P0300 on Dodge: How to Diagnose & Fix
Random/Multiple Cylinder Misfire Detected
10 Dodge models · 17 documented issues · 9 critical · $40-$15,000 repair
P0300 on Dodge by model: symptoms, diagnosis and fix
HEMI engines with Multi-Displacement System (MDS) can develop a ticking noise from the MDS lifters. This is most noticeable at idle and during light acceleration. While often not immediately harmful, it can indicate lifter wear.
Common Symptoms
- Ticking noise at idle
- Tick that follows engine RPM
- Noise louder when warm
- Tick comes and goes
- Sound from top of engine
How to Fix
Use quality synthetic oil meeting Chrysler MS-6395 spec. MDS delete kit available for permanent solution. Some owners have had lifters replaced under extended warranty. Regular oil changes help minimize tick.
What you need to fix it
Only diagnosis- and fitment-reviewed repair parts are linked here.
- Mopar 53022263AF 5.7L HEMI MDS/VVT camshaft
Replace only when inspection shows lifter-related lobe damage Fitment: Verified 5.7L branch; not the 6.4L camshaft Live OEM direct product page when checked
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 (1)
HEMI engines with Multi-Displacement System (MDS) can develop a ticking noise from the MDS lifters. This tick is most noticeable at idle and during light acceleration. While often not causing immediate damage, it can indicate lifter wear that may eventually require attention.
Common Symptoms
- Ticking noise at idle
- Tick that follows engine RPM
- Noise louder when engine is warm
- Tick comes and goes
- Noise from top of engine
How to Fix
Use quality synthetic oil meeting Chrysler MS-6395 spec. Consider MDS delete kit if desired permanent solution. Some owners have had lifters replaced under extended warranty. Regular oil changes help minimize tick.
What you need to fix it
Only diagnosis- and fitment-reviewed repair parts are linked here.
- Genuine Mopar 53022298AB Multiple Displacement Solenoid
Replace only when testing shows the solenoid/control branch is faulty rather than a collapsed lifter or worn cam Fitment: 2010-2024 5.7L/6.4L MDS applications per live title; confirm the vehicle actually has MDS Live direct US performanc…
Sources for this issue (1)
The 3.6L Pentastar V6 can develop a ticking noise often related to the rocker arms or hydraulic lifters. This is common on engines with higher mileage or irregular oil change intervals. Some early Pentastar engines had rocker arm design issues that were later updated.
Common Symptoms
- Ticking noise at startup
- Tick that varies with RPM
- Noise from valve cover area
- Check engine light with misfire codes
- Rough idle in severe cases
How to Fix
Use quality synthetic oil and change regularly. If tick is severe, rocker arms may need replacement with updated design. Some owners have had success with engine flush treatments. Check for TSBs related to your model year.
Sources for this issue (1)
Some 2015-2021 Dodge Challenger 5.7L and 6.4L engines can develop a persistent engine-speed-related tick, rough idle, loss of power, or misfire from hydraulic roller-lifter, roller, or cam-lobe wear. A tick alone does not prove internal wear: exhaust-manifold leakage, injector noise, oil-pressure concerns, and other causes must be ruled out. MDS fitment is transmission-specific, not engine-name-wide: automatic 5.7L and 6.4L applications use cylinder deactivation, while six-speed manual applications are non-MDS. Cam and lifter wear is not limited to MDS hardware.
Common Symptoms
- Ticking noise at idle
- Tick goes away when engine warms up
- Tick more prominent on cold start
- Noise from top of engine
How to Fix
Retrieve DTC and misfire data, localize the noise, and check for exhaust-manifold leakage before buying internal parts. If cam/lifter wear is suspected, inspect the lifter rollers and cam lobes and check the VVT oil-control-valve screen for metal debris. FCA STAR case S1709000010 directs camshaft/lifter replacement when wear is confirmed and no screen debris is present; debris can indicate that a larger repair or engine replacement is required. Use the lifter type that matches the factory transmission/MDS configuration and verify by VIN. A stock automatic-MDS full-engine service set requires two front 5038785AD packs and two rear 5038786AD packs. A factory non-MDS/manual full-engine set requires four OEM 5038784AD packs, or an exact retailer bundle of sixteen lifters and four yokes. On an automatic-MDS car, non-MDS lifters are only one part of a complete engineered mechanical delete with compatible cam/supporting parts and calibration. Correct oil and electronic MDS disabling do not repair a worn lifter, roller, or camshaft.
What you need to fix it
Only diagnosis- and fitment-reviewed repair parts are linked here.
- Genuine Mopar 5038785AD front MDS hydraulic lifters and yoke pack
Front-position MDS lifter pack for a confirmed MDS valvetrain repair after the heads are removed and roller/cam damage is inspected Fitment: Live fitment lists 2009-2023 Challenger 5.7L/6.4L, but the year-specific catalog specifies MDS/f…
- Genuine Mopar 5038786AD rear MDS hydraulic lifters and yoke pack
Rear-position companion pack for a complete factory-MDS lifter repair Fitment: Live fitment lists 2009-2023 Challenger 5.7L/6.4L; pair with the front packs only on a verified MDS engine, and confirm that two front plus two rear packages …
- Genuine Mopar 5038784AD complete non-MDS HEMI lifter/yoke bundle
Complete lifter branch for a factory non-MDS/manual-transmission 5.7L or 6.4L after cam and roller inspection confirms replacement Fitment: Live bundle explicitly contains 16 lifters and four yokes and lists 2015-2023 Challenger 5.7L/6.4…
- Genuine Mopar 53022372AA 5.7L MDS/VVT camshaft
Camshaft replacement when lifter-roller failure has visibly or measurably damaged a lobe on the verified 5.7L MDS engine Fitment: Year-specific catalogs identify this as the 5.7L MDS cam; direct fitment lists 2009-2023 Challenger 5.7L. D…
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 (1)
The 3.6L Pentastar V6 engine can develop a ticking noise from worn rocker arms. Unlike the HEMI MDS tick, this is caused by the roller follower rocker arms wearing out prematurely. The issue typically appears between 50,000-100,000 miles and is more common on 2011-2013 engines but can occur on later models.
Common Symptoms
- Ticking noise from engine at idle
- Tick may worsen when engine is warm
- Check engine light for misfire codes
- Rough idle in severe cases
- Ticking noise changes with RPM
How to Fix
Replace the affected rocker arms. Many owners replace all 24 rocker arms preventatively when doing this repair ($400-800 for parts). Labor is 4-6 hours ($400-600). Total repair cost is typically $800-1,400. Using quality synthetic oil and regular oil changes can help prevent premature wear.
What you need to fix it
Only diagnosis- and fitment-reviewed repair parts are linked here.
- Mopar 5184296AH valve rocker arm
Replacement for each rocker whose roller, bearing or contact surface is confirmed faulty after the valve cover is removed and the cam lobes are inspected Fitment: Live OEM fitment lists 2011-2023 Challenger 3.6L and the year catalog requ…
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 (1)
A P0420 ("Catalyst System Efficiency Below Threshold, Bank 1") or P0430 ("Bank 2") check-engine light is one of the most common emissions codes on the Dodge Challenger, especially on higher-mileage V8 cars. The PCM sets the code when it compares the upstream (pre-cat) and downstream (post-cat) oxygen-sensor signals: if the downstream sensor begins to mimic the rapidly-switching upstream sensor instead of staying relatively flat, the computer concludes the converter is no longer storing/releasing oxygen efficiently. On the Challenger this code is frequently NOT a worn-out converter at all. The two most common upstream root causes are (1) an exhaust leak from broken exhaust-manifold bolts — the well-documented "HEMI tick" on the 5.7L and 6.4L V8s — which lets atmospheric oxygen into the exhaust stream and confuses the rear O2 sensor, and (2) a long-running misfire (worn plugs, failing coils, leaking injectors on the 3.6L Pentastar) that dumps raw fuel into the converter and physically destroys it over time. A failed downstream O2 sensor, contaminated converter (from an oil-cooler/oil-filter-housing leak on the Pentastar), or simply an aged/degraded cat round out the causes. Chrysler also issued software bulletins (TSB 18-021-12, superseded by 18-033-13) because early PCM calibration logic was overly sensitive and could trigger false P0420/P0430 codes — particularly in warm weather or on long highway drives — so a PCM reflash should be ruled out before any hardware is replaced. Because the converter sits in the federal/CARB emissions-warranty window for many of these cars, the diagnosis order matters a lot to the owner's wallet.
Common Symptoms
- Check Engine Light on with stored code P0420 (Bank 1) and/or P0430 (Bank 2)
- Vehicle may run normally with no obvious driveability change at first
- Failed state emissions / smog inspection
- Possible rotten-egg (sulfur) smell from a degrading converter
- Slight loss of power or fuel economy if the converter is partially clogged
- Often accompanied by a cold-start exhaust tick (broken manifold bolts) on the V8
- Code returns shortly after clearing if root cause is not fixed
How to Fix
Diagnose before you spend. (1) Pull all stored codes first — if any misfire (P0300-P030x) or O2-sensor codes are also present, fix those first, since a misfire will quickly kill a new converter. (2) Inspect for exhaust leaks, especially broken exhaust-manifold bolts on the 5.7L/6.4L V8 (look for soot/ticking at the manifold flanges); repair the leak and clear the code before condemning the cat — a manifold leak is a very common false-trigger of P0420 on the HEMI. (3) Check for a PCM software update at the dealer per TSB 18-021-12 / 18-033-13, which addresses incorrectly-set P0420/P0430 codes. (4) Graph the oxygen sensors with a scan tool: the downstream (Bank 1 Sensor 2 / Bank 2 Sensor 2) signal should be slow and steady; if it copies the fast-switching upstream sensor, the converter is failed. A failing downstream O2 sensor is a much cheaper part to try than a converter. (5) Only after ruling out leaks, misfires, software and sensors should the catalytic converter be replaced. Use an OEM Mopar or quality CARB-compliant aftermarket (e.g., MagnaFlow) unit; cheap universal cats often re-trigger the code. On the 3.6L Pentastar, also confirm the oil-filter-housing/oil-cooler is not leaking oil into the system, as that contamination will destroy a new converter. Note: the converter is covered under the federal 8-year/80,000-mile emissions warranty (and 15-year/150,000-mile in California) on many of these model years — check before paying out of pocket.
What you need to fix it
Only diagnosis- and fitment-reviewed repair parts are linked here.
- OBDLink MX+ Bluetooth OBD-II adapter with included apps
Graph upstream and downstream oxygen-sensor behavior and fuel-trim data after misfires and exhaust leaks are repaired, before condemning a converter Fitment: Generic OBD-II live-data tool; confirm the app exposes the required PIDs on the…
- Genuine Mopar 5149180AB oxygen sensor
Sensor branch only when waveform, heater-circuit and wiring tests identify the exact failed sensor rather than converter inefficiency Fitment: Live fitment lists 2011-2023 Challenger 3.6L/5.7L/6.2L/6.4L, but catalog position varies by ye…
- MagnaFlow 16420 OEM-grade federal/EPA direct-fit catalytic converter assembly
Confirm engine family and local emissions rules $911.90 with Add to Cart on the live US retailer page when checked
- Genuine Mopar 6509863AA exhaust-manifold stud
Repair an identified 5.7L manifold fastener leak before evaluating converter efficiency again Fitment: 2009-2020 Challenger 5.7L side-position stud, sold individually; other engines and positions require their own hardware $11.65 and Add…
- Fel-Pro MS97083 exhaust-manifold gasket set
Reseal a confirmed 5.7L manifold-to-head leak before interpreting catalyst-monitor data Fitment: 5.7L HEMI branch only after vehicle fitment confirmation; not the 6.1L/6.2L/6.4L gasket $56.99 and Add to Cart on the live AutoZone US produ…
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 (1)
P0300 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 P0300 mean on a Dodge?
P0300 stands for "Random/Multiple Cylinder Misfire Detected." P0300 means the engine computer detected misfires occurring randomly or across multiple cylinders rather than in one specific cylinder. A misfire is when a cylinder fails to ignite its fuel-air mixture properly, which the computer senses through small fluctuations in crankshaft speed. Because it's not isolated to one cylinder, the cause is usually something that affects the whole engine — like fuel, air, or ignition system problems — rather than a single coil or plug. Persistent or heavy misfiring wastes fuel, runs rough, and can damage the catalytic converter, which is why a flashing check engine light should be taken seriously. On Dodge it is documented across 10 models: Durango, Charger, Challenger, Intrepid, Ram 1500, Stratus, Grand Caravan, Journey, Viper, Neon.
What are the most common causes of P0300?
The most common causes of P0300 are: Worn or fouled spark plugs (across cylinders), Vacuum or intake air leak, Weak fuel pump, clogged fuel filter, or low fuel pressure, Failing ignition coils or worn spark plug wires, Dirty or faulty mass airflow (MAF) sensor, Clogged or dirty fuel injectors, Faulty crankshaft/camshaft position sensor, Low compression or EGR/PCV system faults. The specific cause varies by vehicle.
How much does it cost to fix P0300 on a Dodge?
Published repair estimates on Dodge range from $40 to $15,000 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 P0300 on a different make?
View P0300 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.