Dean2

Your battery may be just fine. No modern car stays charged if not driven for a month. This might help. If you do need a new Battery, I second going for a Costco or Walmart replacement. If I am paying forthem,all my batteries are Canadian Costco Kirkland. Far cheaper and a WAY better warranty than any other. Basically 4 year full replacement, 48 to 100 month pro rated. That is over 9 years warranty coverage. U.S. warranty on the Costco batteries is not as good, I think it is 3 years. Kirkland Signature Automotive (flooded battery) 0-to48 months - Free replacement 49-to66 months - 50% refund based on purchase price 67-to100 months - 25% refund based on purchase price The Panasonic Batteries are not superior to the others. However, if your original battery is Lead acid stick to that, do NOT go AG, same is true in reverse. The charge mapping is different between the two types and you want to stick with what your car was programed to charge. (Some cars are capable of adapting to either kind of battery but I would make sure before switching.)

Break in MIGHT change your gas mileage by 1 or 2 mpg, it won't change it 5 or more. All city driving and an aggressive driving style you are NOT going to get the posted mileage. The skinny pedal rules. Lots of stop and go with quick leaving of the stop light gets poor mileage. Just by adjusting my driving style I can go from 15 MPG city to 22 on the exact same routes. I live with the 15 mpg because I don't enjoy driving like Grandpa. Same applies to highway driving, can go from 24 to 33 depending on how much Ricky Road Race I play. 7.2L/100 is 32.7mpg. Driving very conservatively in the mountains due to heavy traffic and no room to pass. 4.3 litre V8 in GS430. Same stretch of road I have got as low as 12l/100 or 19 mpg. Hand calculated is usually within 3 or 4% of the readout.

Glad the info helped. You can use the quick connect cable on the jump start terminals as well, they don't have to go on the battery itself. The reason I put them on mine was so I don't have to remove any of the under hood covers or the battery cover to hook up alligator clips each time I wanted to put the trickle charger on. On my LS you can't reach the battery terminals without opening the battery cover by the windshield. Here is a picture of the LS460 Battery location. The panel with the Yellow sticker has to be removed at min to get alligator clips onto the battery.

Did you ever get your parasitic drain issue figured out and if so what was it? Thanks.

The above should help. Batteries are lead acid, at least up to 2022. As far as where to connect it, trunk to battery or under the hood to those terminals makes no difference. It is a matter of what works best for you. Use the quick connect cable and it makes it really easy to connect the charger when needed. You can also get Noco trickle chargers that mount permanently in the car. https://no.co/products/charging

If you are having issues with your idles speed, smoothness of idle etc, especially after disconnecting the battery or servicing the throttle body, you may wish to follow this idle relearn process. Start the car, take it for a short drive and make sure the temperature gauge is at full normal operating temp. Engage the parking brake, turn off ALL systems, radio, AC/climate control etc and shut the car off. Turn the key to on without your foot on the brake [don't start] then off. Turn to On again without starting, then off. Start the engine. Make sure the park/e-brake is still engaged and keep your foot on the brake. Put the car in drive, CAREFULLY take your foot off the brake and ensure the parking brake holds, and wait while the car adjusts to it's normal revs, should be 600-800 rpm in drive with AC/climate control off. This takes about 5 minutes. Switching the key on and off twice and starting engages the relearn mode. If you are the visual learn type, there are YouTube videos of this process available.

As a followup, Charged the battery to full, after an hour off the charger, read 12.73. July 2023 OEM Lexus battery. After sitting in the garage un-driven for 8 days, battery now reads 12.45. So the constant drain, even though very small, definitely draws down the battery over time. Battery went from 100% to 80% in 8 days. Still lots of juice to start the car. Left parked with no trickle charger, and assuming an even rate of drain the battery will be down to 50% in another 12 or so days. At 12 Volts it is still enough to start the car but this is NOT what lead acid batteries like and will materially decrease its service life. If you aren't driving the car regularly your battery will last far longer if you put it on a .75 AMP to 2 AMP smart trickle charger like a Noco. The other option is to disconnect the negative battery during storage, but I find it a lot easier just to leave it on the trickle charger.

I read a great deal on various forums about people having issues with parasitic drain on their Lexus vehicles What I did not read was very much useful info on how to diagnose the issue. Thus I thought, I would run the test on my 2015 LS460 SWB AWD. I started with a quality Multimeter that has both DC and AC current(AMP) measuring capacity. You put the black lead into the common port, and the Red lead into the 10A port, may also be labelled just AC/DC A on some meter. Having Alligator clips on the end of the probes will make doing this a whole bunch easier. I shut off the car, put the key FOB in the house in an RFID box, left the doors unlocked, and lifted the hood. My car does not have a hood open warning light so no hood open sensor that needs to be defeated. I disconnected the negative terminal on the battery, clipped the Red Lead to the battery terminal and the black lead to the Negative cable. I then opened and closed the drivers door. Reading popped to 4.8 amps with the interior lights coming on. Closed the drivers door, reading dropped to 2.7 amps and after about 30 seconds started to steadily drop. Within 90 seconds it was down to .7 amp and still dropping. Within three minutes it was reading between .03 and .04 amps, so 30 to 40 Miliamps. I had read that the FOB being too close would cause the vehicle to wake up so I went in the house and got the FOB. Even right beside the car, not change in .03-.04 AMPs being drawn. Used the FOB to open the trunk, reading popped up to 6 Amps. Closed the Truck with the auto close system using the button on the trunk lid, reading stayed at 5-6 AMPs. As soon as the trunk latched the AMPs dropped to 2.5 and then kept dropping following the same pattern above. I tried a number of different combinations and permutations, including putting the push button start in the run position without stepping on the brake so the car didn't start. Remember, your multimeter is limited to 10 AMPs, if you start the car, or turn on high draw things like Headlights, you will likely pop the fuse that protects the multimeter. No matter what combinations I tried, the at rest reading dropped back to the 30 to 40 miliamp reading. The only thing I didn't do that I wish I had done, was lock the doors and see if the at rest reading increased with the security system active. Since I park in a secure garage and never lock the car, I didn't think about that till I had it all buttoned up again. Since the car sits for long periods of time I have attached a NOCO harness to to the battery terminals to make hooking up the trickle charger much easier. This way I can just plug the trickle charger in without having to remove the clips and lift the battery cover each time to attach alligator clips. I have these quick connects on all my vehicles. Even at only 40 Miliamp, a battery will drop below starting voltage in about a month, if it is stored cold it will go flat faster than that. Remember, lead acid batteries do not like to be discharge down to 11 Volts and recharged. They are much happier and last far longer if kept above 12.3 volts and that means a trickle charger is a good idea if you don't drive your car for at least 30 minutes every 3 or 4 days. Hope this information helps those of you suffering from batteries going flat. Multimeters have a lot of different layouts, this is just for illustration. Untitled.avif

The 2008 GS 350 is a 6 cylinder and has a timing chain and does not require replacement. The 2006 GS 430 and all other 8 Cyl 4.3slike the SC, LS etc have an actual Belt. I just replaced mine at 150,000 Klms. It was still in perfect shape. The water pump was pristine but I replaced it too while I was in there.

2006 GS 430. OWNERS manual instructions do not work. What does work is hold up button until roof completely opens and then completely closes. One touch will be re-enabled.