ECU relearn period or TSB?
 

So about a year ago, I got fed up with the idle bouncing super low and got the following TSB work done : S-SB-0021-15 where they update the logic for the TCM.

This morning, my car battery died so I had to get a new one, which as I understand it resets the ECU? I know that after disconnecting the battery, there is a sort of relearn period where the car attempts to relearn how you drive for the first 100 miles or so. Now as I'm driving around, the 500-1000 RPM idle bounce is back, and the throttle response is squishy as all hell (doesn't even start to rev until 10-15% depressed). I've probably put ~20 miles on it with and without AC on and a mixture of highway and city streets since the battery removal.

My question is this--is this standard relearn period behavior, or has the reset undone the TSB work that I got taken care of? I apologize if this is a silly question, searching found me nothing and I'm not particularly adept at the electrical side of our cars.

Thank you!

Not a silly question. The TSB was literally the installation of an updated program on the computer.

The computer collects all kinds of data that tells it what the engine is doing. Then the program controls the engine a certain way.

When your battery died, all that data was lost so the program has to work in a default/dumb way until it collects enough data from the engine to go back to working normally.

Ask away if you want to dig some more. :)

I appreciate the answer!

You say 'all that data was lost', I'm assuming you mean all the data it collected about how I drive, but not the data that is the new program the TSB installed, correct? So hypothetically, should I expect the squishy throttle and idle bounce to correct itself or should it require the TSB work again?

Yes, that is what I meant. Not hypothetical, it will be fine. Buried in this forum are some tricks you can do to accelerate the learning process. Basically, it does its best learning when under steady throttle for extended periods of time; highway driving. It will take longer if you do all stop & go but no sweat. Either way, it will get there.

Excellent. I really appreciate your time, gonna go do some highway cruising!

No worries, man! Love to share. I don't know the finer details of this system but they all learn when the system is running in "closed loop" mode. Think of this as when the engine speed corresponds to throttle setting steadily for a while.

After the engine gets up to normal operating temperature, drive along steadily at a fixed throttle position. I understand it helps to do this at different engine speeds but like I was saying, I'm ignorant of the details. :(

Ahhhhh.........YES! ........ I see a road trip for you and your car this weekend ......maybe to Las Vegas ....... :happyanim:


humfrz

Just got back, did a good number of miles highway cruising and the car is responding much better now! Thank you!

I'm gonna say this, and it may be an obvious one, but has your air filter been replaced and/or cleaned (if it's a reusable one). I forgot to clean mine and the car started to idle bounce. I was confused as to why it would do this, then thought about the filter. It was clogged. Cleaned it up, and the car idled like normal.

Clogged with Starkville, Mississippi mold no doubt ....... ;)


:lol:


humfrz

...says the guy with moss growing on his car. :barf:

It's a good question, I have a K&N reusable drop-in that I cleaned...probably 10k miles ago? Probably due for another cleaning soon though....
Most of the problem seems to be resolved, but it can't hurt to have a look at the filter too!

Not so, I spray it down the outside and mist the inside every day with a mixture of chlorine and moss-out....... :thumbsup:

Unlike my neighbor's car ........ :rolleyes:


humfrz

That'll buff right out.