched the threads looking to see if anyone else here has had this happen to them and didnt see anything, so here we are.

Yesterday after work my wife went to start our 2010 Rav4 with 110 K miles on it and at first it didnt start. She tried again, then on the third try the car finally started. She drove home incident free. Last month while getting a TSB done at the dealer they did their multipoint inspection and said the battery was weak and needed replacing. I figured that because its been cold and we hadnt used the car over the weekend it could test weak, so did nothing.

So after yesterdays incident we decided to get a new Interstate 5 yr battery for the Rav. I installed the new battery, and went to start it. Nothing. Hmmm? Went to start again (we have the push button start) and the car started and ran for about 2 seconds, then shut down. Hmmmm? Pushed the start button again and she ran fine as if nothing happened. Did not throw a CEL, but checked for any codes anyway. No codes on the ODBII reader. (The battery I removed was not the OEM battery)

So what gives? Is this normal when you install a new battery? We're the second owners and recently bought the car this past Fall. Car has performed flawlessly in the past.
 

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If your RAV starts normally now, the situation which you experienced right after installing the new battery probably was due to the ECU and system adjusting to having electrical current applied again after having none while the battery swap was taking place.
 
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Discussion Starter · #3 ·
Thanks Blogson, thats what I was thinking. These new fangled computerized thangs are smarter than us old dogs! Appreciate the reply :)
 

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2008 RAV4 Limited V6
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When you disconnect the battery, the ECM loses it's memory and all the parameters it had stored for your engine are lost. It goes back to the factory parameters until it re-learns your engine all over again. Same with the transmission. So expect it to idle rough and shift funny for a little while.
 

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When you disconnect the battery, the ECM loses it's memory and all the parameters it had stored for your engine are lost. It goes back to the factory parameters until it re-learns your engine all over again. Same with the transmission. So expect it to idle rough and shift funny for a little while.
Never had any such problem with mine when I changed out the battery couple of years ago. Started right up and never skipped a beat, but I wonder if one of those "keep-alive" units you plug into the cig lighter while the battery is disconnected would solve this problem. I know they are used to keep the radio pre-sets alive but would they also work on the ECU?
 

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Never had any such problem with mine when I changed out the battery couple of years ago. Started right up and never skipped a beat, but I wonder if one of those "keep-alive" units you plug into the cig lighter while the battery is disconnected would solve this problem. I know they are used to keep the radio pre-sets alive but would they also work on the ECU?
I'm glad you brought that up. I'll add a question. Does the cig lighter socket have to be non-switched? Does it work with the push-button ignition? I made the mod that JuneBug documented to keep the socket inside the middle console live. Should I use that one?
.
 

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2008 RAV4 Limited V6
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Never had any such problem with mine when I changed out the battery couple of years ago. Started right up and never skipped a beat, but I wonder if one of those "keep-alive" units you plug into the cig lighter while the battery is disconnected would solve this problem. I know they are used to keep the radio pre-sets alive but would they also work on the ECU?
OK, let's say Jimm57's throttle body accumulated deposits over the years, restricting air flow. Jimm never noticed because the ECM compensated for that bit by bit day after day. When he disconnected the battery, the ECM went back to the factory parameters, which assume a brand new perfectly clean throttle body. It's going to run rough for a while until the ECM compensates again. In your case perhaps your throttle body (only one of many possible factors) was clean and that's why you didn't have any problems.

Yes, the keep-alive unit should work, after all it's just a 12 volt battery. But the power outlets on the RAV4 are switched off with the key off, so that would not work unless they had been modified to stay on.
 

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2008 RAV4 Limited V6
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I'm glad you brought that up. I'll add a question. Does the cig lighter socket have to be non-switched? Does it work with the push-button ignition? I made the mod that JuneBug documented to keep the socket inside the middle console live. Should I use that one?
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That's actually 3 questions. :) The answers are:

Yes.
I don't see why not.
Yes.
 
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