P0303 on 2012-2016 Dodge Caravan: Cylinder 3 Misfire Causes and Fixes

What's Unique About the 2012-2016 Dodge CARAVAN

The 2012-2016 Dodge Caravan exclusively uses the 3.6L Pentastar V6 engine. On this engine, cylinder 3 is located on the rear cylinder bank (Bank 1, passenger side, middle cylinder), which is pressed against the firewall. This location makes diagnosis and repair more labor-intensive than for the front cylinders, as the upper intake manifold must be removed to access the spark plug and ignition coil. While early Pentastar engines (2011-2013) were known for a left cylinder head issue (affecting cylinders 2, 4, 6) covered by an extended warranty, P0303 points to the right bank. For a right-bank misfire like P0303, a mechanical valvetrain issue is more likely to be a failing rocker arm, a separate known weakness of this engine family.

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 shaky idle
• Hesitation or stumbling during acceleration
• Noticeable loss of engine power
• Flashing or solid Check Engine Light
• Decreased fuel economy
• Fuel smell from the exhaust
• Audible ticking noise from the top of the engine, often associated with rocker arm failure

Most Likely Causes

1. Faulty Ignition Coil 🔴 High Probability → Shop Ignition Coil Ignition coils are a common failure item on many modern engines as they age. The rear bank location may subject them to higher ambient temperatures, potentially shortening their lifespan.
   How to confirm: The most effective method is to swap the cylinder 3 ignition coil with another cylinder's coil (e.g., cylinder 2 on the easily accessible front bank). Clear the codes and run the engine. If the code changes to P0302, the coil is confirmed to be bad.
   Typical fix: Replace the faulty ignition coil. 🎬 Watch this guide on replacing rear bank coil packs. It is often recommended to replace all three coils and spark plugs on the rear bank at the same time due to the labor involved in removing the intake manifold.
   Est. part cost: $25-$75 per coil
2. Worn or Fouled Spark Plug 🔴 High Probability → Shop Spark Plug The original equipment iridium spark plugs have a long service interval (around 100,000 miles), but can fail earlier or cause misfires when the gap wears too wide. An oil or coolant leak can also foul the plug, causing a misfire.
   How to confirm: After swapping the coil without success, swap the spark plug from cylinder 3 with another cylinder. If the misfire code follows the plug, the plug is the issue. Visually inspect the removed plug for wear, oil fouling, or damage to the ceramic insulator.
   Typical fix: Replace the spark plug. It is best practice to replace all six spark plugs at the same time, especially if they are near their service life.
   Est. part cost: $10-$25 per plug
3. Faulty Fuel Injector 🟡 Medium Probability → Shop Fuel Injector
   How to confirm: Listen to the injector with a mechanic's stethoscope; it should have a consistent clicking sound. A more definitive test is to check the injector's resistance with a multimeter; a bad injector may show an open circuit or abnormal resistance. A diagnostic scan tool can also show an open circuit for the injector, as seen in a 2015 Grand Caravan repair video. 🎬 See how to replace fuel injectors on the 3.6L engine.
   Typical fix: Replace the faulty fuel injector. This also requires removing the intake manifold and fuel rail. It's recommended to replace the O-rings on all injectors that are removed.
   Est. part cost: $50-$120 per injector
4. Rocker Arm / Lifter Failure 🟡 Medium Probability → Shop Engine Rocker Arm The 3.6L Pentastar engine is known for rocker arm bearing failures, which causes a distinct ticking sound often called the 'Pentastar Tick'. The needle bearings in the rocker's roller can fail, causing the arm to seize or drag, which in turn wears down the camshaft lobe. This prevents the valve from opening fully, leading to a loss of compression and a persistent misfire.
   How to confirm: This is an advanced diagnosis. A distinct ticking noise from the top of the engine is a strong indicator. A compression test on cylinder 3 may show lower-than-normal readings. Definitive diagnosis requires removing the valve cover to visually inspect for worn camshaft lobes and failed rocker arm bearings.
   Typical fix: Requires replacing all rocker arms and lifters on the affected cylinder bank (Bank 1). If the camshaft is damaged from the failed rocker, it will also need replacement. This is a labor-intensive job.
   Est. part cost: $200-$500 for parts

Rare But Worth Checking

• Low Compression / Cylinder Head Issue: → Shop Engine Cylinder Head While the famous Pentastar head issue primarily affected the left bank (cylinders 2, 4, 6) on 2011-2013 models, head-related problems like bad valve seats or a failed head gasket can occur on any cylinder and cause a persistent misfire. A compression test is the first step to diagnosing this. One owner of a 2014 Caravan with P0303 had the issue resolved by replacing the cylinder head due to a burnt exhaust valve.
• Intake Manifold Gasket Leak: → Shop Engine Intake Manifold A vacuum leak from a failed upper or lower intake manifold gasket can lean out the air-fuel mixture on one or more cylinders, causing a misfire. A smoke test is the best way to confirm a leak. A Reddit user with a 2014 Caravan was advised to check for vacuum leaks around the injector seal after replacing all other components.
• Faulty Powertrain Control Module (PCM): → Shop Engine Control Module (ECM) TSB 18-069-16 was issued for some 2015-2016 models built between July 27, 2015 and September 11, 2015. An improperly sealed vent on the PCM could allow for moisture intrusion, causing a range of misfire codes, including P0303. The prescribed fix is to replace the PCM.

Diagnosis Steps

1. Read the code with an OBD-II scanner and confirm P0303 is present. Note any other codes, especially P0300, P219A, or P0203.
2. Identify Cylinder 3: It is the middle cylinder on the rear bank (Bank 1), located against the firewall.
3. Perform an ignition coil swap. Since cylinder 3 is hard to access, swap it with cylinder 2 (front of the engine, driver's side). This requires removing the upper intake manifold.
4. Clear the codes, start the engine, and let it run until the check engine light returns.
5. Re-scan for codes. If the code is now P0302, the ignition coil is faulty and needs replacement.
6. If the code remains P0303, the coil is likely good. Swap the spark plug between cylinder 3 and cylinder 2.
7. Clear codes and re-run the test. If the code moves to P0302, the spark plug is faulty.
8. If the code remains P0303, investigate the fuel injector. Listen for a steady clicking sound. Test the injector's resistance with a multimeter or check for an open circuit with a scan tool.
9. If a distinct ticking noise is heard from the engine, suspect a mechanical issue. Perform a cylinder compression test on cylinder 3 to check for problems like a failed rocker arm.
10. If compression is good, check for vacuum leaks using a smoke machine, paying close attention to the upper and lower intake manifold gaskets and the injector seals.
11. PRO-TIP for DIY: When reinstalling the intake manifold, the upper manifold bolts should be torqued to approximately 89 in-lbs (7.4 ft-lbs) and the lower manifold bolts to 8.8 ft-lbs. Always use new gaskets.

Parts You'll Likely Need

• Ignition Coil (OEM #5149168AH) — This is one of the most common failure points for a single-cylinder misfire. The part number 5149168AH is a common OEM number for this application.
  Trusted brands: Mopar, NGK, Denso, Bosch
  OEM price range: $50-$90
  Aftermarket price range: $25-$60
• Spark Plug (OEM #SP149125AE) — Spark plugs are a routine maintenance item and a primary cause of misfires as they wear out or become fouled. The OEM plugs are typically Iridium for long life.
  Trusted brands: NGK, Champion, Denso
  OEM price range: $15-$25 per plug
  Aftermarket price range: $8-$20 per plug

Related Codes That Often Appear With This One

• P0300 — If the misfire is intermittent or affects other cylinders, a P0300 (Random/Multiple Cylinder Misfire) may be stored alongside P0303.
• P219A — This code indicates a Bank 1 Air-Fuel Ratio Imbalance. A misfire on cylinder 3 (which is in Bank 1) can cause this imbalance, as seen in a diagnostic video on a 2015 Grand Caravan where a bad injector caused both codes.
• P0301, P0305 — These codes indicate misfires on other cylinders in the same bank (Bank 1). If they appear together, it may point to a systemic issue like a clogged catalytic converter, bad fuel pump, or a significant vacuum leak affecting the entire bank.
• P0203 — This code indicates a malfunction in the cylinder 3 injector circuit. If P0203 is present with P0303, the fuel injector or its wiring harness is almost certainly the culprit.

Technical Service Bulletins (TSBs) & Recalls

• Bulletin #18-069-16: Mentions P0303 as a potential Diagnostic Trouble Code (DTC) that can be set in the PCM.
• Bulletin #18-104-15: Also lists P0303 as a possible DTC related to engine performance issues.

Platform-Specific Known Issues

• Rocker Arm Failure ('Pentastar Tick'): → Shop Engine Rocker Arm A widely documented weakness of the 3.6L Pentastar engine family is the failure of needle bearings inside the rocker arms. This causes the arm's roller to stop spinning, leading to friction that wears down the camshaft lobe. The result is a distinct ticking noise and a loss of valve lift, which causes a compression-based misfire code like P0303.
• Faulty PCM (TSB 18-069-16): For a specific build range of 2015-2016 models (July-Sept 2015), Chrysler issued a Technical Service Bulletin for misfire codes caused by a faulty PCM. An improperly coated vent could allow moisture damage, leading to various misfire codes. The only solution is a complete PCM replacement.

Mechanic-Grade Diagnostic Values

• Fuel Injector Resistance — expected: 12.0 - 12.5 Ohms. Failure: An open circuit (infinite resistance) or a significantly different reading. One real-world example showed a failed injector with an open circuit. Another source suggests a range of 12-16 Ohms.
• Ignition Coil Primary Resistance — expected: ~0.53 Ohms (based on MSD aftermarket coil specs). Failure: A reading significantly higher or lower than the specification for the specific coil being tested.
• Fuel Pressure (at fuel rail) — expected: 58 psi +/- 2 psi (400 kPa +/- 14 kPa). Failure: Pressure significantly below 56 psi, which would typically cause multiple misfires (P0300) rather than a single cylinder misfire.
• Camshaft Position Sensor Ground Circuit Resistance — expected: Less than 3.0 Ohms. Failure: Resistance higher than 3.0 Ohms indicates a poor ground, which can cause erratic signals and potentially misfire-related codes.
• Camshaft Position Sensor Voltage (Key On, Engine Off) — expected: 5-volt reference signal. Failure: No voltage or significantly lower voltage indicates a wiring or PCM issue.

Scan Tool Commands That Help

• wiTECH (or equivalent professional scanner): View 'Which cylinder is misfiring' monitor — When diagnosing a general P0300 random misfire code, this function in the OBD II monitors section allows a technician to see live misfire counts for each individual cylinder to isolate the problematic one(s).
• wiTECH (or equivalent professional scanner): Fuel Memory Reset — After replacing a fuel injector, this function resets the long-term fuel trim adaptive memory. This forces the PCM to immediately start learning with the new component, preventing the engine from running on old, incorrect fuel trim values.
• wiTECH: PCM Reprogramming (Flash) — This is the required repair procedure for TSB 18-069-16, which addresses misfire codes caused by a faulty PCM on specific 2015-2016 models. It involves replacing the PCM and then flashing it with the latest software.

Real Owner Repair Stories

• YouTube channel 'Kurt's Auto' (2015 Dodge Grand Caravan 3.6L with 120,000 miles) — Rough running, Check Engine Light on with codes P0303 (Cylinder 3 Misfire) and P219A (Bank 1 Air-Fuel Ratio Imbalance).
  ❌ Tried (didn't work) Swapped ignition coil from cylinder 3 to cylinder 1; the misfire code remained P0303., Inspected the spark plug from cylinder 3; it showed no signs of damage or unusual wear.
  ✅ What actually fixed it The fuel injector for cylinder 3 was tested with a multimeter and found to have an open circuit (infinite resistance). Replacing the faulty fuel injector and all injector O-rings resolved both the P0303 and P219A codes.
• ALLDATA Tech-Assist Case Study (2011 Dodge Grand Caravan 3.6L with 68,882 miles) — Malfunction Indicator Light on, slight engine misfire.
  ❌ Tried (didn't work) Tested the ignition coil and spark plug for cylinder 3; both were good., Checked the injector trigger signal with an oscilloscope; the signal was normal.
  ✅ What actually fixed it A compression pressure pattern test using an oscilloscope showed uneven intake and exhaust valve pressures. A visual inspection after removing the valve cover revealed worn-out camshaft lobes. Replacing the camshaft fixed the P0303 misfire.
• ScannerDanner Forum User (2014 Dodge Grand Caravan 3.6L SXT) — Initial code was P0303 due to a burnt exhaust valve. After replacing the cylinder head, a new misfire code P0305 appeared.
  ❌ Tried (didn't work) Swapped coils, spark plugs, and injectors for cylinder 5 with no change., A leakdown test on cylinder 5 passed.
  ✅ What actually fixed it The user reported the initial P0303 was caused by a burnt exhaust valve requiring a cylinder head replacement. The subsequent P0305 on the new head was not resolved in the thread, but the initial cause of P0303 is a valuable data point for mechanical failure.

OEM Part Supersession History

• 5149168AH, 5149168AI → 5149168AJ — Standard part revision by the manufacturer, likely for improved reliability and resistance to heat-induced failure.
  Heads up: The newest part number, 5149168AJ, is the correct and most current replacement for all previous versions on pre-2016 engines.
• 5184296AG (and earlier revisions) → 5184296AH — Updated design for the engine valve rocker arms to address premature failure of the internal needle bearings, which causes the 'Pentastar Tick'.
  Heads up: While older versions may physically fit, using the latest 'AH' revision is highly recommended for durability when replacing rocker arms on any 2011+ 3.6L engine.

Model Year Variations Within This Range

• 2016: For the 2016 model year, the 3.6L Pentastar V6 was significantly upgraded (sometimes referred to as the Pentastar Upgrade or PUG). Changes included a two-stage variable valve lift (VVL) system, a higher compression ratio, and new designs for fuel injectors and ignition coils. This means some ignition and fuel components may not be interchangeable with 2012-2015 models.
• 2015-2016 (specific build dates): Vehicles built between July 27, 2015, and September 11, 2015, are subject to TSB 18-069-16, which identifies a potentially faulty PCM as the cause for various misfire codes, including P0303.