..what will I need to reset afterwards ..So far, I figure Radio stations, seat memory, maybe TPM .. I seem to recall that if the swap is quick ( within 5-10 minutes) , not much ...

 

If you can get the new battery connected within 20 minutes all the settings should remain the same, mine did. Not one setting lost.

 

i did mine w/the engine running (just in case). just be careful not to touch the pos terminal to ground an you'll be fine...

 

I would discourage changing the battery while the engine is running in the strongest terms. As Shibumi said you cannot let the positive terminal touch anything, but even if you are careful there, without the battery in the loop it is possible for voltage spikes to fry all kinds of electronics in the car. That will be one expensive repair as I'm sure Lexus wouldn't cover it under the warranty.

I haven't had to change mine yet, but I'll plan to do it quickly and hopefully preserve the settings. Even if they are not saved, to reset them once every 4 or 5 years is no big deal.

 

Thanks .. I wouldn't do it w/ the engine running, but can do it quickly as I'll have help ... Looks like I'll go with the Duralast Gold ..had good luck with them over the years .. Was thinking of an AGM Die Hard Platinum, but i understand they're sensitive to 'overcharging', so , I'l stick w/ the older lower tech on this one ..

 

Went well ..and no settings disappeared ..Climate control needed to be turned back on to Auto .. Forgot about all the little damn plastic screw-nut-thingies , and , just remember, take the new battery OUT of the trunk before disconnecting the old battery

 

Ha! Did you have to reconnect the old one?

Good tip!

 

LOL iv'e had that happen to me many times in other cars....

 

Oh yeah .... the dog that was supervising us was grinning knowingly ... I

 

With my prior Toyota vehicle, an Avalon, I discovered it was useful to accumulate a list of the items that need to be reset after a battery disconnect. Then, whenever the battery was disconnected going forward, I would just print out the list and punch-off resetting all the items. The battery has now been disconnected three times on my recently-acquired 2007 LS460, so I have a pretty good working list of the items needing reset. I figured I would share it so that other owners have a starting point for items to check after a disconnect.

NOTE: Your model and options may well vary from my vehicle, so this may not be an entirely complete and/or accurate list for other owners. Also, apparently, the amount of time expired during a disconnect can affect what is (and is not) lost. And my own list may not yet be entirely complete.

LOST SETTINGS INCLUDE

SiriusXM channel presets are lost. The SiriusXM tuner box ID number is NOT lost; SiriusXM will restart without issue, albeit on the 'test' channel until otherwise tuned. For some odd reason, AM/FM presets are NOT lost (even though, according the 2007 Lexus LS460 Owner's Manual (page 242), they will be lost).

The cabin temperature setting is lost. Adjust using the up, down & dual buttons to the left of the LCD digital A/C screen.

The instrument panel brightness setting is lost. Adjust using the up & down arrows just below the temperature gauge in the instrument panel.

The AutoOn setting for the electrical parking brake system is lost. Toggle the Auto button, need be.

The BackgroundImagesOff setting for the Center TFT Multi-Information Display is lost. If you wish to turn them off (again), press and hold the DISP button on the steering wheel for at least 3 seconds.

The Cruising Range calculation (within the TFT Multi-Information Display) is made to be inaccurate. This cannot be manually reset and continues to slowly correct as new data accumulates.

The Average MPG (since last reset) calculation (within the TFT Multi-Information Display) is made inaccurate. This can be manually zeroed-out using the Reset button on the steering wheel.

The After Refueling MPG calculation (within the TFT Multi-Information Display) is made inaccurate. This cannot be manually reset and will correct upon next refueling.

The After Refueling Miles calculation (within the TFT Multi-Information Display) is made inaccurate. This cannot be manually reset and will correct upon next refueling.

The Elapsed (Driving) Time (since last reset) calculation (within the TFT Multi-Information Display) is zeroed-out.

The Average Speed (since engine start or last reset) calculation (within the TFT Multi-Information Display) is made inaccurate. This can be manually zeroed-out using the Reset button on the steering wheel.

The NAV system BeepOff setting is lost. Adjust via the path Info/BeepOff, need be.

The Audio Bass/Midrange/Treble equalizer settings are lost. Adjust via the path Audio/Sound.

The Audio Cabin Balance settings are lost. Adjust via the path Audio/Balance.

The Audio Digital Signal Processing setting is lost. Adjust via the path Audio/DSP, need be.

The Audio Automatic Sound Leveling Off setting is lost. Adjust via the path Audio/DSP/ASL, need be.

The TPMS (Tire Pressure Monitoring System) must be reinitialized/reset per 2007 Lexus LS460 Owner's Manual (page 598); apparently any stored TPMS PSI parameters/benchmarks are lost. The TPMS Reset button is at the very VERY bottom of the driver's side dashboard, out-of-sight, almost directly above the top/tip of the gas pedal. Pushing the TPMS Reset button will reset the PSI parameter/benchmark (for each individual tire) at which the vehicle displays the 'low tire pressure' message and yellow instrument gauge light. It will be reset to 25% less than the current PSI for the tire at the moment the button is pushed. There does not seem to be reliable information available as to what the value of the PSI parameters/benchmarks 'defaults to' immediately after a battery disconnect, though it seems reasonable to assume they default to 25% less than the recommended PSI.

There does not seem to be any reliable information as to whether the Tire Change Calibration value is lost, however there is antidotal evidence that suggests the value can be corrupted, so it is best to recalibrate. When a recalibration is initiated, the vehicle will use the GPS/NAV data for at least several miles of driving to compare 'distance traveled' to 'number of tire rotations' in order to calculate a 'current tire circumference' value that is stored and, in turn, used to calculate other values such as MPG. The function is intended to be used when tires are replaced or significantly worn. The function is briefly described in the 2007 Lexus LS460 Owner's Navigation System Manual (page 95). To initiate a recalibration, follow the path: Menu/Setup/Double-down-arrow at lower left of screen (twice)/Calibration/TireChange.

RETAINED SETTINGS INCLUDE

Center digital clock. The clock should correct itself using the GPS/NAV system.

NAV time settings such as DST On/Off.

NAV contrast & brightness.

The 1/2/3 memorized-position buttons on driver's door panel (ie, driver's seat, steering wheel, seat belt height and side mirrors).

Any customized lock & unlock doors 'when' selections.

Any customized door handle 'unlock-at-touch' selections.

Tripometer mileage.

 

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Probably the easiest way to keep your electronics activated so no re-set of car functions are necessary, would be to use a trickle charger:
1. Hook charger up to battery cables several inches from the posts, pos to pos, neg to neg.
2. Turn on charger.
3. Disconnect battery cables from battery.
4. Remove old battery.
5. Install new battery. If smaller, use spacer on the bottom of battery (free with most batteries).
6. Hook up cables.
7. Unplug charger and charger wires.
8. Done.

If you do this, you don't have to reset anything. Just start your car and go.


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On cars with built-in hard drive when you shut the car off and wait about 6 minutes the information in memory that would otherwise be wiped out get copied to the hard drive, can't confirm if the info is saved any other way on cars without it. Here is the extract from the service manual:

"After the power switch is turned OFF, the HDD navigation system requires approximately 6 minutes to record various types of memory and settings. As a result, after turning the power switch OFF, wait 6 minutes or more before disconnecting the cable from the negative (-) battery terminal."

 

A trickle charger makes sense in some scenarios, others not.

The last time my battery was disconnected on this LS460, it was so that the air bag could be disconnected. You need to fully drain the electrical system, including any possible residual charge, before doing so, else the air bag may accidentally discharge.

Also, the last time I replaced my battery in my prior Toyota product, an Avalon, the battery was cold stone dead for almost a day before I discovered it. Too late for a trickle charger by then.

And I can't recall the last time a shop mechanic (that I know of) applied one before disconnecting the battery in order to perform work. I assume they simply don't want any kind of charge whatsoever flowing through the vehicle when they think a battery disconnect is appropriate.

So there are certainly some scenarios where an owner is going to experience a battery disconnect and will be losing settings. Hopefully my list will assist them in such circumstance.

 

One thing I didn't find on your list was the garage door opener. I had my battery out of my '11 LS for a couple of days while installing new spark plugs and found that the opener had to be reprogrammed. Thanks for the list.

 

Thank you for your kind words. And thank you for adding the garage opener to the list.

As I mentioned at top, "Your model and options may well vary from my vehicle, so this may not be an entirely complete and/or accurate list for other owners."

In my case, I do not have a garage, so I have no need for a garage opener reset ... and had no way to test if it even needed a reset.

Best wishes ...