P0021 on BMW: How to Diagnose & Fix
Intake Camshaft Position Timing - Over-Advanced or System Performance (Bank 2)
3 BMW models · 4 documented issues · 3 critical · $300-$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 (2)
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.
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Sources for this issue (3)
- BMW M5 (E39) PH Buying Guide - Powertrainbuying-guide
- Beisan VANOS Seals Repair Kit - E39 M5 S62parts-reference
- Beisan VANOS Rattle Repair Kit - E39 M5 S62parts-reference
The S85 V10 uses a high-pressure VANOS pump to supply the oil pressure that moves the variable valve timing units. The pump works at about 115 bar. The high-pressure VANOS oil lines can leak at the fittings where the rigid metal pipe ends join the flexible hose section. A leak loses oil and lowers the pressure available to the VANOS system, and a parts seller warns this can lead to very expensive engine damage. BMW issued a service bulletin (SIB 11 10 05) to replace the VANOS high-pressure line on M5s produced up to 11/22/05. Buyer guides report that a failed line can starve the pump of pressure, which can cause the pump to fail and send metal debris through the engine. How much the repair costs depends on whether that debris has contaminated the rest of the engine. Low VANOS system pressure is the telltale sign of a leaking line.
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
Check first: look for oil leaks around the VANOS lines at the front of the engine, and have a shop check VANOS system pressure. Low pressure points to a leaking line. On early cars (built up to 11/22/05), check the service records for the SIB 11 10 05 line replacement, and ask any seller for records of VANOS line inspection or replacement. Fix: replace the leaking line with the current genuine BMW part. 11 36 7 838 670 is the pressure hose that runs from the pressure accumulator to the VANOS units. 11 36 7 838 669 is the hose that runs from the high-pressure oil pump to the other pressure hose. When you replace a line, also replace the crush washers at each end (4 in total) and, on the 838 669 hose, the O-ring at the top. The banjo bolts are cheap and optional. Getting to the 838 669 hose means removing the oil pan, so it is often replaced at the same time as the rod bearings. If the pump has failed and shed metal debris, the rest of the engine needs to be checked for contamination. Fix a known VANOS line leak promptly rather than driving on it. A published buyer guide puts VANOS high-pressure pump failure at $3,000 to $32,000, depending on whether debris has contaminated the rest of the engine.
Call to confirm they can assess your vehicle and perform the stated work. Search results do not confirm qualification, eligibility or coverage.
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 (5)
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 works at up to roughly 115 bar (about 1,670 psi). Over time the pump's internal seals wear and the high-pressure VANOS lines can split, causing pressure to drop dramatically. 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 (2)
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 or System Performance (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 3 models: X6 M, M5, M6.
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 $300 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.
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Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.