Hi

My 2007 IS250 recently developed a starting issue.
It will run fine for a week or two or a month, then suddenly won't start in the morning. The start button light is green, the dials light up and the needles does it's usual across the dial show, but the engine doesn't turn over.
if I try again 3 hrs later, it starts fine. I have had a Service Centre run diagnostics which came back all clear. They have also said they can only test it again to check what the issue is, if they have the car while the issue is present ( which is obviously impossible to predict)
any suggestions? ( I had the battery checked as a precaution - it's fine)

 

No sound from the starter, fuel pump or else?
Do you have aftermarket Remote Start installed?

 

All the usual sounds are present ( whirring, steering wheel moves out and into set position), engine just doesn't turn over. And then 30 min to 3 hrs or so later, starts normally as if nothing is wrong
Car is still stock standard.

 

Is there any place you could get your batter load tested? As well inspect your battery terminals for corrosion. Maybe a loose connection.

 

Had the battery checked out earlier in the week. No issues. Terminals are also fine.
Next step is to have an Auto Electrician check it out but that's probably only going to happen after 3rd of Jan, with most businesses closing in the next few days for the holidays
Could the issue be the starter perhaps?

 

If you check on YouTube. You can always try the whack the starter solenoid. If it starts after a few whacks then most likely it's solenoid related.

For the ISX50. Not sure if you can put a wood rod from up top. Maybe it will have to be from the wheel well, or under the car. Just use safety measures.

 

Can we absolutely confirm our terminology is the same?
Start button is pushed, engine spins over but does not start.
Start button is pushed, engine makes no sound of turning over. Lights do not dim or flutter. Nothing happens with regards to engine spinning over.

The reason I ask is some relate "turning over or cranking over" to mean it is running. IMO turning over is cranking over by means of the starter but it is not running.

Can you confirm that is does not crank/spin the engine in an attempt to start?

What is wrong has two very different answers depending on if it cranks but won't start or it randomly won't crank over at all.

 

Following.

I've been struggling with a similar issue in my 2009 IS250 that is completely stock. Randomly decides not to start with the exactly same symptoms. Starter relay does not even get voltage. I was able to run a jumper cable from battery directly to the relay connections and it started right up (bypassed computer). Replaced starter relay, neutral safety switch, crank position sensor, fuel pressure sensor, then finally had my local Toyota club mechanic take a look. He only got it to happen 1 time over the span of a couple of days (full diagnostics showed no issues) and thinks it may be the transponder receiver in the dash. Finally, I got a recall to get my dash and door panels replaced so I took it into the dealership (didn't mention the starting issue). When I picked it up, they never mentioned anything and it's been running great for about 6 months. All of the sudden, the issue started again this week. Would love to hear what the auto electrician comes back with on yours!