What code 2A99 means
VANOS exhaust-side fault. On high-mileage engines this often means a worn exhaust cam phaser or oil-flow restriction in the exhaust-side VANOS circuit. Inspect oil pressure and quality before condemning the solenoid.
How to read a VANOS code
VANOS codes describe the variable valve-timing system. On BMW engines the intake and exhaust camshafts each have their own solenoid; a single-sided fault usually means a solenoid, while a both-sides fault usually means oil pressure, oil flow, or a stretched chain.
- Check oil level and quality first.
VANOS relies on clean oil at the right pressure. Low oil or worn oil is the most common upstream cause of VANOS codes.
- Read cam timing live.
Compare the actual intake and exhaust cam positions against the commanded values. If both are off, suspect the chain. If one is off, suspect that solenoid.
- Inspect the solenoid screens.
The VANOS solenoids have small intake screens that clog with varnish. Cleaning them is a routine maintenance item on higher-mileage engines.
- Check the duty cycle / current.
A solenoid that is being commanded but drawing no current is electrically open. One drawing full current and not moving is mechanically stuck.
Related codes in the same family
2A82 — VANOS intake control fault.
A DTC tells you what a control module decided is outside its expected range. It does not automatically identify a failed component. Read freeze frames, compare related codes, and inspect live data before changing parts. Service functions and coding operations are write paths — use a battery maintainer where the procedure requires stable voltage and never perform writes you do not understand.
2A99 questions
What does code 2A99 mean?
VANOS exhaust: control fault, camshaft stuck (community list).
Is 2A99 a BMW-specific code?
Yes — {code} is a BMW-specific fault code, not a generic OBD-II code.
How do I read 2A99 with Beemuu?
Connect on K+DCAN or ENET/DoIP, run a vehicle scan, and look up 2A99 in the fault list. Beemuu preserves the code, description and freeze frame before you clear anything.
What does the severity mean?
Critical means the code is usually associated with drivability or safety; warn means investigate soon; info means it is a state or condition rather than an outright fault.