The P0311 OBD-II trouble code means the engine control module has detected a combustion misfire associated with Cylinder 11.
Unlike P0300, which indicates random or multiple-cylinder misfires, P0311 identifies one specific cylinder. That narrows the diagnosis, but it does not prove that the Cylinder 11 ignition coil has failed.
A worn spark plug, weak ignition coil, defective fuel injector, damaged electrical circuit, intake leak, low compression, or valvetrain problem can all trigger P0311.
The computer knows Cylinder 11 contributed less power than expected. It does not know which component should be replaced. Apparently, even a V12 remains stubbornly opposed to convenient assumptions.
P0311 belongs to the misfire-code family covered in the complete Pro Street P-code OBD-II guide.
P0311 Quick Answer
| Item | Information |
|---|---|
| Trouble code | P0311 |
| Definition | Cylinder 11 Misfire Detected |
| System | Ignition and combustion |
| Severity | High |
| Safe to drive? | Only briefly if the engine runs smoothly and the Check Engine Light is not flashing |
| Most common causes | Spark plug, ignition coil, injector, wiring, intake leak, or low compression |
| Common applications | V12 and W12 engines |
| Related codes | P0211, P0361 and P0300 |
| Typical repair range | Approximately $100 to $15,000+, depending on the vehicle and cause |
What Does the P0311 Code Mean?
P0311 breaks down as follows:
- P: Powertrain
- 0: Generic OBD-II code
- 3: Ignition or combustion misfire
- 11: Cylinder 11
The engine control module monitors slight changes in crankshaft speed during individual combustion events. A properly operating cylinder accelerates the crankshaft when combustion forces its piston downward.
When Cylinder 11 repeatedly produces less power than expected, the crankshaft momentarily slows. The control module recognizes this pattern and stores P0311.
Depending on the severity and frequency of the misfire, the Check Engine Light may remain steadily illuminated or begin flashing.
P0311 identifies the affected cylinder. It does not identify whether the failure involves:
- Spark
- Fuel delivery
- Airflow
- Compression
- Valve operation
- Mechanical timing
- Electrical control
For broader information about combustion failures, visit our engine misfire symptoms, causes and diagnosis guide.
Which Vehicles Can Store P0311?
P0311 only applies to engines with at least 11 cylinders.
Common configurations include:
- V12 engines
- W12 engines
- Certain specialty multi-cylinder engines
Applications may include some vehicles from:
- Audi
- Bentley
- Volkswagen
- BMW
- Mercedes-Benz
- Maybach
- Aston Martin
- Ferrari
- Lamborghini
- Rolls-Royce
The general P0311 definition remains consistent, but cylinder location, ignition design, fuel-injection system, access procedure, and test specifications vary significantly.
A code reader may identify Cylinder 11 in seconds. Reaching its spark plug on some vehicles may require considerably longer and a suspicious number of removed components.
Where Is Cylinder 11 Located?
Cylinder 11 location depends on the engine family and manufacturer’s numbering system.
On a V12 engine, Cylinder 11 may be:
- On either cylinder bank
- Near the front or rear of the engine
- Beneath an intake manifold
- Behind wiring or fuel-system components
- In a location requiring extensive disassembly
Some manufacturers place odd-numbered cylinders on one bank and even-numbered cylinders on the opposite bank. Others number the cylinders sequentially along each bank.
W12 engines use an even more complex arrangement that should only be identified using manufacturer-specific service information.
Before removing an ignition coil, spark plug, or injector, identify Cylinder 11 using:
- Factory service information
- Manufacturer repair manual
- Underhood emissions label
- Vehicle-specific firing-order diagram
- Correct engine identification code
Never assume Cylinder 11 is simply the eleventh coil you can see.
Testing the wrong cylinder wastes diagnostic time and can create an additional misfire if an unrelated connector or coil boot is damaged.
Common Conditions Associated With P0311
A Cylinder 11 combustion problem may cause:
- Illuminated Check Engine Light
- Flashing Check Engine Light
- Rough or unstable idle
- Engine shaking
- Hesitation
- Reduced acceleration
- Loss of engine power
- Hard starting
- Stalling
- Increased fuel consumption
- Raw fuel smell from the exhaust
- Failed emissions test
- Popping from the intake or exhaust
- Reduced turbocharger boost
- Limp mode
- Additional ignition, injector, or fuel-trim codes
A single-cylinder misfire may be difficult to feel on a V12 because the remaining cylinders can partially mask the loss of contribution.
The absence of violent shaking does not make P0311 harmless. Unburned fuel can still damage the catalytic converter, contaminate the engine oil, and increase emissions.
How Serious Is P0311?
P0311 should be treated as a high-priority trouble code.
An active misfire may send unburned fuel into the exhaust. That fuel can ignite inside the catalytic converter, causing the catalyst to overheat or melt.
Continued driving may contribute to:
- Catalytic converter damage
- Oxygen sensor contamination
- Cylinder-wall fuel wash
- Engine oil dilution
- Burned exhaust valves
- Piston damage
- Excessive engine vibration
- Reduced fuel economy
- Increased emissions
Stop Driving Immediately If:
- The Check Engine Light is flashing
- The engine shakes violently
- Power loss becomes severe
- The vehicle stalls
- A strong raw-fuel smell is present
- The engine overheats
- Mechanical knocking is heard
- Abnormal valvetrain noise develops
A flashing Check Engine Light generally indicates a catalyst-damaging misfire. Reduce engine load, pull over safely, and shut off the engine.
If the light remains steady and the engine runs reasonably smoothly, driving a short distance for diagnosis may be possible. Avoid heavy throttle, high RPM, towing, and boost.
Most Common Causes of P0311
Cylinder 11 can misfire because of an ignition, fuel, electrical, airflow, compression, or mechanical problem.
| Possible cause | Relative likelihood |
| Worn or fouled spark plug | Very high |
| Weak or failed ignition coil | Very high |
| Damaged coil boot or spark plug wire | High |
| Clogged or failed fuel injector | High |
| Coil or injector wiring fault | Medium |
| Intake leak near Cylinder 11 | Medium |
| Low Cylinder 11 compression | Medium |
| Oil or coolant in the spark plug well | Application dependent |
| Carbon buildup on an intake valve | Medium on direct-injected engines |
| Burned or leaking valve | Medium |
| Worn camshaft lobe or failed follower | Application dependent |
| Damaged piston ring | Lower |
| Head gasket failure | Lower |
| Incorrect valve timing | Lower |
| PCM driver failure | Rare |
The engine family, mileage, maintenance history, related codes, and freeze-frame conditions should determine the testing order.
How to Diagnose P0311
Step 1: Confirm P0311
Connect an OBD-II scanner and record:
- Stored codes
- Pending codes
- Permanent codes
- Freeze-frame data
- Cylinder-specific misfire counters
Do not erase P0311 before saving the freeze-frame information.
Record:
- Engine RPM
- Engine load
- Vehicle speed
- Coolant temperature
- Intake-air temperature
- Short-term fuel trim
- Long-term fuel trim
- Throttle position
- Fuel-system status
The operating conditions can provide important clues.
| When P0311 occurs | Possible diagnostic direction |
| Cold start | Injector leak, deposits, coolant intrusion, or weak compression |
| Warm idle | Intake leak, injector imbalance, or mechanical problem |
| Heavy acceleration | Weak coil, worn plug, excessive plug gap, or insufficient fuel |
| Wet weather | Coil boot, connector, or insulation damage |
| After heat soak | Ignition coil, injector, connector, or wiring fault |
| Constantly | Dead coil, failed injector, circuit problem, or low compression |
| After recent service | Loose connector, wrong plug, damaged boot, or installation error |
Step 2: Check for Related Trouble Codes
P0311 may appear with other misfire, ignition, injector, or timing codes.
Related codes include:
- P0300 — Random or Multiple Cylinder Misfire
- P0307 — Cylinder 7 Misfire
- P0308 — Cylinder 8 Misfire
- P0309 — Cylinder 9 Misfire
- P0310 — Cylinder 10 Misfire
- P0312 — Cylinder 12 Misfire
- P0171 or P0174 — System Too Lean
- P0172 or P0175 — System Too Rich
- P0211 — Cylinder 11 Injector Circuit Malfunction
- P0361 — Ignition Coil K Primary/Secondary Circuit Malfunction
- Camshaft or crankshaft position codes
- Fuel-pressure codes
- Valve-timing codes
Several cylinder-specific misfire codes may indicate a shared problem such as:
- Low fuel pressure
- Contaminated fuel
- Large vacuum leak
- MAF sensor error
- Incorrect valve timing
- Weak charging voltage
- Poor engine ground
- Shared coil or injector power-supply failure
- Crankshaft position signal fault
Step 3: Determine Whether the Fault Is Bank-Specific
A V12 or W12 engine may store P0311 with other codes from the same cylinder bank.
Compare:
- Misfire counts across both banks
- Bank 1 and Bank 2 fuel trims
- Upstream oxygen or air-fuel sensor data
- Camshaft timing values
- Fuel-rail pressure where separate rails are used
- Intake manifold operation
- Bank-specific ignition and injector power supplies
If several cylinders on the same bank misfire, the underlying problem may involve:
- Bank-specific intake leak
- Camshaft timing error
- Fuel-rail pressure problem
- Oxygen sensor bias
- Shared wiring or ground
- Intake-runner control fault
- Exhaust restriction
P0311 alone points toward Cylinder 11. P0311 combined with several same-bank faults deserves a wider diagnostic view.
Step 4: Verify Cylinder 11 Location
Use vehicle-specific service information to identify Cylinder 11.
Inspect the surrounding area for:
- Disconnected coil or injector connectors
- Loose connector terminals
- Oil inside the spark plug well
- Coolant contamination
- Damaged wiring
- Rodent damage
- Cracked vacuum hoses
- Intake manifold leaks
- Wiring contacting hot components
- Loose engine grounds
Access may require removal of:
- Engine covers
- Intake ducts
- Air boxes
- Fuel rails
- Intake manifold components
- Cowl or bracing components
Confirm the correct procedure before beginning major disassembly.
Step 5: Inspect the Cylinder 11 Spark Plug
Remove the Cylinder 11 spark plug and compare it with a plug from a healthy cylinder.
Check for:
- Worn electrodes
- Excessive gap
- Cracked porcelain
- Carbon fouling
- Oil contamination
- Wet fuel deposits
- Coolant deposits
- Overheating
- Incorrect heat range
- Wrong plug type
- Improper torque
A fuel-wet plug may indicate that fuel is entering Cylinder 11 but the mixture is not igniting.
A dry plug may suggest inadequate fuel delivery.
Oil deposits may indicate:
- Worn piston rings
- Valve-guide problems
- PCV-system problems
- Leaking spark plug tube seal
- Oil entering the plug well
If the plugs are beyond their service interval, replace the complete set with the correct type and gap.
On a V12, replacing the full set may involve substantial labor. That still does not justify skipping diagnosis and replacing every ignition component within visual range.
Step 6: Swap the Cylinder 11 Ignition Coil
If the engine uses accessible coil-on-plug ignition, move the Cylinder 11 coil to another cylinder.
For example, swap the Cylinder 11 and Cylinder 9 coils. Clear the codes and operate the engine under conditions similar to those recorded in the freeze-frame data.
If the code changes from:
P0311 to P0309
the ignition coil is likely defective.
If P0311 returns on Cylinder 11, the coil probably is not the cause.
Inspect the coil and boot for:
- Carbon tracking
- Cracks
- Moisture
- Oil contamination
- Coolant contamination
- Corroded contacts
- Burned internal springs
- Damaged insulation
Review our bad ignition coil guide for additional ignition-system information.
Also see our ignition coil replacement guide before installing replacement components.
If moving the coil requires major disassembly, determine whether electrical testing offers a more practical first step.
Step 7: Understand P0311 Versus P0361
P0311 and P0361 describe related but different faults.
| Code | Meaning |
| P0311 | The PCM detected a combustion misfire associated with Cylinder 11 |
| P0361 | The PCM detected an electrical malfunction involving Ignition Coil K’s primary or secondary circuit |
P0361 provides stronger evidence of an ignition-coil circuit problem.
Possible P0361 causes include:
- Failed ignition coil
- Missing coil power
- Open trigger circuit
- Trigger circuit shorted to ground
- Trigger circuit shorted to voltage
- Loose connector terminal
- Corroded connector
- Damaged wiring
- Failed PCM coil driver
P0311 without P0361 may still be ignition-related, but fuel delivery, airflow, compression, and valve operation must also be tested.
Coil letters frequently correspond with cylinder numbers, but manufacturer information should be checked before assuming Coil K controls Cylinder 11.
Step 8: Test the Cylinder 11 Fuel Injector
A clogged, leaking, stuck, electrically open, or unpowered injector can cause P0311.
Listen to the Cylinder 11 injector with a mechanic’s stethoscope and compare it with the other injectors.
Further testing may include:
- Injector resistance measurement
- Injector voltage test
- Noid-light test
- Injector current-ramp test
- Injector balance test
- Fuel-pressure drop test
- Injector swap test where practical
Use manufacturer specifications for injector resistance and circuit testing.
Pro Street injector-testing resources include:
- How to Test a Ford Ranger Fuel Injector
- How to Test Nissan Altima Fuel Injectors
- How to Test a Toyota Corolla Fuel Injector
- How to Test an Acura RSX Fuel Injector
Never open a gasoline direct-injection fuel system without following the manufacturer’s pressure-relief procedure.
Step 9: Understand P0311 Versus P0211
P0211 identifies an electrical fault involving the Cylinder 11 injector circuit.
| Code | Meaning |
| P0311 | Cylinder 11 combustion misfire |
| P0211 | Cylinder 11 injector circuit malfunction |
If P0311 and P0211 appear together, concentrate on:
- Injector power supply
- Injector control circuit
- Connector condition
- Terminal tension
- Injector resistance
- Wiring performance under load
- PCM injector driver
P0211 does not automatically prove that the injector has failed. Damaged wiring or a loose connector can prevent a functional injector from operating.
Step 10: Inspect the Coil and Injector Circuits
If the ignition coil and injector test correctly, inspect their circuits.
Check for:
- Correct supply voltage
- Reliable ground
- Ignition-coil trigger signal
- Injector control pulse
- Loose terminal tension
- Corroded connector pins
- High circuit resistance
- Wiring shorted to ground
- Wiring shorted to voltage
- Heat-damaged insulation
- Poor engine or PCM grounds
Use voltage-drop testing while the circuit is operating whenever possible.
A circuit can show continuity and still fail under load. Electricity remains annoyingly unwilling to certify a wire merely because the multimeter beeped once.
PCM failure is possible but uncommon. Verify the component, wiring, voltage supply, grounds, and mechanical condition first.
Step 11: Check for an Intake Leak
An intake leak near the Cylinder 11 runner can create a localized lean condition.
Inspect:
- Intake manifold gasket
- Cylinder 11 injector seal
- Vacuum hoses
- PCV system
- Brake-booster hose
- Intake manifold
- Throttle-body gasket
- Intake-runner control hardware
A smoke test is generally the safest and most effective way to locate an intake-system leak.
Compare fuel trims between the two cylinder banks. A significantly more positive correction on Cylinder 11’s bank may support a bank-specific air or fuel-delivery problem.
Step 12: Check Bank-Specific Fuel Delivery
Some V12 and W12 engines use separate fuel rails, pressure sensors, pumps, or control circuits for different portions of the engine.
Review:
- Commanded and actual fuel-rail pressure
- Low-pressure fuel supply
- Bank-specific fuel trims
- Injector balance
- Pump duty cycle
- Fuel-pressure sensor data
- Fuel quality
A bank-specific fuel-pressure problem can make Cylinder 11 appear to be the primary fault while affecting several cylinders to a lesser degree.
Step 13: Perform a Compression Test
If Cylinder 11 has spark, fuel, and correct electrical control, test its compression.
Compare Cylinder 11 with the remaining cylinders and use manufacturer specifications for minimum pressure and allowable variation.
Low compression may be caused by:
- Burned intake valve
- Burned exhaust valve
- Bent valve
- Worn piston rings
- Damaged piston
- Broken valve spring
- Failed follower or lifter
- Worn camshaft lobe
- Head gasket failure
- Cylinder-wall damage
- Incorrect valve timing
If Cylinder 11 compression is low, continue with a cylinder leak-down test.
Step 14: Perform a Cylinder Leak-Down Test
Position Cylinder 11 at top dead center on its compression stroke and introduce regulated compressed air.
| Air heard or observed at | Likely fault |
| Throttle body or intake | Leaking intake valve |
| Exhaust outlet | Leaking exhaust valve |
| Oil filler opening | Piston rings or cylinder damage |
| Cooling system | Head gasket, cylinder head, or block damage |
| Adjacent cylinder | Head gasket failure between cylinders |
Leak-down testing helps determine whether P0311 originates from internal engine damage.
Step 15: Inspect Cylinder 11 Valve Operation
If compression is low or valvetrain noise is present, inspect valve movement.
Depending on the engine, testing may require:
- Removing the valve cover
- Comparing rocker-arm or follower movement
- Measuring valve lift
- Inspecting valve springs
- Checking lifters or followers
- Verifying engine oil pressure
- Inspecting the camshaft
- Checking the oil filter for metal debris
Reduced valve movement may indicate a failed follower, broken valve spring, collapsed lifter, or worn camshaft lobe.
Step 16: Check for Intake-Valve Deposits
Direct-injected engines can develop deposits on their intake valves because fuel no longer flows across the back of each valve.
Uneven deposits near Cylinder 11 may cause:
- Cold-start P0311
- Rough idle
- Airflow imbalance
- Misfire that improves after warm-up
A borescope inspection can help confirm deposits. Approved cleaning procedures may include media blasting or professional chemical cleaning.
Step 17: Clear P0311 and Verify the Repair
After repairing the confirmed fault:
- Clear stored and pending codes.
- Start the engine.
- Verify a stable idle.
- Monitor Cylinder 11 misfire counters.
- Recreate the original freeze-frame conditions when safe.
- Complete the required drive cycle.
- Scan for pending codes.
- Confirm that readiness monitors complete normally.
The repair is confirmed when Cylinder 11 misfire counts remain normal and P0311 does not return.
Common P0311 Repairs and Costs
Repair costs can be high on V12 and W12 engines because component access may require considerable disassembly.
| Repair | Approximate installed cost |
| Replace spark plugs | $300–$2,500 |
| Replace one ignition coil | $150–$1,200 |
| Replace coil boot | $100–$500 |
| Clean or replace one injector | $400–$3,000 |
| Repair wiring or connector | $200–$1,500 |
| Repair intake or vacuum leak | $300–$3,000 |
| Intake-valve carbon cleaning | $1,000–$5,000 |
| Replace intake manifold gasket | $1,500–$6,000 |
| Replace failed follower or camshaft | $3,000–$15,000+ |
| Cylinder-head or valve repair | $5,000–$20,000+ |
| Engine replacement | $15,000–$75,000+ |
These are broad estimates. Vehicle design, parts availability, labor rate, and component access can change the final cost considerably.
The failed component may cost less than the collection of brackets, hoses, wiring, and intake parts placed in front of it.
Common P0311 Diagnostic Mistakes
Replacing Coil 11 Without Testing It
Swap the coil with another cylinder when practical. If the fault follows, replace the coil. If P0311 remains, continue testing.
Testing the Wrong Cylinder
Cylinder numbering varies between V12 and W12 engines. Confirm Cylinder 11 before disassembly.
Confusing P0311 With P0361
P0311 identifies a combustion misfire. P0361 identifies an electrical fault involving Ignition Coil K’s circuit.
Ignoring P0211
P0311 combined with P0211 points toward the Cylinder 11 injector or its circuit and should change the diagnostic priority.
Ignoring Same-Bank Codes
Several codes on the same bank may indicate a shared intake, fuel-delivery, timing, wiring, or exhaust problem.
Replacing the Injector Without Testing It
Confirm injector power, control, resistance, and fuel delivery before replacement.
Clearing Freeze-Frame Data Too Early
Freeze-frame information may be the best evidence of the conditions that triggered P0311.
Skipping Compression Testing
If ignition and fuel tests pass, verify the mechanical condition of Cylinder 11.
Replacing the Catalytic Converter First
The catalytic converter may have been damaged by P0311. Repair the misfire before evaluating catalyst performance.
P0311 Frequently Asked Questions
Does P0311 Mean Ignition Coil 11 Is Bad?
No. A failed coil is common, but P0311 may also result from a spark plug, injector, wiring, intake leak, compression problem, or valvetrain failure.
Can P0361 Cause P0311?
Yes. P0361 identifies an electrical malfunction involving Ignition Coil K, which commonly corresponds with Cylinder 11. Verify the manufacturer’s coil assignment first.
Can P0211 Cause P0311?
Yes. A Cylinder 11 injector-circuit failure can prevent the cylinder from receiving the correct amount of fuel.
Can a Spark Plug Cause P0311?
Yes. A worn, cracked, fouled, overheated, or incorrectly gapped Cylinder 11 spark plug can trigger P0311.
Can a Fuel Injector Cause P0311?
Yes. A clogged, leaking, stuck, electrically failed, or unpowered Cylinder 11 injector can create a cylinder-specific misfire.
Can an Intake Leak Affect Only Cylinder 11?
Yes. An intake manifold or injector-seal leak near the Cylinder 11 runner may create a localized lean condition.
Can a Bank-Specific Fuel Problem Trigger P0311?
Yes. Separate fuel rails, pumps, pressure sensors, or control circuits may cause several cylinders on one bank to run incorrectly, with Cylinder 11 recording the highest misfire count.
Can Low Compression Cause P0311?
Yes. Burned valves, worn rings, piston damage, valvetrain faults, or head gasket failure can reduce Cylinder 11 compression.
Why Does P0311 Only Appear Under Acceleration?
A weak coil, worn plug, excessive plug gap, restricted injector, or fuel-pressure problem may only become noticeable as engine load increases.
Can I Drive With P0311?
Only briefly if the engine runs smoothly and the Check Engine Light remains steady. Stop driving if the light flashes, the engine shakes severely, power drops, or raw fuel can be smelled.
Can P0311 Damage the Catalytic Converter?
Yes. Unburned fuel can overheat and destroy the catalytic converter.
Will P0311 Clear Itself?
The Check Engine Light may turn off after several successful drive cycles, but stored or permanent code data may remain until the required self-tests are completed.
Related Misfire, Injector and Ignition Codes
- P0300 — Random or Multiple Cylinder Misfire
- P0307 — Cylinder 7 Misfire
- P0308 — Cylinder 8 Misfire
- P0309 — Cylinder 9 Misfire
- P0310 — Cylinder 10 Misfire
- P0311 — Cylinder 11 Misfire
- P0312 — Cylinder 12 Misfire
- P0211 — Cylinder 11 Injector Circuit Malfunction
- P0361 — Ignition Coil K Primary/Secondary Circuit Malfunction
Explore the Pro Street OBD-II Code Libraries
Use the Pro Street cornerstone pages to find additional diagnostic trouble codes:
- All P OBD-II Codes Explained — Powertrain Codes
- All B OBD-II Codes Explained — Body and SRS Codes
- All C OBD-II Codes Explained — Chassis Codes
- OBD-II DTC Doctor
P0311 identifies a combustion misfire associated with Cylinder 11. Save the freeze-frame information and verify the correct cylinder before removing components.
Inspect the spark plug, swap-test the ignition coil where practical, and test the injector and related circuits. If P0311 remains, inspect for intake leaks, bank-specific fuel problems, low compression, and abnormal valve operation.
The correct repair is the one supported by testing—not the component with the most impressive packaging.