P0307 on 2011-2016 BMW M5: Cylinder 7 Misfire Causes and Fixes

What's Unique About the 2011-2016 BMW M5

The S63 engine in the F10 M5 is a 'hot-vee' design, meaning its twin turbochargers are located in the valley between the cylinder banks. This layout creates immense heat that is notorious for accelerating the failure of plastic and electronic components located nearby, such as ignition coils and wiring. Consequently, ignition coils, fuel injectors, and various seals are common failure points leading to misfires. While a misfire on many cars is a simple fix, on the S63 it can often be a symptom of more significant, well-documented issues like failing direct fuel injectors. These injectors are a particularly weak point on earlier models, leading BMW to issue multiple updates and a 10-year/120,000-mile extended warranty for this component on many affected vehicles.

Symptoms You May Notice

• Rough or vibrating idle
• Engine hesitation or stumbling during acceleration
• Noticeable loss of power
• Flashing or solid Check Engine Light (or 'Drivetrain Malfunction' message on the iDrive screen)
• Increased fuel consumption
• Smell of gasoline from the exhaust
• Misfire is most noticeable on a cold start and may clear after the engine warms up

Most Likely Causes

1. Faulty Ignition Coil 🔴 High Probability → Shop Ignition Coil The 'hot-vee' engine design subjects the coils to extreme heat, causing the plastic and internal electronics to degrade and fail prematurely. This is a very common failure point across all S63/N63-powered vehicles.
   How to confirm: Swap the ignition coil from cylinder 7 with another cylinder (e.g., cylinder 8). Clear the codes and drive the car. If the misfire code changes to P0308, the ignition coil is faulty. This is a standard and effective diagnostic step confirmed by many owners in forums.
   Typical fix: Replace the faulty ignition coil. It is often recommended to replace them in a full set of 8 if they are original or old to ensure balanced performance and prevent future failures. Many owners on forums prefer the updated Eldor brand coils over the older Bosch or Delphi versions, citing better reliability.
   Est. part cost: $30-$80 per coil
2. Worn or Fouled Spark Plug 🔴 High Probability → Shop Spark Plug High cylinder pressures from the turbochargers and potential oil/fuel contamination shorten spark plug life. Oil from common valve seal leaks can foul the plug, preventing a spark. A fuel-soaked plug can also indicate a leaking injector.
   How to confirm: After ruling out the coil, remove the spark plug from cylinder 7. Inspect it for a worn electrode, carbon buildup, or contamination by oil or fuel. A wet or black-looking plug is a clear sign of a problem. An oil-fouled plug points towards valve stem seals, while a fuel-soaked plug points towards a leaky injector.
   Typical fix: Replace the spark plug. If one is worn, it's best practice to replace all 8. Ensure the new plugs are gapped correctly and torqued to the manufacturer specification of 23 Nm.
   Est. part cost: $15-$25 per plug
3. Faulty Fuel Injector 🔴 High Probability → Shop Fuel Injector The high-pressure direct fuel injectors on the S63 engine are a widely documented failure point, especially on pre-2013 models with injectors below 'Index 12'. They can become clogged or stuck open/closed, often leading to cold-start misfires that clear up when warm. This issue was so prevalent that BMW extended the warranty on injectors for many S63/N63 vehicles to 10 years or 120,000 miles.
   How to confirm: This is difficult for a DIYer. If swapping the coil and plug does not move the misfire from cylinder 7, the injector is the next logical suspect. A professional can perform a flow test. A strong smell of fuel from the oil filler cap or seeing puddles of fuel on the piston crown with a borescope are signs of a leaking injector. BMW's diagnostic software (ISTA) can also be used to shut off individual injectors to confirm the fault.
   Typical fix: Replace the fuel injector. BMW specifies that injectors must be of the same or a compatible index number per bank (cylinders 5-8). This often means replacing all 4 injectors on that bank, or even all 8, to ensure proper function. New injectors must be coded to the DME using software like ISTA to input their specific flow values. This is a costly repair.
   Est. part cost: $400-$600 per injector, or $2000-$5000 for a bank or full set

Rare But Worth Checking

• Leaking Valve Stem Seals: This is a very common problem on the S63/N63 engine family, often appearing after 60,000-80,000 miles. It causes high oil consumption and blue/white smoke from the exhaust after idling. The oil leaks onto the spark plug, fouling it and causing a misfire. If you have a misfire and are adding more than 1 quart of oil every 1,000 miles, this is a likely underlying cause. The repair is labor-intensive, often costing thousands of dollars.
• Failed Crankcase Vent (PCV) System: A failed PCV diaphragm or cracked vent hose can create a vacuum leak and cause the engine to pull excess oil into the intake manifold, which can foul spark plugs and lead to misfires and excessive smoke. These plastic hoses become brittle from engine heat.
• Low Compression: This is a worst-case scenario indicating a mechanical engine problem like a bad valve, piston rings, or scored cylinder walls. A leaking injector can wash oil from the cylinder walls, leading to scoring and loss of compression. A compression test is needed to confirm this after all other causes are ruled out.

Diagnosis Steps

1. Read the fault codes with a BMW-compatible OBD-II scanner to confirm P0307 and check for any other codes. Note any 'Drivetrain Malfunction' messages.
2. Identify Cylinder 7: On a LHD car, it is the third cylinder from the front bumper on the driver's side (Bank 2).
3. Swap the ignition coil from cylinder 7 with cylinder 8 (the rearmost on the same side). Clear the codes, run the engine, and see if the fault moves to P0308. If it does, the coil is bad.
4. If the misfire remains on cylinder 7, swap the spark plug from cylinder 7 with cylinder 6. Clear codes, run the engine, and see if the fault moves to P0306. If it does, the spark plug is bad.
5. While the spark plug is out, inspect it. Is it black and sooty (fuel fouled)? Is it wet and black with oil (valve seals/PCV)? This provides critical clues to the root cause.
6. If the misfire still stays on cylinder 7, the fuel injector is the most likely cause. This step is best left to a professional or advanced DIYer due to the high-pressure fuel system and coding requirements. Check service history for injector replacements under the extended warranty.
7. If the injector is confirmed good, check for underlying issues like valve stem seals (look for smoke after idling, high oil consumption) or PCV system leaks.
8. As a final step, a compression test and cylinder leak-down test should be performed to check for mechanical engine issues like worn piston rings or valve problems.

Parts You'll Likely Need

• Ignition Coil (OEM #12138647689 (Bosch), 12138657273 (Eldor)) — It is the most common and easiest-to-fix cause of a single-cylinder misfire on the S63 engine due to heat degradation.
  Trusted brands: Bosch, Delphi, Eldor
  OEM price range: $50-$80
  Aftermarket price range: $30-$60
• Spark Plug (OEM #12120039634) — A primary ignition component that is a regular wear item and is often the second part to check after the coil.

Related Codes That Often Appear With This One

• P0300 — If multiple components are failing (e.g., several injectors or coils), a P0300 'Random/Multiple Cylinder Misfire' code may appear alongside P0307.
• P0305, P0306, P0308 — Misfires on other cylinders in the same bank (Bank 2) can indicate a problem common to that bank, such as a fuel delivery issue, a shared VANOS solenoid problem, or multiple failing injectors on that bank.
• 2B3D, 2B3E, 2B3F, 2B40 — These are BMW-specific codes for 'Misfire with fuel cut-off' on cylinders 5, 6, 7, and 8 respectively. They often appear with the generic P030x codes and indicate the DME has shut off the injector to protect the catalytic converter.

Technical Service Bulletins (TSBs) & Recalls

• SI B13 08 15: Service Action for E70/E71 with S63 engine, instructing dealers to check and replace any fuel injectors with an index lower than 11.
• SI B01 06 18 / SI B01 03 15: Details the extended limited warranty for fuel injectors on certain models to 10 years/120,000 miles.
• SI B13 07 12: Outlines replacement procedures for N63/S63 high-pressure fuel injectors, noting that injectors with Index 11 or higher have improved construction and cannot be mixed with older injectors on the same bank.
• SI B11 13 14: Details the Customer Care Package for N63 engines which addresses oil consumption, but many of the root causes (valve seals, PCV) are shared with the S63.

Platform-Specific Known Issues

• The 'hot-vee' engine design leads to chronic heat damage of ignition coils and fuel injectors.
• Early production S63 engines (approx. 2011-2013) are highly prone to premature fuel injector failure. BMW has updated the injectors several times; the latest reliable version is known as 'Index 12' or higher.
• A warranty extension for fuel injectors was issued for many S63-powered vehicles, covering them for 10 years or 120,000 miles.

Mechanic-Grade Diagnostic Values

• Low-Pressure Fuel Pump (LPFP) Pressure — expected: Approximately 5 BAR or 72.5 PSI at idle.. Failure: Significantly lower pressure indicates a failing LPFP or clogged filter, which can starve the high-pressure pumps.
• High-Pressure Fuel Pump (HPFP) Rail Pressure — expected: Target pressure is around 124-200 BAR (1800-2900 PSI) under load. The system is capable of up to 250 BAR.. Failure: A reading that fails to meet the target, such as 83 BAR when 124 BAR is requested, points to a failing HPFP for that bank. This can cause misfires under load.
• Engine Compression — expected: While exact OEM specs are not commonly published, healthy S63 engines should show consistent readings across all cylinders, typically in the 150-180 PSI range. A reading of 120 PSI was considered low by one owner.. Failure: A cylinder reading that is 15-20% lower than the others indicates a mechanical problem (rings, valves, head gasket).

Hidden / Shadow Codes Worth Checking

• 2B3F: Misfire with fuel cut-off, cylinder 7. This is the direct BMW fault code that triggers the generic P0307 and confirms the DME has disabled the injector to protect the catalytic converter. (see via BMW-specific diagnostic software like ISTA, INPA, or a high-end scanner like Autel or BimmerGeeks ProTool.)
• 2EFF: An alternate BMW-specific fault code for 'Misfire, cylinder 7'. It is the underlying DME code that directly corresponds to the generic P0307. (see via BMW-specific diagnostic software like ISTA or INPA.)

Scan Tool Commands That Help

• ISTA: Injector Determination (Service Function) — Crucial before ordering new injectors on 2013-2014 models. Due to a mid-cycle change, this function confirms if the engine requires the earlier EU5 (piezo) or later EU6 (solenoid) type injectors, as they are not interchangeable. The path is Vehicle Management -> Service Functions -> Powertrain -> Engine Electronics -> Injector Determination.
• ISTA / ProTool / Autel: Injector Coding / Calibration — This is a mandatory step after replacing any fuel injector. Each new injector has a unique flow calibration value printed on it that must be entered into the DME. Failure to code the new injector will lead to incorrect fueling, poor performance, and persistent misfires.
• ISTA: Misfire Analysis Test Plan — When diagnosing a persistent misfire, this guided fault-finding plan in ISTA will run a series of checks and provide context-specific advice, such as swapping components and analyzing live data, to systematically isolate the root cause.

Wiring & Ground Locations

• Engine-to-Chassis Ground Strap (Transmission) — On the F10 chassis, a primary powertrain ground strap connects from the rear of the transmission case to a stud on the transmission tunnel/floor pan.. Corrosion or looseness of this main ground can cause a huge range of electrical gremlins, including weak spark, erratic sensor readings, and slow cranking, which can mimic other component failures.
• Engine Mount Ground Strap — A secondary ground strap is often found connecting the engine block to the chassis near one of the engine mounts.. Provides a redundant ground path for the engine. If the primary strap fails, this one becomes critical. Its failure can also lead to poor grounding and electrical issues.
• Valve Cover Ground Strap — A smaller, braided ground strap (PN 12427581396, superseded by 12428643430) connects the valve cover to the chassis.. This strap is specifically for grounding the ignition coils and reducing radio frequency interference. A faulty strap could potentially cause erratic coil behavior and contribute to misfires.

Real Owner Repair Stories

• Bimmerpost user (F10 M5, year not specified) — Cold start misfires that would disappear after the engine warmed up and was restarted.
  ❌ Tried (didn't work) Clearing codes, which would work temporarily until the next cold start.
  ✅ What actually fixed it The owner used a borescope to inspect the cylinders after the car sat and found puddles of raw fuel on the piston crowns. This confirmed leaking injectors. Replacing all 4 injectors on the affected bank and new spark plugs permanently solved the issue.
• YouTube user 'Wills Garage' (F10 M5) — Rough idle and 'Drivetrain Malfunction' error immediately after replacing all spark plugs and ignition coils. Scan showed misfires on cylinders 2, 3, and 4.
  ❌ Tried (didn't work) Initial visual inspection showed nothing wrong.
  ✅ What actually fixed it The electrical connectors for the new ignition coils were not fully seated. The locking tab on the coil can close even if the connector isn't pushed in all the way. The fix was to go back to each coil and push the connector firmly until it audibly clicked into place.

OEM Part Supersession History

• Various PNs with Index 10 or lower → 13538648937 (Index 11+) — Early index injectors (10 and below) had a high failure rate. BMW released updated injectors (Index 11, then 12) with improved internal construction and calibration to fix reliability issues.
  Heads up: CRITICAL: Injectors with Index 10 or lower CANNOT be mixed on the same engine bank (1-4 or 5-8) with injectors that are Index 11 or higher. Doing so will cause running issues due to different calibrations.
• EU5 Injectors (e.g., Bosch 0261500136) → EU6 Injectors (e.g., Bosch 0261500262) — Change in emissions standards and engine update (S63 to S63TU). The LCI models from mid-2013 onward use a completely different solenoid-type (EU6) injector.
  Heads up: EU5 (piezo) and EU6 (solenoid) injectors are not physically or electronically compatible. Installing the wrong type will not work. Use ISTA's 'Injector Determination' function to confirm which type your vehicle needs before purchasing.

Model Year Variations Within This Range

• 2011-mid-2013 (Pre-LCI): These models use the S63 engine with 'Index' style piezo fuel injectors (up to Index 12). They are highly prone to the injector failures covered by BMW's extended warranty. They also have an older iDrive system and steering wheel design.
• mid-2013-2016 (LCI): These models use the updated S63TU engine. The most significant change for this fault code is the switch to more reliable EU6-compliant solenoid-type fuel injectors, which are not interchangeable with the earlier style. These cars also feature updated headlights/taillights, a new steering wheel, and a newer iDrive system. The Competition Package was also introduced.

Diagnostic Flowchart

Other Known Issues on This Vehicle

Issues unrelated to this code that are worth knowing about as an owner of this generation:

• Connecting Rod Bearing Failure 🔴 High — Can occur randomly even on well-maintained cars, sometimes as early as 50-70k miles. Risk is increased by leaking injectors diluting the engine oil.
• Valve Stem Seal Degradation 🔴 High — Very common, typically starting between 60k-100k miles. Leads to high oil consumption and blue smoke from exhaust after idling. (Ref: SI B11 04 15 (Procedure Video))
• Excessive Oil Consumption 🟠 Medium — Common across the N63/S63 family. Often a symptom of failing valve stem seals or PCV system issues. Consumption over 1 quart per 1000 miles indicates a problem. (Ref: N63 Customer Care Package (SI B11 13 14) addresses this on the non-M engine, but root causes are similar.)
• Leaking Turbo Coolant Lines 🟠 Medium — The rubber sections of the turbo coolant lines become brittle and leak over time due to extreme heat in the engine valley. A known issue on all F10 M5s. (Ref: A service campaign was issued, but failures can still occur.)
• Carbon Buildup on Intake Valves 🟡 Low — A consequence of direct injection. Recommended to be cleaned via walnut blasting every 50k-70k miles on earlier S63 engines to prevent rough idle and power loss.

Used vs. New Parts: Buying Guide for This Vehicle

When a used part is the smart pick: For this repair, using used parts is generally not recommended for the primary failure items. A used ignition coil could be considered if it's a known good, low-mileage part from a reputable source, but new aftermarket coils are affordable. Used structural or cosmetic parts are fine, but not core ignition or fuel components.

Donor-vehicle mileage cap: roughly under 50000 miles for the part to have meaningful remaining life.

What to inspect on the donor part:

• For a coil, check for cracks in the plastic housing or corrosion on the electrical connector.
• Verify the part number and brand (e.g., Bosch, Eldor) to ensure it's not a cheap knock-off.
• Ask for the donor vehicle's VIN to check its production date and mileage.

OEM-only on this vehicle (don't cheap out):

• Fuel Injectors: This is the most critical part to buy new from a reputable source (OEM BMW or OEM supplier like Bosch). Used injectors are a huge gamble due to the high failure rate, unknown history, and complex indexing/coding. Fake 'Index 12' injectors are common on marketplace sites.
• High-Pressure Fuel Pump (HPFP): Given the labor to replace, a new OEM (Bosch) or Genuine BMW pump is the only wise choice to ensure reliability.

Aftermarket brands forum-validated for this vehicle:

• Ignition Coils: Eldor, Bosch, Delphi are all OEM suppliers and considered reliable choices.
• Spark Plugs: NGK (OEM supplier) is the standard recommendation.

Brands owners have reported issues with on this vehicle:

• Any unbranded fuel injectors or ignition coils from online marketplaces (e.g., eBay, Amazon). They are often counterfeit or low-quality and will likely fail quickly, causing more diagnostic headaches.

Real Owner Stories

Aggregated from forums and TSBs cited above. Mileages and costs reflect what owners reported in those sources.

Related OBD-II Codes

• P0308 — Companion misfire code for the adjacent cylinder (Cylinder 8) on the same bank; often used during the 'swap test' to confirm a faulty ignition coil.
• P0306 — Misfire code for Cylinder 6; used as a diagnostic target when swapping spark plugs to verify if the fault follows the plug.
• P0300 — Random/Multiple Cylinder Misfire; often accompanies P0307 when multiple injectors or coils are failing due to heat soak in the 'hot-vee'.
• P0171 — Lean condition code that may trigger if a fuel injector is clogged or stuck closed on Bank 2.
• P0172 — Rich condition code that may trigger if a fuel injector is leaking or stuck open, often identified by a gasoline smell from the exhaust.

Frequently Asked Questions