Possible cam chain stretch?

[kam760]

Just wondering if anyone could provide some advice please.
Cam belt / chain / tensioner done within last 18 months by the old owner (with receipt). No rattle at all.
I've done around 5k miles since - car always felt like it had a very very mild misfire - just a slightly hesitant idle. Not enough to make me think bad coil pack (though packs/plugs were changed anyway out of OCD)

MIL on today with P000A and P0016.
-Camshaft Positioner (Bank 1 Intake) - Slow Response - Intermittent - MIL ON
-Bank 1: CMP Sensor (G40) / Engine Speed Sensor (G28) -  Incorrect Correlation - Intermittent     

Timing values here:


Think the chain can stretch this quickly (at 6° already!) or is it likely wasn't done correctly when replaced? Wondering whether it is worth changing the G40 sensor anyway, but that wouldn't explain the phase value would it?

[ald1717]

no way the chain would stretch in that time, i would lean towards sensor especially if theres no rattle

[kam760]

Thanks, i'll order a G40 and N205 (ouch at the price) from TPS tomorrow. Luckily it's not my daily. If that doesn't solve it I assume it's the chain or VVT adjuster.

[ald1717]

have you asked a vag indi for their thoughts im no specialist i was just saying a genuin vag chain and tensioner wouldnt get slack in that short of time, and if it was the adjuster it would also most likely be rattling, if you rule those out its definately more likely to be a sensor,   hope you get it sorted

[kam760]

Yeh booked in but next availability is 2 weeks...thought I might as well change sensors whilst waiting.

[pudding]

I would do some logging before buying parts.

"G40/G28 incorrect correlation" could be either sensor.  The ECU is basically saying it doesn't know where the cam and crank are in relation to each other.  G28 is about £140, G40 is £40, so I wouldn't fire the parts cannon just yet.

Slow response VVT is usually either: a busted oil control ring in the chain cover, wear grooves in the VVT adjuster bleeding off oil pressure or a Faulty N205 (rare).

-6 probably suggests the VVT side is faulty.  It does normally tweak itself to get to around 0 to -3KW.  Bad timing would show a lot more than -6, and the actual and requested angles wouldn't align.

[Jus10]

Any update on this? Having the same issues.

Replaced cam chain, tensioners, rings, etc.  Drove great for about 4-5k miles and now low boost, tough idle when warm, P000a P0016 codes.