"Do not disconnect the battery cables before contacting your Toyota Dealer"

So my user manual says this, twice:

Does anyone have any idea why? My local dealership has no clue.

 

Probably saying that so that people don't try clearing their codes (check engine light) before the dealer has a chance to see them...although the codes get stored in the ECU anyway even if you clear them by disconnecting the battery, so I don't see the big deal.

Maybe it restarts the emissions cycle or something and they don't want people doing that before they can diagnose what's wrong

 

Both pages seem to have to do with airbags, though.

 

You might let all the electricity leak out!

 

Removing the battery cables allows some of the short term memory codes to be erased (soft codes )
In a case with the air bags , I am assuming there is also a possibility of accidently clearing short term safety codes from the body module .
This would make it tricky to diagnose if the dealer was unable to reproduce the issue

 

*calls dealer*

Hey I'm gonna remove my battery cables. K bye.

*dealer service guy confused*

 

Yup. I just ran across this in the FSM, while looking for something else entirely:

 

*turns to co-worker*

"Dude, that's the tenth dam call I've gotten with someone telling me they are disconnecting their battery. WTF is wrong with people?"

 

So what if your battery craps out and you need to swap it? Do you need to call the dealer first?

 

For years, I've disconnected my battery at least 4 times a year to clean the MAF sensor or as I did yesterday, to clean the crud off the terminals. I keep my Tacoma on a trickle charger cause I barely drive it anymore and crud forms on the terminals. The only consequence was having to reset the radio buttons. Fucker still runs better than when I bought it new.

 

Yeah, that's what I was trying to find out. When I called the dealer, they had no idea. Apparently it's really just if you're having problems with your airbag system.

 

Ta-da!

 

my understanding of the "system" is that if you have the PS air bag turned off and the DS bag has been deployed that there is no reset that you can do so the PS bag is now non-op. I think Toyota realizes that people will drive the auto with the DS bag removed and no SRS at all. I think this is lawyer stuff...

back in the day... I went round and round with and insurance adjuster, the service manager, the Audi regional rep about an Audi that had been in a front end a mild front end collision. New model introduction training said that the seat belts need to be replaced as well as the pre tensioners and the air bags weather or not they have been deployed. The seat belts had tear away stitching, a small loop of belt webing that pulled the stitches out during impact to reduce the G load on the occupant. When I was over-ridden on what the manual said I noted on the R/O exatcly what was happening to CYA.