P0305 on 2014-2021 Dodge Challenger: Cylinder 5 Misfire Causes and Fixes

What's Unique About the 2014-2021 Dodge CHALLENGER

The 2014-2021 Dodge Challenger was available with several engines, including the 3.6L Pentastar V6 and various HEMI V8s (5.7L, 6.4L, 6.2L). While the cause of a P0305 misfire is often a simple ignition component, HEMI engines are notorious for potential camshaft and lifter issues. This failure, often called the 'Hemi tick,' occurs when the needle bearings in a lifter's roller fail, causing the roller to seize and grind down the camshaft lobe. This prevents the valve from opening fully, causing a persistent misfire that won't be fixed by new plugs or coils. The 3.6L Pentastar V6 has its own known weakness with rocker arm bearings failing, which can also score the camshaft and lead to misfires.

Diagnostic Flowchart

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

Generation note: The 2014-2021 model years are all part of the third generation of the Dodge Challenger. However, the platform received a significant refresh in 2015 with updated styling and powertrain revisions, including the introduction of the 485-hp 6.4L V8 and the supercharged Hellcat engine. The fundamental causes of a P0305 code, from ignition components to the infamous 'Hemi tick', remain consistent across these years and engine types.

Symptoms You May Notice

• Rough or shaky idle.
• Hesitation or stumbling during acceleration.
• Noticeable loss of engine power.
• Flashing or solid Check Engine Light.
• Fuel smell from the exhaust.
• Audible ticking or tapping noise from the engine bay, especially on HEMI V8s.

Most Likely Causes

1. Faulty Ignition Coil 🔴 High Probability Coil-on-plug systems are common failure points on modern engines due to constant exposure to heat and vibration. This is the most frequent cause of a single-cylinder misfire.
   How to confirm: Swap the ignition coil from cylinder 5 with an adjacent, easily accessible cylinder (e.g., cylinder 3 on a V8). Clear the codes and drive the vehicle. If the code changes to P0303, the coil is faulty. This is the definitive, no-cost first diagnostic step.
   Typical fix: Replace the faulty ignition coil. It's a simple unbolt-and-unplug process requiring only basic tools.
   Est. part cost: $30 - $100
2. Worn or Fouled Spark Plug 🔴 High Probability Spark plugs are a regular maintenance item. HEMI engines use two spark plugs per cylinder, doubling the chance of a single plug failing. Incorrect gapping or oil fouling from other issues can cause a weak or non-existent spark.
   How to confirm: After ruling out the coil, remove the spark plug(s) from cylinder 5. Inspect for wear (worn electrode), carbon buildup, oil, or damage to the ceramic insulator. Compare the plug's condition to one from a healthy cylinder.
   Typical fix: Replace the spark plug(s). It is highly recommended to replace all spark plugs at the same time for consistent performance and to reset the maintenance interval.
   Est. part cost: $5 - $25 per plug
3. Defective Fuel Injector 🟡 Medium Probability Injectors can become clogged with fuel deposits over time or fail electrically. This is a known, though less common, issue on both Pentastar V6 and HEMI engines.
   How to confirm: Listen to the injector with a mechanic's stethoscope; it should have a consistent clicking sound. You can also check the injector's resistance with a multimeter (expect 12-14.5 ohms on a 3.6L) or swap it with another cylinder's injector, though this is more labor-intensive as it requires removing the fuel rail.
   Typical fix: Replace the faulty fuel injector. This often requires removing the fuel rail.
   Est. part cost: $50 - $150
4. Vacuum Leak ⚪ Low Probability Intake manifold gaskets can degrade over time, causing unmetered air to enter a specific cylinder, leading to a lean condition and misfire.
   How to confirm: With the engine running, spray brake cleaner or a propane torch (unlit) around the intake manifold gasket near cylinder 5. If the engine RPM changes, a leak is present. A P0171 (System Too Lean) code may also be present, as seen in one owner's experience.
   Typical fix: Replace the intake manifold gaskets.
   Est. part cost: $20 - $60

Rare But Worth Checking

• Camshaft/Lifter Failure (The 'Hemi Tick'): This is a significant and well-documented issue, particularly on the 5.7L HEMI, but possible on all HEMI variants. The needle bearings inside a valve lifter fail, causing the lifter's roller to seize. The seized roller then grinds against the spinning camshaft lobe, wearing it down. This reduces valve lift, causing insufficient airflow and a persistent misfire (like P0305) that is not resolved by replacing ignition or fuel parts. Diagnosis involves removing the valve cover to observe valve movement; a failed lifter will result in visibly less travel on the rocker arm for that cylinder. Repair is extensive and involves replacing the camshaft, all lifters, and related gaskets.
• Rocker Arm Failure (3.6L Pentastar): On the 3.6L V6 engine, a similar valvetrain failure is common. The needle bearings in the rocker arms can fail, scoring the camshaft and causing a ticking noise along with a misfire code like P0305. This was common enough that Chrysler issued TSBs linking misfire codes to this issue and has been the subject of class-action lawsuits. Diagnosis and repair are similar to the HEMI lifter failure, requiring valve cover removal for inspection.
• Low Engine Compression: Caused by mechanical issues like a worn piston ring, a bad valve, a dropped valve seat (seen in some early HEMIs), or a blown head gasket. A compression test and a cylinder leak-down test are required to diagnose this mechanical failure after all other causes are ruled out.

Diagnosis Steps

1. Confirm the P0305 code is present using an OBD-II scanner. Note if any other codes like P0300 or P0205 are also stored.
2. Listen for a 'Hemi tick'. A distinct, rhythmic ticking noise from the driver's side of the engine is a strong clue for a potential lifter/camshaft issue on V8s.
3. Identify the location of cylinder 5. On the 3.6L V6, it is the middle cylinder on the driver's side. On V8s (5.7L, 6.4L, 6.2L), it is the third cylinder back on the driver's side.
4. Perform an ignition coil swap. Move the coil from cylinder 5 to another cylinder (e.g., cylinder 1 or 3). Clear codes and drive. If the code changes to P0301 or P0303, replace the bad coil.
5. If the code remains P0305, inspect the spark plugs for cylinder 5. Replace them if they are worn, fouled, or damaged. It's best practice to replace all 8 (or 16 on HEMIs).
🎬 Watch this walkthrough for replacing all 16 spark plugs on a Hemi.
6. If the issue persists, inspect the wiring and connector for the ignition coil and fuel injector on cylinder 5 for damage, looseness, or corrosion.
7. Test the fuel injector. Listen with a stethoscope for a steady clicking sound. If it's quiet or sounds different from other injectors, it may be faulty. Consider swapping the injector with another cylinder if you have the mechanical ability.
8. If a ticking noise is present and the above steps did not resolve the issue, the next step is to inspect for mechanical failure. This involves removing the driver's side valve cover and observing the rocker arm movement for cylinder 5 while the engine is cranked. Reduced movement indicates a collapsed lifter and worn camshaft lobe.
9. If no ticking is present and all else fails, perform a compression test on cylinder 5 to check for internal mechanical problems like bad rings or valves.

Parts You'll Likely Need

• Ignition Coil (OEM #68238603AA (Fits most 5.7L, 6.4L, 6.2L HEMI engines)) — This is the most common failure part for a single-cylinder misfire. It's responsible for generating the high voltage for the spark plug.
  Trusted brands: Mopar, NGK, Denso
  OEM price range: $75 - $100
  Aftermarket price range: $30 - $75
• Spark Plug (OEM #SP149212AC (Common for 6.4L HEMI)) — As a routine maintenance item, spark plugs wear out over time, leading to a weak or inconsistent spark. HEMI engines have two plugs per cylinder, increasing the chances of failure.

Related Codes That Often Appear With This One

• P0300 — If the misfire is intermittent, severe enough to affect crankshaft timing broadly, or if other cylinders are also beginning to fail (e.g., multiple bad lifters), a P0300 (Random/Multiple Cylinder Misfire) may be stored alongside P0305.
• P0205 — This code indicates a malfunction in the cylinder 5 injector circuit. If you see P0205 with P0305, the fuel injector or its wiring/connector is almost certainly the culprit.

Technical Service Bulletins (TSBs) & Recalls

• 1400322REVA: Lists P0305 - Cylinder 5 Misfire as a potential cause for a rough idle.
• 18-094-16: Lists P0305 - Cylinder 5 Misfire among other misfire and engine sensor codes.
• 09-011-25 (Referenced for Pentastar V6): Acknowledges the link between engine misfire codes and valvetrain noise, relevant for diagnosing rocker arm failure on the 3.6L engine.

Platform-Specific Known Issues

• The provided NHTSA Technical Service Bulletins confirm that P0305 is a recognized fault code across various Dodge models, often associated with a rough idle. [Bulletin #1400322REVA, Bulletin #18-094-16]
• On HEMI engines, a P0305 accompanied by a ticking sound is a classic symptom of a failed lifter roller, which then destroys the camshaft lobe for cylinder 5. This is a widely documented pattern failure.
• On 3.6L Pentastar V6 engines, a persistent P0305 with a ticking noise often points to a failed rocker arm needle bearing, a known weakness for that engine family.

Mechanic-Grade Diagnostic Values

• 3.6L V6 Fuel Injector Resistance — expected: Approximately 12.0 to 14.5 ohms.. Failure: A reading significantly outside this range, especially a very low reading (under 1 ohm) or an open circuit, indicates a failed injector.
• 5.7L V8 HEMI Ignition Coil Primary Resistance — expected: 0.558 to 0.682 ohms at room temperature.. Failure: A reading outside of this specific range indicates a faulty coil winding.
• Mode $06 Misfire Counts — expected: Zero or very low counts on all cylinders during a drive cycle.. Failure: An advanced scan tool can access Mode $06 data, which shows raw misfire counts for each cylinder. A high or rapidly increasing count on cylinder 5, even before the P0305 code is set, confirms it is the problem cylinder.

Scan Tool Commands That Help

• wiTECH or advanced aftermarket scanner: Injector Kill / Cylinder Balance Test — This bidirectional command allows a technician to disable the fuel injector for a specific cylinder (e.g., cylinder 5). If the engine's idle quality does not change when cylinder 5's injector is disabled, it confirms that the injector was not contributing to the engine's operation, pointing to a fuel, spark, or compression issue in that cylinder.

Wiring & Ground Locations

• G102 / G103 — Typically located at the rear of the engine or on the cowl/firewall in the engine compartment. For example, on some models, G102 grounds the ignition coils and is at the left rear of the engine, while G103 is on the cowl above the brake booster.. The ignition coils and PCM require a solid ground connection to function. A loose or corroded ground at these locations can cause intermittent and hard-to-diagnose electrical issues, including misfires. Verifying these grounds are clean and tight is a crucial step when electrical causes are suspected.
• Cylinder 5 Ignition Coil Connector — Directly on top of the ignition coil for cylinder 5 (third cylinder from the front on the driver's side for V8s).. The primary wires in this connector supply power and the trigger signal from the PCM. A technician can back-probe this connector to check for battery voltage (with key on) and a pulsing ground signal from the PCM while cranking, confirming the PCM is commanding the coil to fire.

Real Owner Repair Stories

• YouTube video from 'House of Teks' (2011 Chrysler 300C 5.7L Hemi (similar engine and failure mode)) — Cylinder 5 misfire (P0305).
  ❌ Tried (didn't work) Replacing spark plugs, Replacing ignition coil
  ✅ What actually fixed it The actual cause was a completely worn-down lobe on the camshaft for cylinder 5, caused by a failed lifter. The repair required replacing the camshafts.
• Reddit user on r/Challenger (2021 Scat Pack (6.4L V8)) — P0305 code appeared the same day the car was purchased from a dealership.
  ❌ Tried (didn't work) The dealership initially claimed to have fixed it by addressing a 'plug wire'.
  ✅ What actually fixed it The user did not report the final mechanical fix but resolved the issue by escalating the complaint to FCA corporate and the Better Business Bureau (BBB) after the dealership provided poor service for a brand new car failing immediately. This highlights that for new vehicles, leveraging warranty and consumer protection channels is a critical step.

OEM Part Supersession History

• 56029129AA, 56029129AB, 56029129AF, 68060346AA → 68238603AA — Standard part evolution for improved reliability or manufacturing changes.
  Heads up: The parts are generally interchangeable for the specified HEMI engines (5.7L, 6.4L, etc.), but it is always best to use the latest revision (68238603AA) when replacing.

Model Year Variations Within This Range

• 2016+: For the 3.6L Pentastar V6, an updated version was introduced starting in the 2016 model year. This second-generation Pentastar featured changes like a two-step variable valve lift (VVL) system and improved fuel injectors. While the rocker arm failure issue can still occur, the design was modified.
• 2015+: The 2015 model year marked a significant refresh for the Challenger, including new powertrain options like the 6.4L '392' Scat Pack and the supercharged 6.2L Hellcat. The ignition coil part number 68238603AA is often specified for vehicles built after April 2015.