P0300 means your engine's computer has detected misfires occurring across multiple cylinders without a consistent pattern. Unlike cylinder-specific codes (P0301–P0312), P0300 indicates a systemic issue affecting the entire engine rather than one cylinder.
What does P0300 mean?
P0300 means your engine's computer has detected misfires occurring across multiple cylinders without a consistent pattern. Unlike cylinder-specific codes (P0301–P0312), P0300 indicates a systemic issue affecting the entire engine rather than one cylinder.
P0300 is a misfire-related diagnostic trouble code classified as high severity. When your vehicle's ECU detects this condition, it stores P0300 and illuminates the check engine light.
What are the symptoms of P0300?
If your vehicle has triggered P0300, you may notice one or more of these symptoms:
Check engine light flashing (severe misfires) or steady
Rough idle or engine vibration
Hesitation or stumbling during acceleration
Loss of power, especially under load
Increased fuel consumption
Strong fuel smell from exhaust
What causes P0300?
Here are the most common causes of P0300, ranked by how likely they are to be the culprit:
No - address this immediately. Driving with active misfires can damage the catalytic converter within minutes and may cause loss of power at dangerous moments. Pull over safely and address immediately.
How do you diagnose P0300?
Follow these steps to pinpoint the root cause of P0300:
Check for companion codes (P0301–P0312) that indicate which cylinders are misfiring most
Inspect spark plugs for wear, fouling, or damage. Replace if over 50,000 km
Test ignition coils with a multimeter or by swapping coils between cylinders
Perform a vacuum leak test using smoke or propane around intake manifold gaskets and hoses
Check fuel pressure with a gauge. Should hold steady at spec (typically 40–60 PSI)
Run a compression test if other causes are ruled out to check for internal engine damage
How much does P0300 cost to fix?
Repair costs for P0300 vary depending on the root cause and your vehicle. Here are typical estimates:
Repair
Parts Cost
Labor Cost
Total Estimate
DIY Difficulty
Replace spark plugs (full set)
€20–€80
€40–€150
€60–€230
Easy
Replace ignition coil(s)
€30–€200
€40–€120
€70–€320
Moderate
Fix vacuum leak
€10–€80
€60–€200
€70–€280
Moderate
Replace fuel injectors
€100–€400
€100–€300
€200–€700
Professional
Prices estimated as of March 2026. Costs vary by region, vehicle, and shop.
P0300 on specific vehicles
P0300 behaves differently depending on your vehicle. Select your car below for model-specific causes, known issues, and adjusted cost estimates:
P0300 on Toyota Camry
Toyota Camry • 2007–2024
The 2.5L 2AR-FE engine in 2012–2017 Camrys is known for ignition coil failures that trigger P0300. Toyota issued a warranty extension for ignition coils on some model years. The 2GR-FE V6 can also develop intake manifold runner issues causing random misfires.
What causes P0300 on a Toyota Camry?
Toyota CamryIgnition coil failures on 2012–2017 2.5L models (warranty extension available)
Toyota CamryIntake manifold runner control issues on 2GR-FE V6
P0300 on Honda Civic
Honda Civic • 2006–2024
The 1.5L turbo engine (L15B7) in 2016+ Civics has a well-documented fuel dilution issue where gasoline mixes with engine oil, causing misfires and P0300. Honda issued a software update to mitigate this. Earlier R18A engines commonly develop valve adjustment issues causing misfires around 100,000 km.
What causes P0300 on a Honda Civic?
Honda CivicFuel dilution in 1.5L turbo (2016+): check oil level and smell for gasoline
Honda CivicValve adjustment needed on R18A engines at 100,000+ km
P0300 repair cost for Honda Civic
Estimated costs for Honda Civic ownersadjusted lower than average due to Honda-specific parts pricing
Repair
Parts Cost
Labor Cost
Total Estimate
DIY Difficulty
Replace spark plugs (full set)
€18–€72
€36–€135
€54–€207
Easy
Replace ignition coil(s)
€27–€180
€36–€108
€63–€288
Moderate
Fix vacuum leak
€9–€72
€54–€180
€63–€252
Moderate
Replace fuel injectors
€90–€360
€90–€270
€180–€630
Professional
Prices estimated as of March 2026. Costs vary by region, vehicle, and shop.
P0300 on Volkswagen Golf
Volkswagen Golf • 2005–2024
The EA888 2.0T engine in Golf GTI/R models is prone to carbon buildup on intake valves (direct injection), which causes misfires. Walnut blasting every 60,000–80,000 km is recommended. The 1.4 TSI in earlier models has timing chain tensioner failures that can cause P0300.
What causes P0300 on a Volkswagen Golf?
Volkswagen GolfCarbon buildup on intake valves (direct injection, especially EA888 2.0T)
Volkswagen GolfTiming chain tensioner failure on 1.4 TSI (2006–2014)
P0300 repair cost for Volkswagen Golf
Estimated costs for Volkswagen Golf ownersadjusted higher than average due to Volkswagen-specific parts pricing
Repair
Parts Cost
Labor Cost
Total Estimate
DIY Difficulty
Replace spark plugs (full set)
€23–€92
€46–€173
€69–€265
Easy
Replace ignition coil(s)
€35–€230
€46–€138
€81–€368
Moderate
Fix vacuum leak
€12–€92
€69–€230
€81–€322
Moderate
Replace fuel injectors
€115–€460
€115–€345
€230–€805
Professional
Prices estimated as of March 2026. Costs vary by region, vehicle, and shop.
P0300 on BMW 3 Series
BMW 3 Series • 2006–2024
The N54 twin-turbo engine is notorious for failing ignition coils and spark plugs that trigger P0300. Many owners replace coils every 50,000 km as preventive maintenance. The B48 engine in newer 330i models can develop high-pressure fuel pump issues causing random misfires under load.
What causes P0300 on a BMW 3 Series?
BMW 3 SeriesN54 ignition coil failures (replace every 50,000 km as maintenance)
BMW 3 SeriesB48 high-pressure fuel pump issues causing misfires under load
P0300 repair cost for BMW 3 Series
Estimated costs for BMW 3 Series ownersadjusted higher than average due to BMW-specific parts pricing
Repair
Parts Cost
Labor Cost
Total Estimate
DIY Difficulty
Replace spark plugs (full set)
€28–€112
€56–€210
€84–€322
Easy
Replace ignition coil(s)
€42–€280
€56–€168
€98–€448
Moderate
Fix vacuum leak
€14–€112
€84–€280
€98–€392
Moderate
Replace fuel injectors
€140–€560
€140–€420
€280–€980
Professional
Prices estimated as of March 2026. Costs vary by region, vehicle, and shop.
Related diagnostic codes
These codes are often seen alongside P0300 or indicate related issues:
No. A flashing check engine light with P0300 means severe misfires that can destroy your catalytic converter within minutes. Even with a steady light, misfires cause unburned fuel to enter the exhaust, overheating the converter. Address this code promptly.
Why does P0300 come and go?
Intermittent P0300 often points to early-stage ignition component failure, a marginal vacuum leak that worsens when the engine is hot, or fuel quality issues. The pattern may worsen over time as components continue to degrade.
What is the difference between P0300 and P0301?
P0300 means misfires are detected across multiple or random cylinders. P0301 specifically means cylinder 1 is misfiring. If you see P0300 alongside cylinder-specific codes, focus on the specific cylinders first.
Can bad fuel cause P0300?
Yes. Contaminated or low-octane fuel can cause random misfires. If P0300 appeared shortly after refueling, try adding a fuel system cleaner and filling with premium fuel. If it clears after a tank or two, bad fuel was likely the cause.
