[Shell22]

Yet another VANOS, 2A98, 2A82 thread but maybe with a slight difference, clearly hopeful that I don't need to go under the valve cover on this one but that might still be required...

Anyway, I intermittently get these codes from the intake side, maybe every other week maybe twice in one day it varies. It's usually when the car is hot or close to which does point to oil pressure but only when coasting to idle or at idle/low pull away revs. It hasn't done it at WOT or rapid acceleration or on the motorway at steady speeds. It also has no rough running at any point, no sign it is struggling or 'oh no here it goes again' feelings, just the dreaded beep as it shows limp mode. No issues with cold start and when it throws the codes and limp mode I just have no power. This is what I haven't seen anyone else report. If I restart the engine almost every time (maybe once it popped right back up) I will then have no issues for the rest of the day/journey until the next random time.

The car has done 133k and I have no history (yes stupid and bought with the heart not the head) but i've owned it for 18 months (this issue has only started past 3 months) and slowly worked through the usual service candidates anyway (oil filter housing, plastic water flange etc...). I've had the check valves out and cleaned (unfortunately not tested that they seal one way) but they weren't dirty or clogged, not sure if they were swapped position when put back in.

VANOS solenoids were cleaned to no avail but I've just replaced with new ones, it hasn't fixed the issue I've had one more limp mode since but the performance of the car has improved, low end torque etc... so happy that it's been done.

I was going to swap the cam sensors over but haven't got the right bit to do that and E8 bolts should be replaced so I'll have to get some.

Booked in for a walnut blast in two weeks, lockdown put it back months but it again doesn't run rough so I've waited until how and everything back open.

In short, any words of wisdom on this? From what I've read cam sensors aren't known for failing, neither are check valves usually to blame. If a valve was not holding oil i'd expect poor start up from cold as there is no oil pressure? If this issue is at idle wouldn't that mean the solenoids are not pressurising the VANOS to rotate the camshaft so that would mean oil pressure/cam ledge isn't likely anyway? Maybe the actual VANOS gear has an issue, I saw one video where the spring was loose and the sensor was picking up the spring and throws 2A98 due to invalid data.

Either way thats under the cover and in for a penny in for a pound at that point. I've also seen crankshaft sensor and vacuum issues have some relation to this but again seem outliers.

[Shell22]

Did it today at idle while cold, no rough, no warning, just beep nothing changes but no power...