What exactly is code P0300 and why does it happen?

Code P0300 is an OBD-II diagnostic trouble code that indicates “Random/Multiple Cylinder Misfire Detected.” This means your engine’s computer has detected that multiple cylinders are not firing properly or misfires are occurring in random patterns across different cylinders. Unlike specific cylinder codes (P0301, P0302, etc.), P0300 indicates the problem affects more than one cylinder or occurs randomly. Misfires happen when the combustion process fails due to problems with spark, fuel delivery, air intake, or engine compression.

How do I know if my car has a P0300 problem?

Key symptoms include: a flashing or steady check engine light, rough engine idle that makes the car shake or vibrate, poor acceleration with hesitation or jerky motion, difficulty starting the engine, and noticeably worse fuel economy. The most critical warning sign is a flashing check engine light – this indicates severe misfires that can damage your catalytic converter and requires immediate attention. You may also hear unusual engine noises, experience stalling, or notice your car lacks power during acceleration.

Is this something I can fix myself, or do I need a professional?

DIY suitable if: you have experience with automotive electrical and fuel systems, own proper diagnostic tools, and the problem is simple (like worn spark plugs). Call a professional if: your check engine light is flashing, you’re not comfortable working with high-voltage ignition systems or pressurized fuel lines, the problem involves engine mechanical issues, or multiple diagnostic codes are present. Required skill level: intermediate to advanced. P0300 diagnosis requires systematic testing and can involve complex interactions between multiple engine systems.

Why is my engine misfiring on multiple cylinders?

Most common causes: worn or fouled spark plugs affecting multiple cylinders, failing ignition coils or coil packs, vacuum leaks that disrupt the air-fuel mixture, clogged or malfunctioning fuel injectors, or contaminated fuel. Less common but serious causes include low engine compression from worn piston rings or valves, timing chain or belt problems, failed mass airflow sensor, or engine control module issues. The random nature suggests system-wide problems rather than isolated component failures.

What tools do I need to diagnose this problem?

Essential tools: OBD-II scanner capable of reading live data and freeze-frame information, basic multimeter for electrical testing, spark plug socket set, and compression tester. Professional-level tools for complete diagnosis: ignition analyzer or oscilloscope, fuel pressure tester, smoke machine for vacuum leak detection, and professional diagnostic scanner with bi-directional capabilities. Where to find: auto parts stores often loan basic tools, while professional equipment may require shop access or rental.

What causes ignition coil failure and how can I prevent it?

Root causes: heat exposure from engine operation gradually breaks down coil insulation, vibration stress from engine operation, electrical stress from worn spark plugs that require higher voltage, and oil contamination from valve cover gasket leaks. Prevention strategies: replace spark plugs at recommended intervals to reduce coil stress, fix oil leaks promptly to prevent coil contamination, and avoid aftermarket performance modifications that stress the ignition system. Risk factors: high-mileage vehicles, severe driving conditions, and deferred maintenance increase coil failure likelihood.

Can I drive with a P0300 code, and for how long?

Flashing check engine light: Stop driving immediately – severe misfires can cause catalytic converter damage and create safety hazards. Steady check engine light: Limit driving to essential trips only and schedule repair within a few days. Driving risks: reduced engine power makes highway driving dangerous, unpredictable engine performance can cause accidents, and continued operation causes expensive secondary damage. Maximum distance: If you must drive with steady light, limit to short trips under 20 miles at low speeds, but seek repair immediately.

P03XX Codes – Ignition System or Misfire

This list includes all P03XX codes related to ignition system faults and engine misfires. Diagnose coil pack failures, spark plug issues, and random or cylinder-specific misfire conditions.

OBD II P03XX Ignition System & Misfire Table with Search

DTC Number	DTC Naming	Location
P0300	Random/Multiple Cylinder Misfire Detected
P0301	Cylinder 1 Misfire Detected
P0302	Cylinder 2 Misfire Detected
P0303	Cylinder 3 Misfire Detected
P0304	Cylinder 4 Misfire Detected
P0305	Cylinder 5 Misfire Detected
P0306	Cylinder 6 Misfire Detected
P0307	Cylinder 7 Misfire Detected
P0308	Cylinder 8 Misfire Detected
P0309	Cylinder 9 Misfire Detected
P030A	ISO/SAE Reserved
P030B	ISO/SAE Reserved
P030C	ISO/SAE Reserved
P030D	ISO/SAE Reserved
P030E	ISO/SAE Reserved
P030F	ISO/SAE Reserved
P0310	Cylinder 10 Misfire Detected
P0311	Cylinder 11 Misfire Detected
P0312	Cylinder 12 Misfire Detected
P0313	Misfire Detected With Low Fuel
P0314	Single Cylinder Misfire (Cylinder not Specified)
P0315	Crankshaft Position System Variation Not Learned
P0316	Engine Misfire Detected on Startup (First 1000 Revolutions)
P0317	Rough Road Hardware Not Present
P0318	Rough Road Sensor "A" Signal Circuit
P0319	Rough Road Sensor "B" Signal Circuit
P031A	ISO/SAE Reserved
P031B	ISO/SAE Reserved
P031C	ISO/SAE Reserved
P031D	ISO/SAE Reserved
P031E	ISO/SAE Reserved
P031F	ISO/SAE Reserved
P0320	Ignition/Distributor Engine Speed Input Circuit
P0321	Ignition/Distributor Engine Speed Input Circuit Range/Performance
P0322	Ignition/Distributor Engine Speed Input Circuit No Signal
P0323	Ignition/Distributor Engine Speed Input Circuit Intermittent
P0324	Knock Control System Error
P0325	Knock Sensor 1 Circuit	Bank 1 or Single Sensor
P0326	Knock Sensor 1 Circuit Range/Performance	Bank 1 or Single Sensor
P0327	Knock Sensor 1 Circuit Low	Bank 1 or Single Sensor
P0328	Knock Sensor 1 Circuit High	Bank 1 or Single Sensor
P0329	Knock Sensor 1 Circuit Intermittent	Bank 1 or Single Sensor
P032A	Knock Sensor 3 Circuit	Bank 1
P032B	Knock Sensor 3 Circuit Range/Performance	Bank 1
P032C	Knock Sensor 3 Circuit Low	Bank 1
P032D	Knock Sensor 3 Circuit High	Bank 1
P032E	Knock Sensor 3 Circuit Intermittent	Bank 1
P032F	ISO/SAE Reserved
P0330	Knock Sensor 2 Circuit	Bank 2
P0331	Knock Sensor 2 Circuit Range/Performance	Bank 2
P0332	Knock Sensor 2 Circuit Low	Bank 2
P0333	Knock Sensor 2 Circuit High	Bank 2
P0334	Knock Sensor 2 Circuit Intermittent	Bank 2
P0335	Crankshaft Position Sensor "A" Circuit
P0336	Crankshaft Position Sensor "A" Circuit Range/Performance
P0337	Crankshaft Position Sensor "A" Circuit Low
P0338	Crankshaft Position Sensor "A" Circuit High
P0339	Crankshaft Position Sensor "A" Circuit Intermittent
P033A	Knock Sensor 4 Circuit	Bank 2
P033B	Knock Sensor 4 Circuit Range/Performance	Bank 2
P033C	Knock Sensor 4 Circuit Low	Bank 2
P033D	Knock Sensor 4 Circuit High	Bank 2
P033E	Knock Sensor 4 Circuit Intermittent	Bank 2
P033F	ISO/SAE Reserved
P0340	Camshaft Position Sensor "A" Circuit	Bank 1 or Single Sensor
P0341	Camshaft Position Sensor "A" Circuit Range/Performance	Bank 1 or Single Sensor
P0342	Camshaft Position Sensor "A" Circuit Low	Bank 1 or Single Sensor
P0343	Camshaft Position Sensor "A" Circuit High	Bank 1 or Single Sensor
P0344	Camshaft Position Sensor "A" Circuit Intermittent	Bank 1 or Single Sensor
P0345	Camshaft Position Sensor "A" Circuit	Bank 2
P0346	Camshaft Position Sensor "A" Circuit Range/Performance	Bank 2
P0347	Camshaft Position Sensor "A" Circuit Low	Bank 2
P0348	Camshaft Position Sensor "A" Circuit High	Bank 2
P0349	Camshaft Position Sensor "A" Circuit Intermittent	Bank 2
P034A	ISO/SAE Reserved
P034B	ISO/SAE Reserved
P034C	ISO/SAE Reserved
P034D	ISO/SAE Reserved
P034E	ISO/SAE Reserved
P034F	ISO/SAE Reserved
P0350	Ignition Coil Primary/Secondary Circuit
P0351	Ignition Coil "A" Primary/Secondary Circuit
P0352	Ignition Coil "B" Primary/Secondary Circuit
P0353	Ignition Coil "C" Primary/Secondary Circuit
P0354	Ignition Coil "D" Primary/Secondary Circuit
P0355	Ignition Coil "E" Primary/Secondary Circuit
P0356	Ignition Coil "F" Primary/Secondary Circuit
P0357	Ignition Coil "G" Primary/Secondary Circuit
P0358	Ignition Coil "H" Primary/Secondary Circuit
P0359	Ignition Coil "I" Primary/Secondary Circuit
P035A	ISO/SAE Reserved
P035B	ISO/SAE Reserved
P035C	ISO/SAE Reserved
P035D	ISO/SAE Reserved
P035E	ISO/SAE Reserved
P035F	ISO/SAE Reserved
P0360	Ignition Coil "J" Primary/Secondary Circuit
P0361	Ignition Coil "K" Primary/Secondary Circuit
P0362	Ignition Coil "L" Primary/Secondary Circuit
P0363	Misfire Detected - Fueling Disabled
P0364	ISO/SAE Reserved
P0365	Camshaft Position Sensor "B" Circuit	Bank 1
P0366	Camshaft Position Sensor "B" Circuit Range/Performance	Bank 1
P0367	Camshaft Position Sensor "B" Circuit Low	Bank 1
P0368	Camshaft Position Sensor "B" Circuit High	Bank 1
P0369	Camshaft Position Sensor "B" Circuit Intermittent	Bank 1
P036A	ISO/SAE Reserved
P036B	ISO/SAE Reserved
P036C	ISO/SAE Reserved
P036D	ISO/SAE Reserved
P036E	ISO/SAE Reserved
P036F	ISO/SAE Reserved
P0370	Timing Reference High Resolution Signal "A"
P0371	Timing Reference High Resolution Signal "A" Too Many Pulses
P0372	Timing Reference High Resolution Signal "A" Too Few Pulses
P0373	Timing Reference High Resolution Signal "A" Intermittent/Erratic
P0374	Timing Reference High Resolution Signal "A" No Pulses
P0375	Timing Reference High Resolution Signal "B"
P0376	Timing Reference High Resolution Signal "B" Too Many Pulses
P0377	Timing Reference High Resolution Signal "B" Too Few Pulses
P0378	Timing Reference High Resolution Signal "B" Intermittent/Erratic Pulses
P0379	Timing Reference High Resolution Signal "B" No Pulses
P037A	ISO/SAE Reserved
P037B	ISO/SAE Reserved
P037C	ISO/SAE Reserved
P037D	Glow Plug Sense Circuit
P037E	Glow Plug Sense Circuit Low
P037F	Glow Plug Sense Circuit High
P0380	Glow Plug/Heater Circuit "A"
P0381	Glow Plug/Heater Indicator Circuit
P0382	Glow Plug/Heater Circuit "B"
P0383	Glow Plug Control Module Control Circuit Low
P0384	Glow Plug Control Module Control Circuit High
P0385	Crankshaft Position Sensor "B" Circuit
P0386	Crankshaft Position Sensor "B" Circuit Range/Performance
P0387	Crankshaft Position Sensor "B" Circuit Low
P0388	Crankshaft Position Sensor "B" Circuit High
P0389	Crankshaft Position Sensor "B" Circuit Intermittent
P038A	ISO/SAE Reserved
P038B	ISO/SAE Reserved
P038C	ISO/SAE Reserved
P038D	ISO/SAE Reserved
P038E	ISO/SAE Reserved
P038F	ISO/SAE Reserved
P0390	Camshaft Position Sensor "B" Circuit	Bank 2
P0391	Camshaft Position Sensor "B" Circuit Range/Performance	Bank 2
P0392	Camshaft Position Sensor "B" Circuit Low	Bank 2
P0393	Camshaft Position Sensor "B" Circuit High	Bank 2
P0394	Camshaft Position Sensor "B" Circuit Intermittent	Bank 2
P0395 – P03FF	ISO/SAE Reserved
Code not found