mr29rose

do i lose my phone contacts and speed dials?

jlawr

No you don't. Everything is saved to the HDD.

You will need to reset your NAV map location (ie, TX/OK or CA, etc), and you may need to reset your Radio Stations.

No worries.

melnick

The only thing that I lost was previous location in the Nav system. All other NAV settings and memory was saved.

jmcraney

Nothing is said in the TPMS section of the owners manual about reinitializing the TPMS when the battery is discharged or removed, and I was under the impression that the TPMS did not have to be reinitialized for that. However, in the Steps To Take In An Emergency section of the owners manual it says "When the battery is removed or discharged: The tire pressure warning system must be initialized."

For those of you who are not well informed about the TPMS: Initialization of the TPMS involves more than just reaching under the dash and pressing the button.

305Busa

I disconnected my battery for about 45 minutes while hooking up my lowering module and the only thing that I had to reset was the temp on the AC. It went up to 75*. Besides that, everything else stayed.

DrQuality

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.