P0302 Code: Meaning, Symptoms, Causes (& How to Fix it)

The proper combustion of the air-fuel mixture is very important for the efficient working of the engine. When your air-fuel mixture doesn’t burn properly, your engine starts misfiring. A misfire can be easily noticed by retrieving the activation code from the car’s onboard diagnostics system. These trouble codes represent particular conditions and are generally related to the affected cylinder(s). The diagnostic trouble code (DTC) P0302 represents a misfiring in cylinder 2. This article mainly explains the P0302 code symptoms, causes, and fixing costs.

P0302 Code Definition

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The P0302 code stands for “Cylinder 2 misfire detected.”

What Does the P0302 Code Mean?

The P0302 code indicates that cylinder number 2 is misfiring and not receiving sufficient spark to its spark plug.

P0302 Code

The vehicles most commonly contain four or six cylinders. These cylinders are arranged in different arrangements. The engine cylinder is also known as a combustion chamber. After the compression process, the air-fuel mixture is transferred into the engine cylinder.

Each cylinder contains a spark plug. The spark plugs are only used in gasoline engines. In the case of the petrol engine, when the compressed air-fuel mixture enters the cylinder, the spark plug generates an electric spark and ignites the air-fuel mixture. However, in the case of a diesel engine, the air-fuel mixture is ignited due to the high compression of the air.

When the air-fuel mixture burns, it generates power. This power is used to rotate the crankshaft of your engine. The rotation of the crankshaft is further used to turn the flywheel which further turns the vehicle wheels.

Your vehicle’s crankshaft revolutions may decrease or increase if a cylinder misfires. If the rpm/min increases or decreases by more than 2%, your PCM will trigger a trouble code.

If the crankshaft rpm/min is reduced or increased between 2% and 10%, the Check Engine Light will come on. If the crankshaft rpm/min is reduced or increased by more than 10%, the Check Engine Light will start blinking. A blinking Check Engine Light shows a serious misfiring issue. When your powertrain control module (PCM) detects that your engine cylinder number 2 is misfiring, it triggers the P0302 code.

The P0302 code is a part of a series of misfire trouble codes that range from P0300 to P0012. Each code between P0301 and P0312 specifies a misfire on a specific cylinder. For example, code P0301 indicates a misfire on cylinder number 1, and code P0312 indicates a misfire on cylinder number 12.

Causes of P0302 Code

  • Clogged or damaged EGR valves
  • Faulty fuel injectors 
  • Burned or bad engine valves
  • Bad fuel pump
  • Inaccurate ignition timing
  • The bad spark plug in cylinder 2
  • Insufficient fuel
  • Damaged wiring of the cylinder 2 spark plug
  • Damaged distributor cap
  • Head gasket leaks
  • Faulty MAF sensor
  • Faulty fuel pressure sensor
  • Faulty O2 sensor
  • Faulty oil distributor
  • A damaged lifter or worn camshaft lobe 
  • A faulty throttle position sensor
  • Vacuum leaks
  • Bad catalytic converter
  • Faulty crankshaft sensor
  • Poor quality fuel
  • Bad camshaft sensor
  • Low fuel pressure
  • Bad ignition coils in cylinder 2
  • Poor compression in cylinder 2
  • Bad PCM

Symptoms of P0302 Code

  • Engine stalling
  • Fuel smell from the exhaust pipe
  • The vehicle will not start or is difficult to start
  • Poor fuel economy
  • Rough idle
  • Illuminated check engine light
  • Limp mode
  • Misfires
  • A reduction in the engine power
  • Poor car acceleration
  • Jerking when driving

Read More: P0303 Code Symptoms and Causes

How to diagnose the P0302 Code?

  • Use an OBD-II scan tool to check the existence of the P0302.
  • Record all stored fault codes, along with all available freeze frame data. Clear the codes and make a test drive. If the code returns, then check other parts.
  • Inspects the spark plug wire for cylinder 2 for corrosion or damage.
  • Inspect the loose engine ground wires.
  • Check for loose connectors at the ignition coils.
  • Check the spark plug of cylinder 2. A bad spark plug is one of the major causes of the misfire. If the spark plug is bad, replace it.
  • Inspect the coil pack wires for damage or corrosion.
  • Inspect and replace the coil pack wiring, coil packs or spark plug wiring if needed.
  • After all the above-given repairs and inspection, make a test drive. If the P0302 code returns, then inspect the fuel injector and fuel injector wiring for cylinder 2.
  • If your vehicle has a distributor cap and rotor button, then inspect them for excessive wear, cracks, corrosion, or any other damage.
  • Inspect the cylinder 2 compression system.
  • If your vehicle again triggers the P0302 code, an issue with the PCM is possible. Update the PCM software or replace it if needed.

Common P0302 Code Diagnostic Mistakes

  • Not properly inspecting all the parts
  • Replacing the unnecessary components
  • Inability to confirm the presence of the P0302 code
  • Clearing the code without first verifying the problem
  • Not clearing the PCM codes after fixing the codes
  • Replacing the spark plug or fuel injector without inspecting the wiring and connectors

Repair Costs for P0302 Code

The repair or fixing cost of the P0302 code varies according to labor cost, the vehicle model, and your area. To fix this code, you may need one or more of the following repairs:

PartsCost
Spark Plug replacement$60 to $260
Spark plug wiring repair$170 to $250
Fuel injector replacement$1400 to $2000
Ignition Coil replacement$220 to $650
Fuel pump replacement$250 to $1,090

FAQ Section

How much does it cost to fix a cylinder 2 misfire?

It is very hazardous to drive a vehicle with a bad cylinder or misfiring cylinder. If your cylinder is misfiring, then fix it as soon as possible to prevent yourself from an expensive repair. The average repair cost to fix a cylinder 2 misfire is from $90 to $1100, depending on the reason for the misfire.

How serious is the P0302 code?

The P0302 trouble code is considered serious. It makes the vehicle to drive difficult. This code indicates a misfire. It produces different drivability issues, such as stalling, poor acceleration, or poor fuel economy. You should fix the misfiring issues because it may lead to engine failure.

What repairs can fix the P0302 code?

  • Replacing the bad spark plug
  • If your cylinder is damaged, then replace it.
  • Replacing the damaged or corroded spark plug wires
  • Replacing the bad or damaged fuel injectors
  • Replacing or repairing the damaged coil pack wires
  • Replacing the throttle position sensor
  • Replacing the bad EGR valve
  • Replacing the bad O2 sensor
  • Replacing the burned valves
  • Replacing the bad MAF sensor
  • Repairing the fuel rail leaks
  • Repairing the vacuum leaks
  • Replacing or fixing the head gasket leaks
  • Replacing the bad crankshaft position sensor
  • Replacing the bad camshaft position sensor
  • Replacing the bad rotor button and distributor cap
  • Replacing the bad catalytic converter
  • Replacing the bad internal engine parts
  • Diagnosing and repairing any related trouble codes stored by the PCM
  • Replacing the bad fuel pump

Can low fuel cause a P0302 code?

Yes, insufficient fuel or low fuel pressure is one of the major causes of the P0302 code. When your engine has low fuel, there will be no proper supply of fuel to the engine cylinder, which will cause a misfire.

Can a bad Oxygen sensor cause misfire in the cylinder?

If your O2 sensor or MAF sensor is bad, it could give incorrect data to your engine’s computer, causing a misfire.

How do I know if I have a bad coil pack?

  1. Rough idling
  2. Louder noise from the engine than usual.
  3. Poor engine performance.
  4. A reduction in the engine speed
  5. Check engine light illumination
  6. Poor fuel economy
  7. Difficult to start the vehicle
  8. Jerking and vibrating acceleration
  9. Engine stalling

Can a bad catalytic converter cause a misfire?

A bad catalytic converter cause fuel within your engine cylinder to heat up to the point that it actually ignites. This ignition is what causes the misfiring sensation, which may badly damage your engine parts.  

Read More
  1. Symptoms of bad Fuel Pressure Sensor
  2. P0303 Symptoms and Causes
  3. P0304 Code Symptoms and Causes
  4. P0191 Code Symptoms and Causes

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