Hi guys.

I changed my timing chain about 2 years ago. It's been fine up until now.

What I've noticed recently is a timing chain rattle for a few seconds after start, then it's fine.

However, I'm now getting dash warning lights. The diagnostic computer gives an error code of P0340 which is a cam sensor error code. I've purchased a new one so I can start to identify which of the 4 is the problem. Fault finding is a bit of a pain as Lexus seal the sensors so well. This search didn't show any of them as being faulty. Want to avoid the ECU for the mo.

So I decided to investigate the timing chain, just incase this was causing the error code issue.

There is a little inspection hatch that gives access to the timing chain tensioner. Adjacent to the alternator.

I've attached a photo of a very similar tensioner (I couldn't find a photo of Lexus one)

This part (Circled) which I think should control the ratchet to stop the piston on the tensioner from returning to far. However on my engine it just swings loose.

Is this normal or should it be locked in some way?

Sorry for the long story.