2024 Subaru P0300: What It Means & Is It Safe to Drive?
P0300 on the 2024 Subaru: Random/Multiple Cylinder Misfire Detected. Here's what it means, what usually causes it, what repairs typically cost, and whether it's safe to keep driving.
What this code means
The PCM has detected misfires across multiple cylinders. This can cause damage to the catalytic converter if driven for long.
Common causes on the 2024 Subaru
- Worn spark plugs or ignition coils
- Clogged or bad fuel injectors
- Low compression
- Vacuum leak, bad MAF, or fuel delivery issue
Symptoms
- Check Engine Light (often flashing under load)
- Rough idle, shaking, loss of power
- Possible smell of unburned fuel
Typical fixes
- Replace spark plugs and coils as needed
- Clean or replace fuel injectors
- Fix vacuum/fuel issues
- Compression test if no obvious cause
Repair cost range
For a 2024 Subaru, repairs for P0300 typically fall between $150 and $1200, depending on the root cause and labor rates in your area.
Known issues on Subaru
Subaru P0300 on EJ25 SOHC naturally aspirated engines should immediately trigger a head gasket investigation—Subaru EJ25 head gaskets leak coolant into the combustion chamber causing hydrolock-style misfires. Look for white exhaust smoke, coolant loss, and elevated coolant pressure. On WRX EJ257 turbocharged, P0300 under boost is a head gasket failure until proven otherwise—this is a known failure mode and a very serious condition. On FA20 (BRZ/FR-S), P0300 is less common and usually traces to worn spark plugs or an oil separator failure.
Most commonly affected models