Help with Engine Code

[Ferraz]

Just a little background first. I bought this car (Echo 2004) about 6-7 months ago. Did a computer check (whatever it's called) at the time and there were no errors. I did another check about 3 months ago or so and the guy said the following popped up:

P1346 VVT Sensor (Camshaft Position Sensor) Circuit Range/Performance Problem

The thing about it, is that the Check Engine light has never come on during this time (6 months), and it still hasn't come on up until now. Does this error code not trip off the light? I have a Scangauge tool, should I use it to remove the code, and see if it comes back later on? Also, the error code (P1346) does show up on the Scangauge.

I did some more reading and saw that there might be a problem with the timing chain. I remember the guy who I bought the car from told me that the replaced the chain. Maybe it wasn't adjusted properly?

Any ideas as to what I can look out for. I'll probably take the car to the mechanic tomorrow, but I'd just like to have an idea as to what's going on before I do anything major.

[2005RS]

a quick google search makes me think it could well be related to the timing chain replacement. I wouldn't clear the code then wait and see on this one

[Ferraz]

How would it go bad (so to speak) anyway? I thought these chains last a lifetime. And even if it got stretched, why would it happen so quickly (I think he'd only replaced the chain less than a year before I bought the car). In any case my googling also suggested I have a look at that (and the possible consequences if I don't!).

Would I need any specific info to take to the mechanic or can he readjust the chain as it is (or replace it as necessary)?

[2005RS]

if the chain skipped a cog, then that would throw out the timing.

I don't know enough about it to know if this is possible, but I do know that a timing chain that breaks or comes loose can have catastrophic consequences

you're right to look after these things before messing around with the intake.

[Ferraz]

Now for a (hopefully) update. Didn't change/inspect the chain just yet. To backtrack a little, after I did the inspection about 3 months ago when the P1346 first popped up, I didn't use the car (for three months) until about a week or so ago. The battery was disconnected during this time (so the code would have been cleared).

I only got the Scangauge when I used the car again (about a week ago) and the code popped up (not the Engine Light, mind you) which is why I started this thread (yesterday). Anyway before I went to the mechanic this morning I decided to have look at the code again on the Scangauge, and it was clear! I didn't reset the code, and the battery was connected, etc. so I'm not sure what happened.

Anyway I didn't bother going again when I saw that it was clear (assuming everything was okay). However just a couple hours ago when I was returning home there was a bit of start and stop traffic for about 10 minutes or so. At some point during this time the engine was knocking a bit (immediately I realised that this would have been the cause). Btw this has happened before (the knocking, when driving in stop/start traffic). Then when I checked the Scangauge about two hours after (didn't think about checking it at the time) the error code came up. Would the freeze data (dunno what it's called) help if I posted it here?

Should I just get a new timing chain, or get someone to adjust the old one?