^Yes

07 TCH - slightly modified

Thanks! Would this make the ICE run more often to recharge the 12v battery?

Not to any significant degree.

07 TCH - slightly modified

schmidtj — Can you see if there is a TSB called something like "ISC Learning Procedure" for the TCH? There is one of this title for the 2007 Highlander Hybrid (TSB2606 dated 2006 August 28 in Canada — but Toyota Canada releases their own versions of the U.S. TSBs, so I don't know the U.S. TSB #). My reason for asking is that this TSB addresses the question of what one has to do in the way of Idle Speed Relearning after disconnecting the 12-volt battery. I'm still trying to track down whether or not the TCH needs this done each time its 12-V battery is disconnected. I don't know whether there's a corresponding TSB for the TCH. Please check! Thanks.

Stan

I disconnected my 12v negative terminal last night while installing my XM tuner. Along with losing my presets in my non-NAV JBL radio, my tank average was also reset to 0.0, even though the main odometer and both trip odometers were not affected. This effect was not mentioned in earlier posts.

CAMRHEE Hybrid - FOR SALE!!!!
Completed Mods: RK-Sport body kit, 18" LexusGS430 wheels 235/50ZR18 tires, TRD/SE springs, Rear Lip Spoiler, Terk XM-Direct, Smoked tail lights, Sliding Armrest, Rear Bumper Applique, Front License Bracket, Lower Grill chrome inserts, K&N, Blaupunkt THB200A sub, moved rear HSD emblem
Future Mods: fog lights, black chrome my wheels

http://www.greenhybrid.com/share/fil...fterFront4.JPG

I also had my 12-V battery disconnected for an hour or more last week, when my Toyota dealer changed the dc-to-dc converter to the newly redesigned unit, as per TSB EG059-06 posted to this Newsgroup a while ago. [My dc-to-dc converter had not failed — this was just preventive maintenance due to its potential to fail.] There was no need to do the Idle Speed Relearning procedure — see my posts near the beginning of this thread. It idles the same as it did before. So, it seems that the instructions given in the Initialization pages of the Repair Manual do not need to be done under normal circumstances, as surmised by the master technician at the dealership.

One side benefit of disconnecting the 12-V battery seems to have been that I can now change the door lock/unlock options, as per the Owner's Manual pages (~ page 42). I'll have more on this on the appropriate thread once a few remaining questions are resolved.

Stan

Stan, sorry for the belated reply but I've been "out of touch" for a while, so never had the chance to help out again... That said, looks like you finally figured it allout regardless. Thanks again for your post/report, really helpful!!!

Just to answer the original question.... You don't need to disconnect the battery to reset the DVD/Nav system. I pulled the "Radio 1" fuse under the hood and the "Radio 2" fuse in the interioir fuse box and waiting about 5 minutes. Put the fuses back and started the car and it forced the radio/Nav system to reload the firmware.

BTW, the only thing I lost was the radio presets.