P0021 on BMW: How to Diagnose & Fix
Intake Camshaft Position Timing - Over-Advanced (Bank 2)
6 BMW models · 7 documented issues · 4 critical · $100-$32,000 repair
P0021 on BMW by model: symptoms, diagnosis and fix
The S63 twin-turbo V8 in the X6 M relies on VANOS variable valve timing solenoids that are sensitive to oil quality. Sludge buildup from extended oil change intervals or short-trip driving restricts oil flow to the solenoids, causing rough idle and reduced power.
Common Symptoms
- Rough idle especially when cold
- Reduced engine power
- Check engine light
- Engine stumble on acceleration
- Ticking noise from valve covers
- Poor fuel economy
How to Fix
Remove and clean or replace the VANOS solenoids. Perform an engine oil flush. Strictly follow 7,500-mile oil change intervals with BMW LL-01 rated 0W-40 synthetic oil.
Sources for this issue (1)
The VANOS (Variable Valve Timing) system on all E85 and E89 Z4 engines (M54, N52, N54, N20) suffers from solenoid failures, typically beyond 100,000 miles. The VANOS solenoids control oil flow to the variable camshaft timing adjustment units, and they fail through three primary modes: solenoid coil pack malfunction, sticking solenoid valves from oil varnish buildup, and deteriorating solenoid sealing plate rubber rings. When VANOS solenoids fail, the engine loses its ability to optimize valve timing, causing rough idle, power loss, poor fuel economy, and unusual engine noises. Z4-forum.com documents this as an extremely common issue across all E85 and E89 models. The good news: VANOS solenoids are inexpensive and relatively easy to replace - one of the simpler E85/E89 repairs.
Common Symptoms
- Rough or uneven idle with RPM fluctuations
- Noticeable loss of power during acceleration
- Engine misfires causing hesitation or jerking
- Rattling, ticking, or clicking noises from engine (especially at startup)
- Increased fuel consumption (10-15% higher than normal)
- Check engine light with VANOS-related fault codes (2A82, 2A87, 2A9A, 2A9F)
How to Fix
Replace VANOS solenoids - inexpensive and straightforward repair. M54 (E85 2003-2005): 2 solenoids required, BMW 11361707323 ($35-$65 each). N52 (E85 2006-2008 / E89 2009-2011 28i): 2 solenoids, BMW 11367585425 ($40-$70 each). N54 (E89 35i/35is): 2 solenoids, BMW 11367585425 ($40-$70 each). N20 (E89 sDrive28i 2012-2016): 2 solenoids, BMW 11367585425 ($40-$70 each). Labor: under 1 hour for experienced mechanic, 2-3 hours DIY. Replace all solenoids at once even if only one has failed - the others are same age and will fail soon. Also replace VANOS solenoid O-rings and sealing plates during service. Clean VANOS system with Beisan Systems VANOS cleaning procedure for best results.
What you need to fix it
Only diagnosis- and fitment-reviewed repair parts are linked here.
- Beisan BS001 double-VANOS seals repair kit
M54 internal double-VANOS seal repair after confirmed seal degradation. Confirm engine and internal VANOS diagnosis before ordering..
- Genuine BMW N52/N54 VANOS solenoid valve 11367585425OEM11367585425
Confirmed N52/N54 intake or exhaust VANOS solenoid replacement. Replace only the failed/test-confirmed unit or both when the repair decision specifically calls for it.
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Sources for this issue (1)
The E39 M5's S62 V8 commonly develops VANOS-related problems as mileage and age increase, especially from worn piston seals, leaking solenoid pack seals, and failing solenoids. Owners report cold-start rattle, reduced low-end torque, intermittent limp behavior, and check engine lights tied to cam timing deviations. This is a well-known E39 M5 issue discussed extensively in owner communities and supported by BMW service information covering VANOS fault diagnosis.
Common Symptoms
- cold start rattle
- check engine light
- loss of low-end torque
- rough idle
- hesitation under acceleration
- intermittent limp mode
How to Fix
Diagnosis typically includes scanning for camshaft timing and VANOS activation faults, checking oil condition/pressure, and listening for startup rattle from the front of the engine. Repair usually involves rebuilding the VANOS units with upgraded seals, replacing failed solenoids or solenoid seals, and correcting any oil leaks or timing-related wear. Many owners address both banks preventively while the front of engine is apart.
What you need to fix it
Only diagnosis- and fitment-reviewed repair parts are linked here.
- Beisan BS064 S62 upgraded solenoid O-ringsCross-refBS064, 11367830828, 11367830829
Solenoid seal repair component. Fitment: US-market 2000-2003 E39 M5 S62; one BS064 set covers both solenoid banks.
As an Amazon Associate, we earn from qualifying purchases; other part links may also earn au7o a commission. Confirm fitment by VIN before buying.
Sources for this issue (1)
The S85 engine uses high-pressure VANOS (Variable Valve Timing) pump to supply necessary hydraulic pressure. The high-pressure VANOS lines were improperly routed without adequate bends to attach to VANOS pump, causing premature line failure and oil leaks. When VANOS line fails and leaks, it can starve VANOS pump of pressure, causing pump failure and sending metal debris throughout engine. This can escalate to CATASTROPHIC engine damage requiring complete engine replacement ($32,000). BMW settled class action lawsuit regarding VANOS failures and agreed to cover repairs for owners who reported issues before settlement cutoff date. M5Board warns: DO NOT ignore VANOS line leaks - this can destroy entire engine within weeks.
Common Symptoms
- Rough idling and unstable idle speed
- Reduced power output and poor acceleration
- Poor fuel economy
- Rattling or grinding noise from engine bay at startup
- Oil leaks visible near front of engine (VANOS area)
- Check engine light with VANOS-related fault codes
How to Fix
Replace high-pressure VANOS line with updated design that includes proper bend radius ($3,000 parts + labor). Replace VANOS high-pressure pump if showing signs of wear or contamination. DrVanos offers fully rebuilt S85 VANOS pumps ($1,800 + $400 core deposit) - M5Post gold standard for rebuilds. This repair is BEST performed simultaneously with rod bearing replacement to save on overlapping labor costs ($2,000-$4,000 savings). WARNING: DO NOT ignore VANOS line leaks - metal debris from failed pump circulates through entire lubrication system and can destroy engine. If catastrophic failure: engine replacement required ($32,000).
What you need to fix it
Only diagnosis- and fitment-reviewed repair parts are linked here.
- Genuine BMW S85 VANOS oil line 11367838669OEM11367838669
The retailer specifies four 07119963129 copper washers and one 11367834552 O-ring as additional required items; verify VIN and the exact failed line..
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Sources for this issue (1)
The N63 twin-turbo V8 places the turbos inside the vee, and the trapped heat cooks the plastic timing chain guides until they crack and break apart. Debris from a shattered guide lets the chain go slack, so it stretches, throws timing correlation codes, and can jump a tooth - at which point one whole bank stops firing and the driver gets a Drive Train Malfunction with reduced power. Owners on the F01 chassis have reported broken guides and a jumped chain around 100,000-120,000 miles, often preceded for months by a rattle or grinding noise during the first few seconds after a cold start. Early N63 engines (roughly 2009-2013) were the worst and were covered in part by the Customer Care Package rework.
Common Symptoms
- Rattle or grinding for a few seconds at cold start
- Drive Train Malfunction warning
- One bank of cylinders stops firing
- Rough running and severe loss of power
- Check engine light with timing correlation codes
How to Fix
Do not ignore a cold-start rattle on an N63. Pull the DME for timing correlation codes and check the chain wear with a scope before it jumps. The repair replaces the complete kit - chains, guides, tensioners and sprockets on both banks - because reusing any one worn part causes a repeat failure. The engine has to come out and be largely disassembled; it is roughly a 40-hour job, which is why quotes land in the five-figure range at a dealer. If the chain has already jumped, the valves may be bent and the heads need inspection.
Sources for this issue (3)
On the S85 5.0L V10 (E63/E64 M6), the VANOS variable-valve-timing system runs off a dedicated high-pressure oil pump mounted in the oil pan that must produce roughly 1,000 psi. Over time the pump's internal seals wear and the high-pressure VANOS lines can split, causing pressure to drop dramatically (owners have measured as low as ~180 psi against the ~1,000 psi spec). The pump can eventually disintegrate, contaminating the engine with debris. This is a distinct failure from rod-bearing wear and is one of the most expensive non-bearing repairs on the V10. Left unaddressed it can cause valvetrain and broader engine damage.
Common Symptoms
- Knocking/rattling noise from the cam hubs while cranking
- Gentle knocking from the front of the cylinder heads while running
- Jerky power delivery at low RPM
- Loss of high-RPM performance / rough running
- VANOS fault codes / Check Engine Light
How to Fix
Perform an oil-pressure test on the VANOS circuit at the first sign of cold-start knocking. Replace or professionally rebuild the high-pressure VANOS pump and renew the high-pressure lines/seals. Many owners do the VANOS pump preventively at the same time as the rod-bearing service since the oil pan is already removed. Use only BMW-spec oil and strict change intervals to prolong pump life.
Sources for this issue (1)
P0021 code reference
General diagnostic-code context. The code alone does not confirm a cause for your vehicle; use the applicable issue card and its sources.
Frequently asked questions
What does P0021 mean on a BMW?
P0021 stands for "Intake Camshaft Position Timing - Over-Advanced (Bank 2)." P0021 means the engine computer detected that the intake camshaft on bank 2 is timed too far advanced and won't return to its commanded position. Most modern engines use variable valve timing (VVT), where an oil-pressure-driven actuator rotates the camshaft to optimize power and efficiency; the PCM compares the camshaft's actual position to its target. When the cam stays over-advanced beyond an acceptable limit, this code sets. Bank 2 refers to the side of the engine that does not contain cylinder number one. You may notice rough idle, reduced performance, or lower fuel economy. On BMW it is documented across 6 models: X6 M, Z4, M5, 7 Series, M6, 4 Series.
What are the most common causes of P0021?
The most common causes of P0021 are: Dirty or low engine oil restricting the VVT system, Stuck or failed camshaft oil control valve (VVT solenoid) on bank 2, Clogged VVT solenoid screen or oil passage, Faulty camshaft position actuator / phaser, Wiring or connector fault at the VVT solenoid, Camshaft or crankshaft position sensor problems, Worn timing chain, guides, or stretched chain altering cam timing. The specific cause varies by vehicle.
How much does it cost to fix P0021 on a BMW?
Published repair estimates on BMW range from $100 to $32,000 depending on the model and root cause. If an issue mentions a recall or campaign, check your VIN with the manufacturer or NHTSA and confirm eligibility and coverage with a dealer.
Looking for P0021 on a different make?
View P0021 across all makes →Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.