P0302 on RAM: How to Diagnose & Fix
Cylinder 2 Misfire Detected
4 RAM models · 8 documented issues · 6 critical · $200-$12,000 repair
P0302 on RAM by model: symptoms, diagnosis and fix
The RAM 3500 6.7L Cummins equipped with the integrated exhaust brake system experiences failures of the VGT (Variable Geometry Turbocharger) actuator and exhaust brake solenoid. The exhaust brake uses the VGT turbo vanes to create backpressure for engine braking while towing. The electronic actuator (Holset HE351VE/HE300VG) sticks or fails due to carbon buildup, causing loss of exhaust brake function, reduced turbo performance, limp mode, and DTC codes P2263 or P006A. TSB 14-001-21 addresses VGT actuator calibration. Actuator replacement costs $800-1,500; complete turbo replacement is $2,500-4,000.
Common Symptoms
- Exhaust brake not engaging or weak braking effect
- Check engine light with turbo codes (P2263, P006A, P0299)
- Reduced engine power / limp mode
- Black smoke from exhaust under acceleration
- Turbo whistle or surge at idle
- Slow turbo spool-up / turbo lag
- Exhaust brake light blinking
How to Fix
For sticking actuator: Remove and clean the VGT actuator and turbo vanes of carbon deposits. Actuator exercise procedure via wiTECH can help prevent sticking. Check TSB 14-001-21 for actuator calibration procedure. If the actuator motor is failed, replace the electronic actuator assembly ($800-1,500, Holset 5497296 or 5610723). If turbo vanes are severely carboned or damaged, complete turbo replacement is needed ($2,500-4,000). Regular highway driving helps keep vanes clean; trucks that idle excessively build up carbon faster.
The 5.7L HEMI engine with Multi-Displacement System (MDS) can experience premature lifter and camshaft wear. The MDS deactivation lifters are prone to failure, causing ticking, misfires, and in severe cases, camshaft lobe damage. This issue has led to class action lawsuits.
Common Symptoms
- Ticking noise at idle
- Engine misfire codes P0300-P0308
- Check engine light
- Loss of power
- Rough idle
- Tick worse when cold
How to Fix
For early detection: Use quality synthetic oil and change every 5,000 miles. Install an MDS delete kit ($200-400) to prevent future failures. If lifters have failed: Full lifter replacement with non-MDS lifters ($2,000-3,500). If camshaft is damaged, expect $3,500-5,500 for full repair. Consider a tuner to disable MDS electronically.
Owner tips & cautions
- TipDIY repairs can save significantly - dealer charges $200-400 but DIY costs are typically 50-70% less
- TipInstall an MDS delete kit ($200-400) to prevent future failures.
- WarningThis is a high-severity issue - ignoring it can lead to costly repairs or safety concerns. Address it promptly.
Sources for this issue (5)
Early-production 2025 RAM 1500 trucks equipped with the new 3.0L Hurricane twin-turbocharged inline-six (Standard Output 420 hp and High Output 540 hp) are widely reported to throw check-engine lights and random/multi-cylinder misfire codes, often on cold start or under load in hot weather. Owners on the 5thGenRams and RamForum communities report P0300 (and per-cylinder P0301-P0306) within the first few thousand miles. Stellantis has issued multiple software TSBs (e.g., 08-055-25 for HO, 08-031-25 for SO, and a cold-start update) that reflash the ignition system control module (ISCM) and PCM; a separate TSB (09-025-25) addresses a purge-line/vacuum-leak source of lean misfires. This is a new-engine, new-generation problem outside the existing HEMI-focused coverage.
Common Symptoms
- Check engine light
- Engine misfire / stumble
- Rough idle
- Hesitation under acceleration
- Misfire codes on cold start
How to Fix
Have the dealer apply the latest ISCM/PCM software per the applicable misfire TSB (HO vs SO calibration). Inspect and reseat the EVAP purge line and the air-intake hose at the airbox for vacuum leaks (TSB 09-025-25). Many owners report running 91+ octane reduces misfire events in hot weather. If reflash and vacuum-leak repairs do not resolve it, dealer should diagnose ignition coils/injectors under powertrain warranty.
Sources for this issue (3)
The 4.7L PowerTech V8 is intolerant of overheating and neglected coolant. Head gaskets leak combustion gases into the cooling system (air in coolant, coolant pushed from the overflow, steam/coolant smell from the exhaust on cold start). Once the aluminum heads warp or a corrosion channel opens between a water jacket and a cylinder, the machined-in valve seats can drop, causing catastrophic misfire and internal damage. A block/combustion-gas test in the coolant confirms it.
Common Symptoms
- Coolant loss with no visible leak
- Air/bubbling in cooling system, coolant pushed from overflow
- White steam or coolant smell from tailpipe on cold start
- Overheating
- Rough idle / misfire after an overheat event
- Milky oil in severe cases
How to Fix
Do a combustion-leak (block) test to confirm. Fix requires head gasket replacement with resurfaced or new cylinder heads (dropped valve seats mean a rebuilt/new head, not just a gasket). Use a Mopar/Fel-Pro MLS head gasket set and always replace the thermostat, water pump and radiator, and flush the cooling system on schedule to prevent recurrence. Parts+labor typically $1,500-$3,500 depending on head damage.
What you need to fix it
Only diagnosis- and fitment-reviewed repair parts are linked here.
- Fel-Pro HS26157PT head gasket set
Do not use for 2004-2009.
- Fel-Pro HS26157PT1 head gasket set
2004-2007 Dodge Ram 1500 4.7L catalog branch, HS26157PT1; confirm VIN/valve-cover configuration.
- HS26157PT2-pattern 4.7L head gasket set
2008-2009 Dodge Ram 1500 4.7L within seller's 2008-2010 coverage; Replacement 598-237/interchange HS26157PT2. Fitment/availability: 81 shown in stock with add-to-cart live at review
- Fel-Pro ES71129 cylinder-head bolt set
Confirm VIN and bolt count/length before order.
- Zerex G-05 50/50 HOAT coolant, one gallon
G-05 HOAT chemistry for compatible 2002-2009 Chrysler applications; verify the owner's manual/current fill and do not mix incompatible coolant.
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Sources for this issue (2)
On 2003-2008 5.7L HEMI engines the cylinder-head valve-seat bores were machined without sufficient interference fit. Combined with localized coolant boiling and hot spots in the heads, an exhaust or intake valve seat can spin loose and drop into the combustion chamber. When the seat drops it is hammered by the valve and piston, causing a sudden misfire, loss of power, a heavy metallic knock, and in many cases destruction of the piston, valve and head. This is distinct from the well-known exhaust-manifold-bolt tick and the later MDS lifter/cam failure; it is a structural cylinder-head defect specific to pre-2009 (pre-Eagle) HEMIs. Overheating events dramatically raise the risk. The 2009 Eagle HEMI revision used improved seat material and tighter machining and largely eliminated the failure.
Common Symptoms
- Sudden single-cylinder misfire (P0301-P0308)
- Loud metallic knocking or clattering
- Significant loss of power
- Rough idle and shaking
- Check engine light flashing
- History of an overheating event before failure
How to Fix
There is no patch repair for a dropped seat. The affected cylinder head (often both) must be replaced or rebuilt with upgraded seats; if the piston or valvetrain is damaged, a long-block or complete engine replacement is required. Owners keeping a pre-2009 HEMI should avoid overheating, maintain the cooling system rigorously, and address any cooling-system weakness or persistent misfire (P0301-P0308) immediately. When replacing one head, many shops replace both heads plus the timing set and oil pump, which are also known weak points on this engine family.
What you need to fix it
Only diagnosis- and fitment-reviewed repair parts are linked here.
- Spartan 2DK1L remanufactured left 5.7L cylinder head
Confirm 2003-2004 separately, VIN, EGR provision, casting and core terms.
- Genuine Mopar 53021616BA early 5.7L cylinder head
Verify VIN, side and casting before order.
- Fel-Pro 260-3145 full engine gasket set
2003-2008 Dodge Ram 1500 5.7L V8 as listed; confirm included head gaskets and obtain the correct new head-bolt sets separately.
- Mopar 53021581AC non-VVT timing-chain set
2005-2008 5.7L non-VVT HEMI; seller explicitly says it does not fit 2009+ VVT engines. Confirm the 2003-2004 application separately.
- Genuine Mopar 53021622AF early 5.7L oil pump
Verify VIN and pickup/front-cover compatibility.
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Sources for this issue (3)
Gas RAM 2500s with the 6.4L (392) HEMI V8 suffer a documented valvetrain defect in which the roller lifter needle bearings fail, the roller stops rolling and drags across the camshaft lobe, wiping out the lobe. The failure is linked to the truck's Multi-Displacement System (MDS/cylinder deactivation): when cylinders are deactivated, oil delivery to the affected lifters is restricted, starving the roller bearings. Owners report onset as a metallic 'HEMI tick' progressing to misfire, dropped cylinder and catastrophic top-end damage. A class-action lawsuit (Petro, et al. v. FCA US LLC, Case No. 1:22-cv-00621, whose named plaintiffs include a 2020 RAM 2500 owner) alleges FCA knew of the defect since at least 2012 and failed to disclose it. There is no safety recall, so repairs typically fall on the owner once warranty lapses.
Common Symptoms
- Metallic ticking/tapping from top of engine (HEMI tick)
- Engine misfire, rough idle
- Check engine light with misfire codes
- Loss of power / dropped cylinder
- Metal shavings in oil
- Loud knocking as failure progresses
How to Fix
Diagnosis via oil-analysis metal content, cylinder-specific misfire/lifter tick, and cam inspection. Accepted repair is replacement of all 16 lifters plus the camshaft (and any damaged pushrods/rockers); severely scored cams or circulated bearing debris often force a long-block or complete engine replacement. Many owners/shops disable/delete MDS during the rebuild to prevent recurrence. Frequent oil changes with correct-spec oil are the preventive measure.
What you need to fix it
Only diagnosis- and fitment-reviewed repair parts are linked here.
- Genuine Mopar 5045517AC 6.4L HD MDS camshaft
2014-2024 Ram 2500 6.4L Heavy Duty HEMI MDS as listed; confirm VIN and production data.
- Genuine Mopar 5038785AD front hydraulic lifters and yoke assembly
6.4L Heavy Duty HEMI with MDS; OE catalog requires quantity two front assemblies for the full engine. Confirm VIN, production date and required quantity.
- Genuine Mopar 5038786AD rear hydraulic lifters and yoke assembly
Confirm VIN and production date and do not treat one assembly as a complete set.
As an Amazon Associate, we earn from qualifying purchases; other part links may also earn au7o a commission. Confirm fitment by VIN before buying.
Sources for this issue (4)
P0302 code reference
General diagnostic-code context. The code alone does not confirm a cause for your vehicle; use the applicable issue card and its sources.
Frequently asked questions
What does P0302 mean on a RAM?
P0302 stands for "Cylinder 2 Misfire Detected." This code means the engine computer has detected a misfire specifically in cylinder 2, meaning that cylinder isn't completing combustion properly on some firing events. The computer watches tiny variations in crankshaft speed to spot when a cylinder fails to fire, and a misfire means the air-fuel mixture isn't igniting correctly — usually from a spark, fuel, or compression problem in that cylinder. You may feel a stumble, rough idle, shaking, loss of power, or a flashing check-engine light, and persistent misfires can damage the catalytic converter. Because it names a single cylinder, the fault is often a component serving just cylinder 2, like its coil, plug, or injector. On RAM it is documented across 4 models: 3500, 1500, 2500, 1500 Classic.
What are the most common causes of P0302?
The most common causes of P0302 are: Worn or fouled spark plug (cylinder 2), Failed ignition coil or coil-on-plug (cylinder 2), Clogged or faulty fuel injector (cylinder 2), Vacuum or intake air leak affecting that cylinder, Low compression (worn rings, burnt/bent valve, head gasket), Damaged spark plug wire or boot (if equipped), Carbon-tracked or cracked coil/plug causing spark loss, Faulty PCM/ECM driver (rare). The specific cause varies by vehicle.
How much does it cost to fix P0302 on a RAM?
Published repair estimates on RAM range from $200 to $12,000 depending on the model and root cause. If an issue mentions a recall or campaign, check your VIN with the manufacturer or NHTSA and confirm eligibility and coverage with a dealer.
Looking for P0302 on a different make?
View P0302 across all makes →Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.