Intermittent VANOS Code 72 - Inlet late valve

[Slideways]

If it ends up coming back, the intake piston seal could have been slightly damaged when it was installed. Another forum member pulled the pistons out to find that they had a damaged seal (install error), but I don't know what codes they had.

[Pklauser]

Well boo, code 72 came back, this time joined by its friend 184 - camshaft actuation. Again intermittent though, I've only seen it once in roughly 1k miles.

This is leading me to think it's either the VANOS seals - which are ~4 years old, or this new solenoid pack from a year ago is junk.

[Pklauser]

Replaced the intake cam sensor as it was original, just in the off chance that would change behavior here. 72 came back.

Interestingly enough INPA gives a little more metadata with the error:

Line break or value missing
Error Emission Relevant OBD
Error currently not present sporadic error

"Line break or value missing" is interesting to me. Can't tell if that's just generic text that gets tossed in there with the code, or if this is trying to lead me to a more direct cause, which would make me think solenoid pack over piston seals. I'd also expect bad piston seals to show poor VANOS test results.

I got my solenoid pack from FCP, so I can easily order another and do a replacement, but it feels shitty to do that if the solenoid pack isn't actually the problem.

I think my next step is going to be to pull apart the VANOS unit itself and inspect/replace the seals. This was done by the PO, but not by me, so maybe there is a suspect seal in there somewhere.

[heinzboehmer]

"Line break or value missing" sounds like a SW thing to me, not mechanical. Not entirely sure what INPA is trying to communicate here though, maybe someone else can chime in.

[sapote]

Replaced the intake cam sensor as it was original, just in the off chance that would change behavior here. 72 came back.

Interestingly enough INPA gives a little more metadata with the error:



"Line break or value missing" is interesting to me. Can't tell if that's just generic text that gets tossed in there with the code, or if this is trying to lead me to a more direct cause, which would make me think solenoid pack over piston seals. I'd also expect bad piston seals to show poor VANOS test results.

I got my solenoid pack from FCP, so I can easily order another and do a replacement, but it feels shitty to do that if the solenoid pack isn't actually the problem.

I think my next step is going to be to pull apart the VANOS unit itself and inspect/replace the seals. This was done by the PO, but not by me, so maybe there is a suspect seal in there somewhere.

Man that's a lot of work to replace IN cam sensor for nothing.
Are the text in the same screen with code 72?
Before blaming the vanos solenoid you should try to read the cam angle to see how far off it is; if a little off then the solenoid is working, and if it's off a lot then the vanos piston did not move.

[Pklauser]

Man that's a lot of work to replace IN cam sensor for nothing.
Are the text in the same screen with code 72?
Before blaming the vanos solenoid you should try to read the cam angle to see how far off it is; if a little off then the solenoid is working, and if it's off a lot then the vanos piston did not move.

Yep, text is in the same screen with the 72. Attached the INPA screenshot.

Tough thing with reading the cam angle is that the issue is intermittent. My thought is that since the VANOS test is successful, the solenoid and piston are at least working as expected some of the time. I suppose I could drive around and watch the cam angles, but without knowing what they should be, it will be hard to tell if it's "off". Even then, I'd have to catch it, which seems like a crapshoot.

I have a pressure gauge and banjo I bought years ago to measure VANOS pressure, I'm going to check that out and see what it looks like while running the test, if anything just to have a data point before I pull all of the VANOS off again.

[sapote]

All error occured with hot engine (93C one time which is hotter than normal), and above 2500 rpm so the vanos was activating. No error happened with cold engine, interesting point. Yes, check vanos oil P at hot engine.