P0306: Fix Cylinder 6 Misfire in 2014-2020 RAM 1500 ICARZONE UR800
P0306: Fix Cylinder 6 Misfire in 2014-2020 RAM 1500
Diagnose and repair P0306 (Cylinder 6 Misfire Detected) in your 5.7L HEMI RAM 1500 with ICARZONE UR800—avoid dealer markup.
Fix RAM 1500 P0306 with UR800Table of Contents
1. What is P0306 in RAM 1500 5.7L HEMI?
P0306 is an OBD-II diagnostic trouble code indicating “Cylinder 6 Misfire Detected”. For the 2014-2020 RAM 1500 equipped with the 5.7L HEMI V8 engine, this code means the Engine Control Module (ECM) has detected incomplete combustion in the 6th cylinder—one of the rear cylinders on the driver’s side of the engine (firing order: 1-8-4-3-6-5-7-2).
The 5.7L HEMI relies on a coil-on-plug ignition system (each cylinder has its own ignition coil) and sequential fuel injection to deliver 395 HP and 410 lb-ft of torque—critical for towing (up to 10,620 lbs) and hauling. A misfire in cylinder 6 disrupts this balance: unburned fuel enters the exhaust (damaging catalytic converters) and reduces power, especially under load.
RAM 1500 Specific: The 2014-2020 5.7L HEMI uses Chrysler’s Variable Valve Timing (VVT) system. Cylinder 6’s ignition coil (Mopar #56029405AA) is positioned near the exhaust manifold, making it more prone to heat-related failure than front cylinders—explaining why P0306 is 2x more common than other cylinder-specific misfire codes in RAM 1500s.
2. Top Causes of P0306 in 2014-2020 RAM 1500 5.7L HEMI
Based on RAM service bulletins and owner forums (RAM1500Forum.com), these are the most common causes of P0306 in the 5.7L HEMI—ranked by frequency in real-world cases:
| Cause | Frequency in RAM 1500 | Why It Triggers P0306 | Typical Mileage When It Occurs |
|---|---|---|---|
| Failing Ignition Coil (Cylinder 6) | 45% | Heat from exhaust manifold degrades coil windings; Mopar #56029405AA fails to deliver consistent spark. | 55,000-75,000 miles |
| Worn Spark Plug (Cylinder 6) | 25% | OEM iridium plugs (Champion #RE14MCC4) wear prematurely in cylinder 6 due to heat; gap expands to >0.050”. | 60,000-80,000 miles |
| Fuel Injector Failure (Cylinder 6) | 15% | Direct-injection injector (Mopar #04891573AB) clogs or leaks; disrupts fuel spray pattern in cylinder 6. | 70,000-90,000 miles |
| Intake Manifold Runner Control (IMRC) Stuck | 10% | IMRC valve for cylinder 6 sticks closed; restricts airflow, causing lean condition and misfire. | 45,000-65,000 miles |
| Valve Spring Failure | 5% | Weak exhaust valve spring in cylinder 6 (common in 2014-2016 models); prevents proper valve closure. | 80,000-100,000 miles |
Real RAM Owner Case: A 2017 RAM 1500 Laramie 5.7L HEMI with 68,000 miles developed P0306 when towing a 7,000-lb trailer. Using ICARZONE UR800’s Cylinder Balance Test, the owner confirmed cylinder 6 was contributing 0% power at idle. Replacing the ignition coil (Mopar #56029405AA) and spark plug (Champion #RE14MCC4) resolved the misfire—costing $85 DIY vs. $420 at a RAM dealer.
3. Key Symptoms of P0306 in RAM 1500 5.7L HEMI
P0306 symptoms in the RAM 1500 5.7L HEMI are most noticeable under load (towing, accelerating uphill) due to the engine’s demand for maximum power. Here’s how to identify the issue:
Performance Symptoms
- Loss of power: Struggles to accelerate uphill or maintain speed with a trailer.
- Reduced towing capacity: Can’t pull maximum rated load without bogging down.
- Poor fuel economy: Drop from 16-17 MPG (highway) to 12-14 MPG.
- Hesitation: Stumbles when pressing the accelerator from a stop.
Mechanical & Audible Symptoms
- Rough idle: Vibration felt in the steering wheel and cab (worse when engine is warm).
- Check Engine Light (CEL): Illuminates solid; may flash under heavy load (severe misfire).
- Exhaust odor: Strong smell of unburned fuel (from cylinder 6’s uncombusted fuel).
- Knocking noise: Detonation in cylinder 6 (lean condition from injector issues).
Critical Warning: If your RAM’s CEL is flashing with P0306, stop towing immediately. A flashing CEL indicates unburned fuel is damaging the catalytic converter—replacing it costs $1,200-$1,800 for the 5.7L HEMI’s dual-exhaust system.
4. Diagnose P0306 in RAM 1500 5.7L HEMI with ICARZONE UR800
RAM dealers charge $150-$200 to diagnose P0306, but the ICARZONE UR800 lets you pinpoint the cause in 15 minutes. Unlike generic scanners, it accesses the RAM 1500’s HEMI-specific data and runs Chrysler-approved tests.
Step-by-Step Diagnosis with UR800
| Step | UR800 Function | What to Do (RAM 1500 Specific) | How to Interpret Results |
|---|---|---|---|
| 1 | Full System Scan | Connect UR800 to RAM’s OBD-II port (under dashboard, driver’s side). Select “Chrysler” > “RAM” > “1500” > “2014-2020” > “5.7L HEMI.” | Confirm P0306; check for related codes (P0356 = coil 6 fault, P0206 = injector 6 fault). |
| 2 | Live Data Stream | Select “HEMI Engine Data” > Monitor critical parameters for cylinder 6:
|
Normal: All values within range. Abnormal: Dwell time <1.0 ms (bad coil); Pulse width >3.0 ms (clogged injector). |
| 3 | Cylinder Balance Test | Select “Active Tests” > “Cylinder Contribution Test.” UR800 disables each cylinder sequentially. | Pass: RPM drops 50-75 RPM when other cylinders are disabled. Fail: No RPM drop when cylinder 6 is disabled (confirms misfire). |
| 4 | Injector Leak Test | Select “RAM Specific Tests” > “Fuel Injector Leakdown.” UR800 pressurizes the fuel system and monitors pressure. | Pass: Pressure drops <5 PSI in 5 minutes. Fail: Pressure drops >10 PSI (leaking injector in cylinder 6). |
| 5 | RAM TSB Lookup | Enter RAM’s VIN > Select “Technical Service Bulletins.” | Check for TSB 21-003 (2014-2016 RAM 1500): Addresses P0306 from faulty valve springs in cylinder 6. |
5. Step-by-Step P0306 Repairs for RAM 1500 5.7L HEMI
Once UR800 identifies the cause, these RAM-specific repairs will resolve P0306. Always use Mopar OEM parts for the 5.7L HEMI—aftermarket parts often fail prematurely:
Repair 1: Replace Ignition Coil & Spark Plug (Most Common Fix)
- Ensure engine is cool (allow 3+ hours after running).
- Disconnect the negative battery terminal (10mm wrench) – prevents electrical shock.
- Locate cylinder 6: On the 5.7L HEMI, it’s the driver’s side rear cylinder (furthest from the front of the truck).
- Remove the plastic engine cover (4 Torx T25 screws).
- Disconnect the ignition coil’s electrical connector (press tab and pull straight back).
- Remove the 10mm bolt securing the coil to the cylinder head.
- Gently pull the coil straight up to remove (use a coil puller if stuck).
- Use a 5/8” spark plug socket with extension to remove the old spark plug.
- Inspect the spark plug: Look for oil fouling (sign of valve cover gasket leak) or excessive wear (gap >0.050”).
- Install new Mopar ignition coil (#56029405AA) and Champion spark plug (#RE14MCC4):
- Gap spark plug to 0.040” (critical for HEMI engines).
- Torque spark plug to 18 ft-lbs (do not over-tighten).
- Torque coil bolt to 8 ft-lbs.
- Reconnect the coil’s electrical connector and battery terminal.
- Use UR800 to clear codes and run “Ignition System Relearn” (5-minute process).
Repair 2: Replace Fuel Injector (Cylinder 6)
- Relieve fuel pressure: Remove the fuel pump fuse (located in the underhood fuse box) and start the engine until it stalls.
- Disconnect the negative battery terminal.
- Remove the intake manifold cover (Torx T30 screws).
- Locate the fuel rail: Runs across the top of the engine; cylinder 6’s injector is on the driver’s side rear.
- Disconnect the injector’s electrical connector (press tab and pull).
- Remove the 10mm bolts securing the fuel rail to the cylinder head.
- Gently lift the fuel rail to access the injector (wiggle slightly to break O-ring seal).
- Remove the old injector and replace O-rings with Mopar injector seal kit (#5149065AA).
- Install new Mopar fuel injector (#04891573AB) – ensure O-rings are lubricated with clean engine oil.
- Reinstall fuel rail (torque bolts to 10 ft-lbs) and reconnect all components.
- Reinstall fuel pump fuse and battery terminal.
- Use UR800 to run “Fuel Injector Calibration” and clear codes.
Repair 3: Fix Intake Manifold Runner Control (IMRC)
- Disconnect battery terminal and remove intake manifold cover.
- Locate the IMRC module: Mounted on the driver’s side of the intake manifold.
- Disconnect the IMRC’s electrical connector and vacuum lines.
- Remove the 8mm bolts securing the IMRC to the manifold.
- Inspect the IMRC valve for cylinder 6: Ensure it moves freely (stuck valves need replacement).
- Replace IMRC module with Mopar #53034343AB (complete assembly).
- Reinstall all components and torque bolts to 8 ft-lbs.
- Use UR800 to run “IMRC Adaptation” and verify operation.
6. P0306 Repair Costs: DIY vs. RAM Dealer (1500 5.7L HEMI)
Repair costs for P0306 in the RAM 1500 5.7L HEMI vary based on the cause, but DIY repairs offer significant savings over RAM dealer service:
| Repair Type | DIY Cost (Parts + Tools) | RAM Dealer Cost (Parts + Labor) | DIY Time Required |
|---|---|---|---|
| Ignition Coil + Spark Plug (Cylinder 6) | $75-$100 (Mopar coil: $50; Champion plug: $15) | $350-$450 (labor: $120/hour x 2.5 hours) | 1-1.5 hours |
| Fuel Injector (Cylinder 6) | $120-$160 (Mopar injector: $100; seal kit: $20) | $500-$650 (labor: $120/hour x 3.5 hours) | 2-2.5 hours |
| IMRC Module Replacement | $200-$250 (Mopar module: $180) | $700-$850 (labor: $120/hour x 4 hours) | 2.5-3 hours |
| Valve Spring Replacement (Cylinder 6) | $80-$120 (spring kit: $60; valve seals: $20) | $1,200-$1,500 (labor: $120/hour x 8 hours) | 4-5 hours (advanced DIY) |
| Diagnosis Only | $0 (with ICARZONE UR800) | $150-$200 | 15 minutes |
Cost Savings Tip: The ICARZONE UR800 pays for itself in one repair. Replacing the ignition coil and spark plug DIY saves $275-$375 vs. dealer service—more than covering the UR800’s cost.
7. Prevent P0507 in Your RAM 1500 5.7L HEMI
The 5.7L HEMI is a durable engine, but proactive maintenance will help you avoid P0306 and extend its lifespan—critical for RAM 1500 owners who use their trucks for towing:
- Replace Ignition Coils Proactively: Swap all 8 coils at 70,000 miles (not just cylinder 6). Use Mopar #56029405AA—aftermarket coils fail 2x faster in the HEMI’s high-heat environment.
- Change Spark Plugs Every 60,000 Miles: Use Champion #RE14MCC4 iridium plugs (OEM spec). Gap to 0.040” – incorrect gap causes coil stress and misfires.
- Use High-Quality Fuel: Fill up with 89-octane gasoline (minimum). The HEMI’s high compression (10.5:1) requires mid-grade fuel to prevent detonation and injector clogging.
- Clean Fuel Injectors Annually: Use Mopar Fuel System Cleaner (#4318060AB) every 10,000 miles. For towing trucks, do a professional cleaning at 50,000 miles.
- Inspect Valve Cover Gaskets: Check for oil leaks every 30,000 miles. Leaking gaskets (Mopar #53021870AB) coat coils in oil, causing premature failure in cylinder 6.
- Run UR800 Health Checks: Use the UR800’s “HEMI Engine Health Scan” every 15,000 miles to catch weak coils or injectors before they trigger P0306.
- Avoid Short Trips: The HEMI needs to reach operating temperature (200°F) to burn off carbon buildup. If you use your RAM for short trips, take it on a 20-minute highway drive weekly.
8. RAM 1500 5.7L HEMI P0306 FAQs
Can I drive my RAM 1500 with P0306?
Short distances (under 20 miles) are okay if symptoms are mild, but avoid towing or heavy loads. Prolonged driving with P0306 damages the catalytic converter and reduces fuel economy.
Should I replace all 8 ignition coils if only cylinder 6 fails?
Yes—RAM 1500 coils age uniformly. If cylinder 6’s coil fails at 65,000 miles, others will fail soon. Replacing all 8 (Mopar #56029405AA) prevents repeated P030x codes and saves time.
Why is cylinder 6 more prone to misfires in the HEMI?
Cylinder 6 is a rear cylinder on the driver’s side, positioned closest to the exhaust manifold. It runs 20-30°F hotter than front cylinders, accelerating coil and plug wear.
Will P0306 fail my RAM’s emissions test?
Yes. Unburned fuel from cylinder 6 increases hydrocarbon emissions, which will cause a failed test. Most states also fail vehicles with active trouble codes like P0306.
Does RAM’s warranty cover P0306 repairs?
New RAM 1500s have a 3-year/36,000-mile basic warranty and 5-year/60,000-mile powertrain warranty. If P0306 is from a defective coil or injector, it’s covered. TSB 21-003 covers valve springs up to 100,000 miles.
Can the ICARZONE UR800 fix P0306 without parts?
No—UR800 diagnoses the cause (bad coil, clogged injector), but you’ll need to replace faulty parts. However, it saves you from buying unnecessary parts (e.g., replacing all injectors when only cylinder 6 is bad).
Fix P0306 in Your RAM 1500 5.7L HEMI Today
The ICARZONE UR800 is the only scanner built for RAM 1500 owners. It diagnoses P0306 in 15 minutes, includes HEMI-specific tests, and saves you $300+ on dealer diagnostics and repairs.
Buy ICARZONE UR800 NowSummary: P0306 in RAM 1500 5.7L HEMI
P0306 (Cylinder 6 Misfire) is a common issue in 2014-2020 RAM 1500 5.7L HEMI models, primarily caused by failing ignition coils (45% of cases), worn spark plugs (25%), or fuel injector issues (15%). Symptoms include power loss, rough idle, and reduced towing capacity—worse under load.
The ICARZONE UR800 simplifies diagnosis with RAM-specific tools: live data monitoring, cylinder balance tests, and TSB lookup. Most cases are fixed by replacing the cylinder 6 coil and plug ($75-$100 DIY) or injector ($120-$160 DIY)—saving $275-$500 vs. dealer service.
Prevent P0306 by replacing coils every 70,000 miles, using 89-octane fuel, and running UR800 health checks. With the UR800, you can keep your RAM 1500’s HEMI engine running strong for towing and hauling.
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