Intermittent VANOS Code 72 - Inlet late valve

[Pklauser]

Whelp, 72 and 184 have reappeared at VIR this weekend. Frustrating.

72 - "Intake VANOS, late valve" again comes with: "Line break, no value. Missing." Though this time it also came with: "Error currently exists". So maybe it's more firmly dead?
184 - "Intake VANOS, regulation" comes with: "Actual value too large".

I don't know where to go next. The VANOS oil pressure was clearly incorrect, but apparently not the root cause.
Looking at the camshaft angles in INPA, they move around and read just fine. I have no idea what they should be to know if they look right.

I can check the physical timing again, and actually pull the VANOS unit off this time to verify I get the cam retarded all the way, but I really think I had it right last time. I will also check the wiring from the intake cam sensor to the ECU, since that isn't something I checked. If anyone has any good ideas here, please share.

Definitely seems odd that it's only present on the intake side.

[sapote]

The errors happened at higher rpm. The bottom of the sreenshot shows hex B8, and other error codes that I have not tried to understand why it listed the long list....

Error at higher rpm could be related to electrical signal on the IN cam sensor. Pull out connector at the DME and have a look, and check the resistance from DME pins to the IN sensor connector pins.

[Pklauser]

Pull out connector at the DME and have a look, and check the resistance from DME pins to the IN sensor connector pins.

Will do.

Did some more testing today while I was at the track. 72 & 184 seem to consistently come back when I'm pushing it, then they started popping up on the street on the drive home as well, including at lower RPM. I cleaned out the solenoid connector in case that was somehow causing an issue. I'm starting to wonder if the solenoid has given up so soon. Going to talk to Lama at Beisan and see what they think/see if I can get another solenoid to test with or something.

nextelbuddy I see you had a thread here recently, did you ever get your 72/184 issue sorted out?

[karter16]

The bottom of the sreenshot shows hex B8, and other error codes that I have not tried to understand why it listed the long list....

That's just the hex representation of the data presented above. 0xB8 in decimal is 184 - the error number, 0x91 is the error type (istwert zu gross = sensor value too high), 0x24 and 0x28 are Error Frequency and Logistics Counter respectively and the remaining bytes are the 5x values recorded for each of instances 1 to 3. first 4 values are bytes and the 5th is a word.

[Pklauser]

Really wish I was coming back with better news. This remains unsolved. Been to two more track events where this has been pissing in my cheerios. One event it actually didn't crop up at all, another it didn't crop up til the end. I don't trust the car, which really sucks, and I'm starting to run out of ideas.

Let me recap everything that's been done over the last two years chasing this (in loose chronological order):

• Re-soldered original VANOS solenoid pack.
  • This fixed the code 72 that was appearing immediately on startup.
• Replaced VANOS solenoid pack with new OEM unit from FCP.
  • When the code 72 came back, I decided to forego my DIY solenoid repair.
• Validated VANOS solenoid wiring to the DME is good.
• Physically re-timed engine and made sure it was spot-on.
  • Did not remove VANOS unit to torque hub bolts.
  • Also did not double check cam bolts underneath hubs. I know the PO upgraded them to the new torx-bolts, but that's all I know.
• Replaced intake cam sensor with VNE unit.
• Replaced VANOS pump unit with new OEM unit upgraded by and purchased from Beisan.
  • This fixed a legitimate and confirmed oil pressure issue.
• Replaced intake cam sensor with BMW unit.
  • Learned that this is identical to the BMW unit, good use of funds, but here I am.
• Validated that the intake cam sensor wiring to the DME is good, <0.5 ohm resistance.

Continuing On

I reached out to Lama from Beisan systems, RIP Raj, to see what she thinks. She's had me go through some troubleshooting, but nothing that wasn't already tried in this thread: cleaning connectors, running the car at various RPMs for various intervals and seeing when the codes reappeared. Interestingly she operates completely with generic OBD codes, I'd think the BMW-specific codes would give more info, but I suppose not everyone calling in has that information. My OBD code is P0010. She suspected the VNE intake cam sensor to be bad, since it's not Genuine BMW, so I bought a Genuine BMW one, only to find that it's identical to the VNE part. The VNE part just has the BMW letters ground off. It sounds like she'll want to send me a Beisan solenoid pack next. We'll see how it shakes out, since the current solenoid pack only has maybe 5k miles on it.

Just got TestO downloaded, haven't hooked it up to the car yet, but it looks like it may be able to provide some insights into expected/actual cam angles, which I haven't been able to view with any other tools thus far. Will play around and report back on that.

Grasping at Straws

Is it possible this code is a big fat red herring? Everything has been pointing to the intake cam, so that's where all of my focus has been. Is it possible that exhaust cam sensor issues could throw the code 72 for some wild reason? I ask because I drove around with the solenoid completely unplugged, and all the INPA codes I got were related to the inlet cam, so it's almost like it just didn't care about the exhaust cam.

[sapote]

P0010 points to the vanos module having problem of moving the cam to the commanded angle. You have replaced all mechanical parts, so I think the two wires going from DME to the solenoid pack that controls the intake piston. check the wires to pins connection, even add solder to the wire/pin connection.

DME 52pin connector pin4 to solenoid p3;
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;p50 to ------------p1.

[Pklauser]

Yep, been checked for continuity on all the pins in the connector to the DME and they were all good. I made sure to wiggle the wires while checking as well. I can always check again.

[Pklauser]

Alright checked wiring again tonight. Everything is good, resistance < 0.5 ohm on all six wires to the DME.

Did find one interesting thing though: I checked each terminal to see how well it was "grabbing" the pins on the solenoid. Pin 1's terminal was pretty loose. I bent the top of it down with a pick to give it a little more "bite" on the pin. We'll see if that improves anything.

[sapote]

Alright checked wiring again tonight. Everything is good, resistance < 0.5 ohm on all six wires to the DME.

Did find one interesting thing though: I checked each terminal to see how well it was "grabbing" the pins on the solenoid. Pin 1's terminal was pretty loose. I bent the top of it down with a pick to give it a little more "bite" on the pin. We'll see if that improves anything.

I will do this and using the Ampmeter to measure the current to each solenoid and compare, they should be the same: apply 12v directly to each pin at the DME connector (unplugged from DME) and measure the current: p50, p4, p43, p44. Don't power the solenoid more than 30sec to avoid overheating.