1.2 Polo Camshaft Position Sensor Error even after timing corrected?

[mrcheeezy]

Hi, my son's 2008 Polo with 1.2 BBM engine keeps showing the following fault codes:

16726 - Camshaft position sensor (G40): Signal too low
P0342 - 009 - Open or short to ground - Intermittent

01314 Engine Control Module
013 - check DTC Memory - Intermitent

18265 - Load Signal: Error Message from ECU
P1857 - 000 - -- Intermittent

The fault clears ok, but then comes back and occasionally displays an engine management light. The car runs fine, sometimes it seems to limit the revs to 5000 but then after a switch off/on its fine.

After reading several threads, I replaced the camshaft sensor, I then checked the timing - it was very slightly out so adjusted it so its spot on and then rechecked after a few miles. None of this has corrected the fault reading.

Any ideas where to look next, the engine seems fine but I'd like to get to the bottom of this fault code issue?
Thanks in advance.

[Crasher]

It could be suffering from chain system wear so the timing is unstable. Did you use the cam and crank locking pins?

[mrcheeezy]

Thanks Crasher, yes affirm I used the locking pins and adjusted as per manual. When I checked after a week of driving it was still spot on.

[Crasher]

You would have had the sump off to reset the timing so you can discount a blocked oil pick-up being the cause so I would say fit a timing chain set, they are not very expensive and I would have done it anyway with it stripped down. We sell the Febi kit for £111.74 and it comes with two gears, chain, tensioner and two sliders.

[mrcheeezy]

Thanks, yes I did think at the time it would have been worth doing the chain when the cover was off..... Just looking at Febi kits is it kit 30495 with 118 links?

[mrcheeezy]

Ok, replaced the timing chain, sprockets, guides and tensioner using the Febi kit 30495. No problems fitting, the old chain did look worn and the car runs great and the engine management light went out after about a minute of running.

I then cleared all the old fault codes and took it for a drive all fine and pulls well. However, when I checked the fault codes at home it is still showing the camshaft sensor fault and the ECU error. Here is a pic of the exact codes. Anyone any ideas, on what to try next?:

31621

[Crasher]

Did you use locking tools?

[mrcheeezy]

Yep, followed all the procedures as per EW. Checked the timing after and it remained spot on.

[Crasher]

Change the sensor now and hope that cures it...

[mrcheeezy]

Ok it’s been a while but the problem hasn’t gone away. Is it worth changing the ecu?

[Crasher]

I have a saying, “it is never the ECU, except when it is...”