P0012 on BMW: How to Diagnose & Fix
Intake Camshaft Position Timing - Over-Retarded (Bank 1)
7 BMW models · 8 documented issues · 4 critical · $100-$32,000 repair
P0012 on BMW by model: symptoms, diagnosis and fix
The N63 4.4L twin-turbo V8 engine in E71 (2008-2014) and F16 (2015-2018) X6 xDrive50i models suffers from premature timing chain stretch and guide failure. This is the same catastrophic issue affecting X5 xDrive50i. The plastic timing chain guides disintegrate from the extreme heat generated by the "hot-vee" turbocharger configuration where turbos sit between the cylinder banks. Timing chains stretch, guides crack and break, leading to chain jump or failure causing piston-to-valve collision and complete engine destruction ($15,000-25,000 replacement). BMW issued TSB B001314 in 2014 acknowledging the issue. Bimmerpost consensus: avoid 2008-2014 N63 models unless timing chain has been replaced with updated parts.
Common Symptoms
- Rattling noise from engine on cold starts (sounds like marbles in a tin can)
- Engine timing-related fault codes (P0016, P0017)
- Loss of power and sluggish acceleration
- Check engine light
- Engine failure or no-start condition (if chain fails completely)
- Catastrophic piston-to-valve collision
How to Fix
PREVENTIVE REPLACEMENT: If you own 2008-2014 E71 xDrive50i with N63, replace timing chain guides and tensioners IMMEDIATELY at 60,000-80,000 miles ($4,000-6,000) BEFORE failure. IWIS timing chain kit 90001521 ($800-1,200) or Turner kit 11317594899KT recommended. Replace lower chain guide 11147574373 at same time. If chain has already failed: complete engine replacement required ($15,000-25,000). Check VIN with BMW dealer for extended warranty eligibility. 2015+ N63TU engines have improved timing components but still require monitoring.
Sources for this issue (1)
The E70 and F15 xDrive50i use generation-specific N63 boost-control hardware. BMW's N63 training shows that the wastegate valves are moved by vacuum units through electropneumatic pressure converters; hoses, reservoir, vacuum pump, converters, actuator linkage, charge-air leaks, and the turbocharger/wastegate hardware can therefore create overlapping rattle or low-boost complaints. Rattle alone does not prove both turbochargers failed, and the previously listed P0011/P0012/P0014/P0016/P0017 are cam-timing faults rather than wastegate identifiers. The N63 Customer Care Package is not a Central Cooling Pump campaign and does not promise generic wastegate or turbo coverage.
Common Symptoms
- Rattle from the turbocharger or wastegate area
- Low boost or reduced engine power
- Turbo lag or inconsistent boost response
- Reduced-power mode with boost-control faults
How to Fix
Read all DME faults and compare requested versus actual boost under the BMW test plan. Pressure- or smoke-test the intake and charge-air path, verify vacuum supply from the pump and reservoir, inspect both banks' hoses and pressure converters, and test actuator movement before condemning a turbocharger. Identify the engine generation, failed bank, and exact hardware in BMW ETK/AIR. Check a 2010-2013 E70 VIN for the N63 Customer Care Package only as applicable; its published six-point scope includes air-mass sensors, injectors, vacuum pump, low-pressure fuel sensor/feed line, fresh-air turbo seals, and crankcase-ventilation lines, not an automatic wastegate replacement. No retail link is published until diagnosis selects a VIN-specific component.
Owner tips & cautions
- TipAsk the shop to identify the failed bank and show vacuum, pressure-converter, actuator-travel, and requested-versus-actual boost results before authorizing turbo parts.
- WarningDo not order a universal Garrett actuator from a rattle or low-boost message; E70 and F15 N63 systems use generation- and VIN-specific hardware.
Sources for this issue (3)
The N55 3.0L turbocharged inline-6 engine in 435i and early 440i models experiences VANOS (Variable Valve Timing) solenoid failures. These solenoids control oil flow to the VANOS system for variable valve timing. Internal wear causes them to stick or fail, leading to rough running, power loss, and check engine lights. The intake VANOS solenoid (cylinder head front) fails more frequently than the exhaust solenoid. Oil contamination and sludge accelerate failure. This is a common issue shared with N55-powered 335i, 535i, and X5 35i models.
Common Symptoms
- Rough idle or engine stumble
- Check engine light with VANOS codes (P0011, P0012, P0021, P0022)
- Loss of power or poor throttle response
- Increased fuel consumption
- Cold start rough running that improves when warm
How to Fix
Replace failed VANOS solenoid(s). Both intake and exhaust solenoids should be inspected. Clean VANOS system if contaminated with sludge. Use high-quality full synthetic oil (BMW LL-01 spec) and maintain 7,500-mile oil change intervals to prevent premature failure. Some shops recommend replacing both solenoids preventively.
What you need to fix it
Only diagnosis- and fitment-reviewed repair parts are linked here.
- Genuine BMW N55 VANOS solenoid valve 11368605123OEM11368605123
BMW catalogs quantity two but replace only the diagnosed failed position unless the repair plan calls for both; confirm VIN..
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 N20 2.0L turbocharged engine in 428i models suffers from premature timing chain stretch and guide failure, typically occurring between 40,000-80,000 miles. The single-row timing chain design is inadequate for the engine's power output. Chain stretch causes the timing to jump, leading to rough running, poor performance, and potential catastrophic engine damage if the chain breaks. BMW issued a class action settlement covering 8 years/100,000 miles. This is identical to the N20 timing chain issue in 328i/X3/X5 models using the same engine.
Common Symptoms
- Rattling noise from engine on cold start (first 5 seconds)
- Check engine light with timing correlation codes (P0016, P0017, P0018, P0019)
- Rough idle or misfires
- Loss of power or hesitation on acceleration
- Engine won't start after chain failure
How to Fix
Complete timing chain kit replacement including chain, guides, tensioner, and sprockets. Must be performed by experienced BMW technician. Preventive replacement recommended at 60,000-80,000 miles. BMW extended warranty to 8 years/100,000 miles under class action settlement. Upgraded reinforced chain kit available from aftermarket.
What you need to fix it
Only diagnosis- and fitment-reviewed repair parts are linked here.
- Iwis N20 timing-chain kit 11315A19AA2
Fitment: F32/F33/F36 BMW 428i and 428i xDrive with N20 as listed by Turner; use the vehicle selector and confirm VIN/production date. Kit lists chain, gaskets, guides/rails, sprocket and hardware; technician must confirm any additional o…
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 N63TU3 4.4L twin-turbo V8 in M850i models uses plastic timing chain guides that wear prematurely under the extreme heat and stress of the hot-V configuration. As the plastic guides wear, the timing chain develops slack, causing rattling on cold starts and eventually risking timing chain skip or failure. Chain skip causes piston-to-valve collision and catastrophic engine destruction ($15,000-$25,000 replacement). While the N63TU3 has improved guides over earlier N63 versions, the fundamental plastic guide material still degrades from heat cycling. Turner Motorsport offers a complete timing chain guide kit (11317594899KT) with all necessary components. Bimmerpost consensus: replace timing chain guides preventively at 80,000-100,000 miles on N63TU3 engines before catastrophic failure.
Common Symptoms
- Rattling noise from engine on cold starts (sounds like marbles in a tin can)
- Engine timing-related fault codes (P0016, P0017)
- Loss of power and sluggish acceleration
- Check engine light
- Rough idle that improves after warm-up
- Catastrophic engine failure if chain skips (no start, piston damage)
How to Fix
PREVENTIVE REPLACEMENT: Replace timing chain guides, tensioners, and chain at 80,000-100,000 miles ($4,000-$7,500). Turner Motorsport timing chain kit 11317594899KT includes all necessary components. Individual parts: chain guides 11147574373, 11317574397, 11317592850, 11317592877; chain 11317598263. If chain has already skipped: engine damage likely requires $15,000-$25,000 engine replacement. CRITICAL: If you hear cold-start rattling, do NOT drive - tow to shop immediately to prevent catastrophic engine failure.
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..
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)
P0012 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 P0012 mean on a BMW?
P0012 stands for "Intake Camshaft Position Timing - Over-Retarded (Bank 1)." This code means the intake camshaft timing on Bank 1 is more retarded than the computer commanded — the variable valve timing system isn't reaching its target position. The computer controls camshaft timing through an oil-fed actuator (cam phaser) and a control solenoid; when actual timing lags the desired setting, this code sets. It is commonly caused by oil flow problems (low, dirty, or wrong oil), a stuck solenoid, or a worn cam phaser. Symptoms can include rough idle, reduced power, poor fuel economy, and sometimes rattling on startup. On BMW it is documented across 7 models: X6, X5, 4 Series, 8 Series, M5, X5 M, Z4.
What are the most common causes of P0012?
The most common causes of P0012 are: Low, dirty, or incorrect-viscosity engine oil, Faulty or stuck intake camshaft (VVT) oil control solenoid, Worn or stuck camshaft phaser/actuator, Clogged solenoid screen or oil passages, Wiring or connector problems at the solenoid, Timing chain wear or stretch affecting cam timing, Faulty camshaft position sensor. The specific cause varies by vehicle.
How much does it cost to fix P0012 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 P0012 on a different make?
View P0012 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.