P0306 on 2011-2014 Chrysler 300: Cylinder 6 Misfire Causes and Fixes

What's Unique About the 2011-2014 Chrysler 300

For the 2011-2014 Chrysler 300, the story of P0306 is really a tale of two engines. While any engine can have a simple coil or plug failure, the early 3.6L Pentastar V6 (2011-2013 models) is known for a specific manufacturing defect in the left cylinder head that causes misfires on cylinders 2, 4, and 6. Chrysler acknowledged this issue with a technical service bulletin (09-002-14) and a generous warranty extension (X56), making it a critical first check for V6 owners. For the robust 5.7L HEMI V8, P0306 is often a standard ignition fault but can also be an early sign of the infamous 'Hemi tick' caused by a failing lifter on cylinder 6.

Diagnostic Flowchart

Tap your situation to follow the diagnostic path that matches what you're seeing on this vehicle.

Symptoms You May Notice

• Rough or shaking idle
• Noticeable loss of engine power and sluggish acceleration.
• Check Engine Light is on and may be flashing, especially under load.
• Engine hesitation or stumbling.
• Increased fuel consumption
• A ticking or tapping sound from the engine, particularly on the 3.6L V6 (can indicate rocker arm or cylinder head issues) or 5.7L V8 (can indicate lifter failure).
• Jerking or bucking during acceleration.

Most Likely Causes

1. Defective Left Cylinder Head (3.6L V6 Only) 🔴 High Probability → Shop Engine Cylinder Head Early (2011-2013) 3.6L Pentastar engines had a manufacturing defect causing excessive wear on the valve guides and seats of the left-bank cylinder head, which includes cylinder 6. This was addressed by TSB 09-002-14 and a warranty extension (X56). 🎬 Watch: How to get this cylinder head repair for free. The issue applies to engines built on or before July 25, 2012.
   How to confirm: A professional mechanic should perform a cylinder leak-down test on cylinder 6. Per TSB 09-002-14, leakage of 25% or more confirms the failure and necessitates head replacement. Owners often report hearing a distinct ticking noise accompanying the misfire codes.
   Typical fix: Replacement of the left cylinder head with the updated part (part number ending in AC or later).
   Est. part cost: $700-$1200
2. Faulty Ignition Coil 🔴 High Probability → Shop Ignition Coil
   How to confirm: Swap the ignition coil from cylinder 6 with another cylinder (e.g., cylinder 4 on the V6, or cylinder 4 on the V8). Clear the codes and drive the car. If the code changes to P0304, the ignition coil is the culprit. This is the most common first diagnostic step recommended on owner forums.
   Typical fix: Replace the failed ignition coil.
   Est. part cost: $30-$70
3. Worn or Fouled Spark Plug 🟡 Medium Probability → Shop Spark Plug
   How to confirm: Remove the spark plug from cylinder 6 and inspect it. Look for heavy carbon buildup, oil fouling, a worn electrode, or a cracked insulator. Compare it to a new plug. Even if it looks okay, it can be faulty.
   Typical fix: Replace the spark plug on cylinder 6. It is best practice to replace all spark plugs at the same time if they are near the end of their service life.
   Est. part cost: $10-$25 per plug
4. Failed Lifter / Worn Camshaft (5.7L V8) 🟡 Medium Probability → Shop Engine Camshaft The 5.7L HEMI engine, particularly those with the Multi-Displacement System (MDS), is known for lifter failures. The roller on the lifter can seize, causing it to grind against the camshaft lobe, leading to a loss of valve lift and a misfire. This often starts as a light ticking noise that is more noticeable at idle when the engine is warm.
   How to confirm: Diagnosis is difficult without disassembly. After ruling out ignition and fuel issues, a mechanic may need to pull the valve cover and cylinder head to inspect the lifters and camshaft lobes for wear and damage. A misfire that gets worse under heavy acceleration can be a strong indicator.
   Typical fix: Replacement of the camshaft and all lifters. This is a major engine repair. Some owners opt to install an 'MDS delete kit' at this time.
   Est. part cost: $600-$1500 for a cam and lifter kit.
5. Faulty Fuel Injector ⚪ Low Probability → Shop Fuel Injector
   How to confirm: This is more complex. A mechanic can perform a fuel injector balance test or use a diagnostic tool to command the injector on and off while listening for a click with a stethoscope. Some DIYers swap the injector with another cylinder, similar to the coil swap test, but this is more labor-intensive.
   Typical fix: Replace the fuel injector for cylinder 6.
   Est. part cost: $50-$120

Rare But Worth Checking

• Failed Rocker Arm (3.6L V6): → Shop Engine Rocker Arm Separate from the cylinder head defect, the 3.6L Pentastar is also known for rocker arm failure, where the roller bearing disintegrates. This creates a loud ticking noise and can eventually damage the camshaft lobe 🎬 Watch: Identifying and fixing the common Pentastar engine tick., causing a persistent misfire. One owner on a forum confirmed a P0306 was ultimately solved by replacing a worn exhaust rocker arm and cam lobe on cylinder 6.
• Intake Manifold Gasket Leak: → Shop Engine Intake Manifold A vacuum leak near the intake port for cylinder 6 can lean out the air/fuel mixture, causing a misfire. This can sometimes be found by carefully spraying brake cleaner near the gasket with the engine running and listening for a change in idle speed.
• Low Engine Compression: Separate from the V6 cylinder head issue, low compression from worn piston rings or a burnt valve can cause a misfire. A compression test will diagnose this.

Diagnosis Steps

1. Read the codes with an OBD-II scanner to confirm P0306 and check for any other codes.
2. Determine your engine (3.6L V6 or 5.7L V8). This is critical for diagnosis.
3. Listen to the Engine: Note any ticking or tapping sounds. A tick from the top driver's side of the 3.6L V6 points towards valvetrain issues. A light, ping-pong-like ticking from the 5.7L V8 at warm idle suggests a lifter problem.
4. Locate Cylinder 6: On the 3.6L V6, it's on the driver's side (Bank 2), closest to the radiator. On the 5.7L V8, it's on the passenger's side (Bank 2), the middle cylinder.
🎬 See this simple walkthrough for diagnosing Hemi engine misfires.
5. Swap the Ignition Coil: Swap the coil from cylinder 6 with an easily accessible cylinder. Clear the codes and see if the misfire code moves to the new cylinder. If it does, the coil is bad. This is the most common and easiest first step.
6. Inspect/Swap the Spark Plug: If the misfire remains on cylinder 6, move the spark plug from cylinder 6 to another cylinder. If the misfire follows the plug, the plug is bad.
7. Inspect Wiring: Check the connector and wiring going to the ignition coil and fuel injector on cylinder 6 for any damage or corrosion.
8. (3.6L V6 Specific): If steps 5-7 do not solve the issue, strongly consider the known cylinder head defect (2011-2013 models) or a failed rocker arm. Contact a dealer or qualified shop to discuss TSB 09-002-14 and have a cylinder leak-down test performed.
9. (5.7L V8 Specific): If ignition parts are good, the next likely culprit is a failed lifter/camshaft. This is a complex repair that should be confirmed by a professional, often requiring removal of the valve cover and head for inspection.

Parts You'll Likely Need

• Ignition Coil (OEM #5149168AH) — A very common failure item that directly causes a misfire on a single cylinder.
  Trusted brands: Mopar, NGK, Delphi
  OEM price range: $50-$80
  Aftermarket price range: $30-$60
• Spark Plug (OEM #SP149125AE) — Spark plugs are a routine maintenance item. A worn, fouled, or cracked plug will not fire correctly, causing a misfire.
  Trusted brands: Mopar, NGK, Champion
  OEM price range: $15-$25
  Aftermarket price range: $8-$15
• Left Cylinder Head Assembly (3.6L V6) (OEM #68141353AC) — This is the updated part number to fix the known manufacturing defect on 2011-2013 3.6L engines that causes P0306. It supersedes previous part numbers like RL141353AC, 68141353AB, and 68141353AA.
  Trusted brands: Mopar
  OEM price range: $700-$1200
  Aftermarket price range: Not Recommended

Related Codes That Often Appear With This One

• P0300 — If the cylinder head issue on the 3.6L V6 is severe, or if there are multiple failing coils or a significant fuel delivery problem, the PCM may log P0300 (Random/Multiple Cylinder Misfire) in addition to the specific cylinder code.
• P0302, P0304 — On the 3.6L V6, these codes often appear with P0306 as they are all on the same problematic left cylinder head.

Technical Service Bulletins (TSBs) & Recalls

• 09-002-14 Rev B: Describes the diagnosis (cylinder leakage test of 25% or more) and repair (left cylinder head replacement) for P0300, P0302, P0304, or P0306 on 3.6L engines built before July 25, 2012, due to the cylinder head issue.
• 1809416 / 18-094-16: Lists P0306 as 'Cylinder 6 Misfire' among a series of other potential diagnostic trouble codes.

Platform-Specific Known Issues

• A significant number of 2011-2013 Chrysler 300 models with the 3.6L V6 engine were prone to premature failure of the left cylinder head. This would cause misfire codes P0302, P0304, and/or P0306. Chrysler issued warranty extension X56 (related to TSB 09-002-14), extending coverage for the left cylinder head to 10 years or 150,000 miles.
• For the 5.7L HEMI V8, a P0306 code accompanied by a ticking sound is often the result of a failed MDS (Multi-Displacement System) lifter. The lifter's roller bearing fails, destroying the camshaft lobe and causing a misfire that is often more pronounced under load.

Mechanic-Grade Diagnostic Values

• Ignition Coil Primary Resistance — expected: 0.49 - 0.57 Ω. Failure: A reading outside this range indicates a faulty coil winding.
• Ignition Coil Secondary Resistance — expected: 9.5 - 11.1 kΩ. Failure: A reading outside this range indicates a faulty secondary coil winding.
• Fuel Pressure (Both Engines) — expected: 58 ± 5 psi. Failure: Significantly lower pressure indicates a weak fuel pump or clogged filter; higher pressure can indicate a faulty regulator.
• 3.6L V6 Engine Oil Pressure (Warm Idle) — expected: ~30 psi. Failure: Consistently low pressure at idle can indicate oil pump wear or other internal engine issues, affecting VVT and lifter function.
• 3.6L V6 Engine Oil Pressure (Warm, Under Load) — expected: 60 - 70 psi. Failure: Failure to build pressure with RPM can point to a faulty variable displacement oil pump or other lubrication system problems.

Hidden / Shadow Codes Worth Checking

• Mode $06 Misfire Data: Provides raw misfire counts for each individual cylinder, including those that have not yet reached the threshold to set a specific P030x code. This is critical for identifying intermittent misfires or confirming the fault is isolated to cylinder 6. (see via Using a professional scan tool like the dealer wiTECH, navigate to PCM/ECM > Monitors > OBD II Monitors > 'Which cylinder is misfiring'.)

Scan Tool Commands That Help

• wiTECH: View 'Which cylinder is misfiring' Monitor — Use this to get live, real-time data on misfire events per cylinder. It helps confirm that cylinder 6 is the primary or only offender, especially when a random misfire code P0300 is also present.
• wiTECH: Loss of Communication Test — In rare cases where a misfire code is accompanied by other communication codes or erratic electronic behavior, this test can be used to check the stability of the CAN bus network between modules like the PCM and TIPM.

Wiring & Ground Locations

• G901a — Located at the left front of the engine compartment.. This is a primary engine ground. On the 3.6L V6, cylinder 6 is on the left bank (driver's side). A poor connection at this ground could cause electrical issues for the ignition coil and fuel injector on that bank, leading to a misfire.
• G101 — Located at the right front of the engine compartment.. This is another primary engine ground. On the 5.7L V8, cylinder 6 is on the right bank (passenger's side). A corroded or loose connection here could affect the ignition and fuel circuits for that cylinder.

Real Owner Repair Stories

• Reddit user zparts in r/Justrolledintotheshop (Dodge 5.7L Hemi (in a vehicle with 310,000 miles)) — Came into the shop with a P0306 misfire code.
  ❌ Tried (didn't work) Not specified, but the diagnosis went beyond simple ignition parts.
  ✅ What actually fixed it The root cause was found to be a damaged MDS lifter and a worn camshaft lobe for cylinder 6, requiring replacement of the camshaft and lifters.

OEM Part Supersession History

• 5038785AA, 53021726AD → 5038785AB, 5038785AC, 05038785AD, 68060714AA — Revisions to the 5.7L HEMI MDS lifters to improve durability and address failure modes.
  Heads up: It is critical to replace lifters as a set and ensure the correct MDS vs non-MDS lifters are used in the correct cylinder locations.
• N/A → R8259594AB — This is the Mopar remanufactured part number for the complete 3.6L long block engine assembly for 2011-2013 models, which would include the updated cylinder head design.

Model Year Variations Within This Range

• 2012-2014: Beginning with the 2012 model year, Chrysler 300 models with the 3.6L V6 engine were equipped with the more advanced and efficient 8-speed 845RE automatic transmission, replacing the previous 5-speed automatic from 2011.
• 2011-2013: 3.6L V6 engines built on or before July 25, 2012, are prone to the left cylinder head defect. Engines built after this date, and used in 2013-2014 models, should have the revised cylinder head from the factory, making the issue far less likely.