History:
2008 Lexus GX470 283,000 miles - 1 owner
January 2021 New timing belt, water pump, serpentine belt, tensioner, idler kit (the reason I had this done is at one point I drove the car somewhere and when I got back in the car it didn't start. I let it sit awhile, and then tried it again and it started- drove right to a garage where they had NO trouble starting the car, but recommended replacing the timing belt/water pump because it had never been replaced)
Brand new battery
Of note: at one point recently there was a puddle of antifreeze on garage floor with no known cause/reason

Current Problem:
After filling up at gas station, I entered the highway and while driving 65 mph, I gave the car gas and nothing happened. I was just coasting. I lost power steering, but managed to get it to the side of the road. It would not start again. It attempts to start, but never catches. I've attached audio of how it sounds when I try to start it. When I do turn the ignition it continues trying to start (it doesn't turn off after initial turn).

Has anyone had this happen? Any suggestions would be appreciated. I'll have to get it towed to a garage, but I'd like to be educated before dropping it off (feel a bit vulnerable since I have to have it towed!)

 

So first thing. You had that car for 283K miles and had never changed the timing belt or water pump? Wow, you either got very lucky that belt did not snap or those of us changing them at the recommended maintenance interval were doing it way too early.

I listened to your audio file and mine did that before. It was because my key fell apart and the 'electronic' part of the key (the inside part of the body of the key with the buttons) had fallen out onto the floor of the car. The signal from the module was not close enough to the ignition switch so it never activated the coils to spark and start. It just turned over like yours does.
But since you said you were driving when it just dies then that is not the issue. You should check to see if you have spark at the plugs. If no then then check to see if your coils are still good. If that is good then check to see if you are getting fuel to the engine (is fuel pump running? If so, is fuel getting to the rails with enough pressure)? For a sudden failure like that and no sputtering, Maybe something with the coils or ignition system.

 

Thank you for taking the time to help! I appreciate your suggestions. I'll look for YouTubes to see if I can try some of that diagnostic (based on your suggestions) myself. If not, at least when I go to the garage I will have some ideas for them to look at.

 

Yes, if the security light goes out, then the immobilizer recognized the key.

Otherwise - check the usual three - air, spark, fuel:
Make sure the engine air filter isn't clogged and flows well. Make sure you didn't suck up a plastic grocery bag or similar.
Check the fuses with an ohmmeter (looking at them can't always tell if they're blown)
Make sure you have gas, and that it's getting to the engine.

Chip H.

 

Thank you, Chip! I just bought a multimeter so I plan on checking the fuses. I will add engine air filter to the checklist. I appreciate your help and time!

 

The way it cranks but doesn't sputter or try to fire makes me wonder if there's a failed crank or cam sensor that's not allowing the ecu to know where the engine is in its rotation or something. Have you scanned for any stored codes in the ecu?

 

Because the car had to sit for some time (it was towed from highway to my house), the battery died and had to be replaced. Would that erase any codes?

 

I'm 99% sure that disconnecting the battery will clear most codes stored.

 

Brand new battery is already dead. Might want to check that alternator.

 

that’s a good idea. How long was the car waiting to get towed? Typically a fully charged battery can last for several days before being completely dead, if it was a few hours, then your alternator could be bad leading to no charge and no fuel pump etc etc

 

damn, never known the belts, water pump, pulley... could last 280k miles

 

A similar thing happened to me in my 2007 GX470. I was driving across Wyoming in the middle of the night and lost power to nav, then power steering, then lights. Got it to the side of the road and called AAA. They came and gave me a jump and it fired right up. For whatever reason, the SUV stayed on for the remainder of the trip. I drove it straight to Sears and had a DieHard Gold battery installed(yes this was about 10 years ago). About a week with no issues the brand new battery died. I then suspected the alternator which it turned out to be. Had to get another battery and alternator. How/Why the engine stayed on for the duration of my trip across Wyoming I'll never know. The battery should have died and stopped the engine again if the alternator was dead.
With that many miles, I would replace the alternator ASAP because it WILL die at some point. (I'm on my 3rd now with 188K miles). Through Club Lexus I found this is a known issue with the First Gen GXs.

 

Possible that your alternator didn't just die and stay dead all at once, and worked again for the rest of your drive?

 

Ian, that makes sense. I'm old school and thought alternators either worked or they didn't, no half way, Maybe with the rest of the electronics it stayed partially alive for the trip. God was my co pilot, as it was -10F degrees and blowing 30mph..... anyway, it was the culprit. The timing belt/water pump issue raised by the OP was another act of God that it didn't fail earlier!!! I just had the second put in at 185K miles.

 

Thank you!