P0302 on 2014-2018 Ram ProMaster 1500: Cylinder 2 Misfire Causes and Fixes

What's Unique About the 2014-2018 Ram ProMaster 1500

The 3.6L Pentastar V6 is a widely used engine across the Chrysler, Dodge, Jeep, and Ram lineups. While common misfire causes like plugs and coils are prevalent, this engine family has a known history of valvetrain issues. A persistent P0302 that isn't resolved by ignition parts often points towards these more serious mechanical problems. The two most notorious issues are: 1) A defective left cylinder head on earlier (pre-2014) models that caused misfires on cylinders 2, 4, and 6, leading to TSB 09-002-14 and an extended warranty (X56). 2) Failure of the rocker arm roller bearings, which seize and destroy the camshaft lobe, causing a characteristic 'Pentastar Tick' and a persistent misfire.

Symptoms You May Notice

• Flashing or solid Check Engine Light
• Rough or shaking idle
• Engine hesitation or stumbling during acceleration
• Reduced engine power
• Difficulty starting the engine
• Decreased fuel economy
• Audible ticking or tapping noise from the top of the engine, especially the driver's side

Most Likely Causes

1. Failed Ignition Coil 🔴 High Probability Coil-on-plug systems are a common failure point on most modern engines due to heat and vibration.
   How to confirm: Swap the ignition coil from cylinder #2 with another cylinder (e.g., cylinder #4, the middle cylinder on the same bank). Clear the codes and drive the vehicle. If the code changes to P0304, the coil is the faulty part.
   Typical fix: Replace the failed ignition coil. Many owners choose to replace the corresponding spark plug at the same time. Accessing the front bank on a ProMaster is relatively easy.
   Est. part cost: $30-$75
2. Worn or Fouled Spark Plug 🔴 High Probability
   How to confirm: After ruling out the ignition coil, remove the spark plug from cylinder #2. Inspect it for wear (worn electrode), carbon fouling, oil, or damage. Compare it to a new plug to assess its condition.
   Typical fix: Replace the spark plug. It is recommended to replace all six spark plugs at the same time for even performance, though this requires removing the intake manifold for the rear bank.
   Est. part cost: $10-$25 per plug
3. Failed Rocker Arm / Lifter 🟡 Medium Probability The 3.6L Pentastar engine is notorious for failure of the rocker arm's needle bearings, which can seize, stop rotating, and grind down the corresponding camshaft lobe, causing a loss of valve lift and a misfire. This is often preceded by an audible ticking sound.
   How to confirm: This typically requires professional diagnosis. A ticking or tapping noise from the driver's side top of the engine that increases with RPM is a strong indicator. Diagnosis requires removing the valve cover to visually inspect the camshaft lobes for scoring and the rocker arms for play or seizure. A compression test may also show low compression on cylinder #2.
   Typical fix: Replace all failed rocker arms and lifters on the affected bank, and the camshaft if it is damaged. This is a complex and labor-intensive repair. 🎬 Watch: Complete guided repair for rocker arm replacement
   Est. part cost: $500-$1500+
4. Faulty Fuel Injector ⚪ Low Probability
   How to confirm: Listen to the injector with a mechanic's stethoscope; it should have a consistent clicking sound. Compare it to an adjacent injector. You can also swap the injector with another cylinder to see if the misfire follows, but this is a more involved job requiring removal of the fuel rail.
   Typical fix: Replace the faulty fuel injector. It's often recommended to replace all injectors on the same fuel rail at the same time.
   Est. part cost: $50-$150
5. Cracked Left Cylinder Head ⚪ Low Probability This was a well-documented factory defect on 2011-2013 Pentastar engines, but some early 2014 models could still be affected. The issue was excessive wear of the valve guides on the left cylinder head (Bank 2), causing a loss of compression and misfires on cylinders 2, 4, and 6.
   How to confirm: This is diagnosed via a cylinder leak-down test. Per TSB 09-002-14, leakage of 25% or more confirms the failure. This is a professional-level diagnosis.
   Typical fix: Replace the left cylinder head with the updated part. This was covered under an extended warranty (X56: 10 years/150,000 miles), but that has likely expired for all vehicles.
   Est. part cost: $800-$1500 for the head assembly

Rare But Worth Checking

• Low Engine Compression: If ignition and fuel components are good, a compression test is the next step. Low compression on cylinder #2 could indicate a bad valve, worn piston rings, or a head gasket leak, all of which are serious internal engine problems.
• Vacuum Leak: A leak in the intake manifold gasket near the runner for cylinder #2 can lean out the air-fuel mixture and cause a misfire. This would often be accompanied by other lean codes or a P0300.

Diagnosis Steps

1. Read the trouble codes with an OBD-II scanner. 🎬 Watch: A guide to diagnosing Pentastar misfire codes Confirm that P0302 is the primary code. Listen for any ticking noises from the engine.
2. To test the ignition coil, swap the coil from cylinder #2 (front, driver's side) with the coil from cylinder #4 (middle, driver's side).
3. Clear the codes and drive the vehicle until the check engine light returns.
4. If the code is now P0304, the ignition coil is bad and needs to be replaced.
5. If the code remains P0302, the coil is likely good. Proceed to inspect the spark plug.
6. Remove the spark plug from cylinder #2. Check for excessive wear, damage, or fouling (black, wet, or white deposits). Replace if necessary. It's good practice to replace all plugs on the front bank while you're there.
7. If the plug and coil are good, inspect the wiring and connector for the cylinder #2 ignition coil and fuel injector for damage or corrosion.
8. If a ticking noise is present or the simple fixes did not work, a mechanical issue is likely. A professional diagnosis is recommended.
9. Perform an engine compression test on all cylinders, paying close attention to cylinder #2. A significant drop compared to other cylinders indicates an internal problem.
10. If compression is low, perform a cylinder leak-down test. Per Chrysler TSB 09-002-14, leakage over 25% on cylinder 2 would condemn the cylinder head.
11. If compression is good but a tick is present, remove the valve cover to inspect the camshaft and rocker arms for cylinder #2 for visible wear or damage.

Parts You'll Likely Need

• Ignition Coil (OEM #5149168AI, 5149168AJ) — This is one of the most common failure points for a single-cylinder misfire and is easy to replace on the front bank.
  Trusted brands: Mopar, NGK, Denso, Delphi
  OEM price range: $50-$80
  Aftermarket price range: $30-$60
• Spark Plug (OEM #SP149125AE) — Spark plugs are a routine maintenance item and a frequent cause of misfires as they wear out.
  Trusted brands: Champion, NGK
  OEM price range: $15-$25
  Aftermarket price range: $10-$20
• Fuel Injector (OEM #0280158233, 5184085AC) — A clogged or electrically failed injector will prevent fuel from reaching the cylinder, causing a misfire.
  Trusted brands: Mopar, Bosch
  OEM price range: $100-$150
  Aftermarket price range: $50-$100
• Rocker Arm (OEM #5184296AH) — A well-known failure point on the 3.6L Pentastar engine that leads to ticking noises and misfires.
  Trusted brands: Mopar, Melling
  OEM price range: $15-$25 per arm
  Aftermarket price range: $10-$20 per arm
• Hydraulic Lifter / Tappet (OEM #5184332AA) — Often replaced along with the rocker arms during valvetrain service to ensure proper function.
  Trusted brands: Mopar, Melling
  OEM price range: $10-$20 per lifter
  Aftermarket price range: $8-$15 per lifter

Related Codes That Often Appear With This One

• P0300 — If the misfire is intermittent or affects multiple cylinders, a P0300 (Random/Multiple Cylinder Misfire) code may be stored alongside P0302. This is common with the cylinder head or rocker arm issues.
• P0304, P0306 — If P0302 is present with P0304 and/or P0306, it strongly points to a systemic issue on the left cylinder bank (Bank 2), such as the known cylinder head defect.

Technical Service Bulletins (TSBs) & Recalls

• 09-002-14 REV. B: This bulletin specifically addresses misfires on the left cylinder bank (which includes cylinder #2) for 2011-2013 models. It instructs technicians to perform a cylinder leak-down test and, if leakage exceeds 25%, to replace the left cylinder head under the X56 extended warranty. While the ProMaster is a 2014+ model, this TSB establishes the historical precedent for this failure mode on the Pentastar engine.
• D-14-12 (X56): This is the dealer communication that officially announced the extended warranty for the left cylinder head on certain 2011-2013 vehicles with the 3.6L engine to 10 years or 150,000 miles. It directly references Service Bulletin 09-002-14 for the repair procedure.

Platform-Specific Known Issues

• Easy Access to Front Bank (Bank 2): Unlike many other vehicles with the 3.6L Pentastar, the transverse mounting in the ProMaster places Bank 2 (cylinders 2, 4, 6) at the front of the engine bay, making access to the ignition coils, spark plugs, and even the valve cover for that bank relatively straightforward for diagnosis and repair.
• Rocker Arm Failure causing Camshaft Damage: A common owner experience is to first notice a ticking sound, which is then followed by the P0302 code. In many documented cases, mechanics find that the rocker arm for cylinder #2 has seized and worn a groove into the intake camshaft lobe, requiring replacement of the cam, rocker, and lifter to fix.

Mechanic-Grade Diagnostic Values

• Fuel Injector Resistance — expected: 12.0 - 12.5 Ohms. Failure: A significantly higher reading (e.g., over 16 Ohms), or an open/infinite reading, indicates a failed injector.
• Ignition Coil Primary Winding Resistance — expected: 0.4 - 2.0 Ohms. Failure: A reading outside this range indicates a faulty coil winding.
• Ignition Coil Secondary Winding Resistance — expected: 8.5 - 10.5 kΩ (kilo-ohms). Failure: A reading significantly outside this range points to a failure in the coil's secondary circuit.
• Cylinder Leak-Down Test — expected: Less than 25% leakage. Failure: Leakage of 25% or greater indicates a significant mechanical issue, such as bad valves, piston rings, or the known cylinder head defect.
• Ignition Coil Connector Voltage (Pin 1, ASD Relay Output) — expected: Battery Voltage (~12V) with Key On, Engine Off. Failure: No voltage suggests a problem with the ASD (Auto Shutdown) relay, its fuse, or the wiring harness, not the coil itself.

Hidden / Shadow Codes Worth Checking

• Live Misfire Counters: Instead of a specific code, the dealer-level scan tool can display a live counter of misfire events for each individual cylinder. This allows a technician to see which cylinder is misfiring in real-time, even if the misfires are not yet severe enough to set a permanent P0302 code. (see via This data is accessible using the Chrysler/Ram wiTECH or wiTECH 2.0 diagnostic software, often under the OEM data stream or specific misfire monitor screens.)

Scan Tool Commands That Help

• wiTECH: Clear Mis-fire TLC (Tooth Learn Correction) — After performing repairs related to the crankshaft position or valvetrain, this function is used to clear the learned crankshaft tooth profile, forcing the PCM to relearn it. This can resolve misfire detection inaccuracies.
• wiTECH: Mis-fire Mon SWC Screen — This diagnostic screen is used during a specific drive cycle to verify that the misfire monitor is actively running ('In Progress'). It helps confirm the PCM is able to test for misfires after a repair or software update.
• Professional Scan Tool (e.g., TOPDON, Autel): Relative Compression Test — This non-invasive test uses crankshaft speed variations during cranking to quickly identify a cylinder with lower compression than the others, pointing towards a mechanical issue without needing a manual compression gauge initially.

Wiring & Ground Locations

• Primary Engine/Transmission Ground Strap — A braided ground strap connecting the transmission case to a bolt on the driver's side transmission mount, which is secured to the vehicle's frame. It is often visible by looking down past the driver's side headlight assembly.. A corroded or loose main ground strap can cause erratic behavior in all engine electronics, including inconsistent spark from the ignition coils and faulty sensor readings, leading to misfire codes that are difficult to trace. It can also cause slow cranking or no-start symptoms.
• Cylinder 2 Ignition Coil Connector — The electrical connector on the ignition coil for the front-most cylinder on the driver's side.. Pin 2 is the PCM driver circuit, which provides the pulsing ground to fire the coil. A damaged wire or pin at this location will prevent the coil from firing, directly causing a P0302. Testing for a pulsing ground signal here can confirm the PCM and wiring are functioning correctly.

Real Owner Repair Stories

• YouTube user comment (Not specified, but had a P0302) — Cylinder 2 misfire code.
  ❌ Tried (didn't work) Replacing ignition coils, Replacing spark plugs
  ✅ What actually fixed it The owner used a bottle of Redline fuel injection cleaner in the fuel tank, which successfully cleared a clogged fuel injector and resolved the misfire code.
• BobIsTheOilGuy forum user (2015 Grand Caravan (3.6L Pentastar)) — P0300 (Random Misfire), shaky engine, hard to start, strong smell of gas after a repair.
  ❌ Tried (didn't work) Disassembling and re-checking engine timing.
  ✅ What actually fixed it The owner had installed aftermarket rocker arms which had the wrong profile (more lift), preventing the valves from closing fully. Replacing them with correct OEM Mopar rocker arms (P/N 5184296AH) resolved all issues.
• YouTube video by 'Jeep Life' (2015 Jeep Wrangler (3.6L Pentastar)) — P0303 (Cylinder 3 Misfire)
  ❌ Tried (didn't work) Swapping ignition coils, Swapping spark plugs
  ✅ What actually fixed it The owner tested the fuel injector resistance with a multimeter and found the failing cylinder's injector read 63.2 Ohms, far out of the ~12 Ohm specification. This confirmed the injector was electrically faulty and needed replacement.

"I Checked Everything" — The Actual Cause

• A common scenario for a persistent P0302 on the 3.6L Pentastar involves a technician performing standard diagnostics with no conclusive results. Ignition coils and spark plugs are swapped or replaced, fuel pressure is confirmed to be good, and a smoke test reveals no vacuum leaks. The misfire remains on cylinder #2. The actual cause is often a mechanical failure of a rocker arm roller bearing, which cannot be detected by these tests. The diagnosis requires removing the valve cover to physically inspect the camshaft lobes and rocker arms for scoring and seizure, a step often missed in initial diagnosis.

OEM Part Supersession History

• 5184296AD, AE, AF, AG → 5184296AH — The original rocker arms used needle bearings that were prone to premature failure, leading to the 'Pentastar tick' and camshaft damage. The updated 'AH' part features a more durable design to prevent this common failure.
  Heads up: It is critical to use the latest 'AH' revision for any valvetrain repair to prevent a repeat failure.
• 5184085AC (Bosch 0280158233) → 5184085AD — Likely minor updates to manufacturing or internal components by the supplier.
  Heads up: The PCM is sensitive to precise flow rates; using cheap or incorrect aftermarket injectors has been reported to cause other running issues. Sticking to OEM or a direct Bosch replacement is recommended.
• 68223569AC → 68223569AD — Likely minor manufacturing changes or a shift in suppliers for the ignition coil.

Model Year Variations Within This Range

• 2014-2018: While the 3.6L Pentastar engine received an upgrade (PUG) in some Chrysler platforms around 2016, the ProMaster continued to use the original 3.6L engine paired with the 62TE 6-speed automatic transmission through the 2021 model year. Therefore, the causes and fixes for P0302 are generally consistent across the 2014-2018 range.

Diagnostic Flowchart

Real Owner Stories

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

Related OBD-II Codes

• P0300 — Random/Multiple Cylinder Misfire Detected. Often appears alongside P0302 if the misfire condition affects multiple cylinders, and is explicitly grouped with P0302 in Chrysler TSB 09-002-14 regarding left cylinder head failures.
• P0304 — Cylinder 4 Misfire Detected. Cylinder 4 shares the left cylinder head (Bank 2) with cylinder 2. This code is also used during diagnosis: if swapping the coil from cylinder 2 to 4 causes the code to change to P0304, the coil is confirmed faulty.
• P0306 — Cylinder 6 Misfire Detected. Like P0304, cylinder 6 is on the same bank as cylinder 2. Misfires on cylinders 2, 4, and 6 together strongly point to the left cylinder head valve guide wear issue described in TSB 09-002-14.
• P0352 — Ignition Coil 'B' Primary/Secondary Circuit. This code indicates an electrical issue with the ignition coil circuit for cylinder 2, which would directly cause a P0302 misfire.

Frequently Asked Questions