So what's the deal on losing OBD memory if the battery goes dead or is disconnected? I read this on another forum:

"Please note ... as I just mentioned in another thread, if you disconnect your battery or it goes dead, you lose your
OBD memory. I failed inspection for it, and just had it reset by my Chrysler dealer - cost me $68. Be careful."

 

It's been over 24 hours since I posted this... what, no one knows?

 

you do not lose the actual obd system memory just the info it gathers... he failed inspection cause his emission checks were not run since he did not drive the car enough after he fixed his battery issue. there are a few emission checks that are only run when certain conditions are met such as speed and throttle positions. his dealer ripped him off, he could of just driven around for a week and passed inspection no problem ... no different than what they did using their drb3 tool.

 

I would have been ticked. The dealer should have said something to the guy. But on the other hand, if ya don't know, then ya don't know and ya did what ya had to do. Did I say that right??

 

Thanks for the reply.

I understand your words, but not the reasons for all the parameters and how they are lost and gathered that effect the emission tests.

 

well hmm how can i explain it better ... since most states do a emission check without a sniffer on the tail pipe now just a plug into the OBD2 system, the system has to be able to tell it if everything on the car emissions related works correctly ... so the OBD2 system in your car checks the EGR system by activating it when the car is driven at certain speeds and throttle conditions, and checks the o2 sensors to make sure they are reporting valid voltages and are not damaged ... checking downstream o2 to see if the cats are functioning correctly ... check to see the air pumps operate properly at startup ... all these get saved into a volatile memory form, meaning when power is lost, the memory wipes ... while the actual OBD2 system is saved in nonvolatile memory, meaning when power is lost the data remains in it ... kinda like the RAM vs the BIOS in your PC ... one is meant to be written to and changed and the other is meant to store static data and never be changed.

hope that helps a bit ...

so when you disconnect your battery and reconnect it ... if its plugged into a emission test machine the values for things like o2 check, air pump check, cat check, and EGR check all come back as failed since the system did not get a chance to run those tests yet. it takes usually a week or two of daily driving to run all the tests as they are run over a extended amount of time to show all systems can function during various operating conditions and over prolonged usage.

 

Thanks for taking the time, that explained it very well...

I understand now how he could of drove around until the OBD gathered the new information and stored it.
How is it then, that the dealer was able to reset everything and rip him off the $68 ?