What is code po301 on Dodge Dart?
P0301 is the diagnostic trouble code that signals a misfire in cylinder 1 on many Dodge Dart engines. When the engine control module detects irregular combustion in the first cylinder, it lights the check engine light and stores P0301.
In this article, we break down what the code means for Dodge Dart owners, common causes, how to diagnose it, and the typical repairs you might encounter. The goal is to help you understand the issue and decide on the right next steps.
What P0301 Indicates for the Dodge Dart
Common causes
The following are the most frequent reasons a Dodge Dart might register P0301:
- Worn or fouled spark plug in cylinder 1
- Faulty ignition coil or damaged spark plug boot on cylinder 1
- Dirty, clogged, or leaking fuel injector for cylinder 1
- Low fuel pressure or failing fuel pump affecting the cylinder 1 injector supply
- Compression loss in cylinder 1 due to valve, ring, or head gasket issues
- Damaged or loose wiring/connectors to the ignition coil or injector
- PCV or other air-control issues leading to lean misfire conditions
Note: P0301 specifically points to cylinder 1, but misfires can sometimes appear as P0300 (random/multiple cylinders) if multiple cylinders are affected.
How to diagnose P0301 on a Dodge Dart
Diagnosing P0301 involves verifying the misfire and isolating the cause. The steps below outline a practical approach, though some diagnostics may require specialized tools or service information for your exact Dart model and engine.
- Connect an OBD-II scanner to confirm P0301 and review freeze-frame data, misfire counters, and other related codes.
- Inspect the spark plug on cylinder 1 for wear, fouling, or damage; replace if needed.
- Test or swap the ignition coil or coil pack from cylinder 1 with another cylinder to see if the misfire follows the coil.
- Check the wiring and connectors to the cylinder 1 coil and injector for corrosion, damage, or loose pins.
- Inspect the fuel injector for cylinder 1: listen for operation, check resistance, perform a flow test, or swap with another injector.
- Examine the intake vacuum and gasket around cylinder 1 for leaks; use a spray test or smoke method to detect leaks.
- Measure fuel pressure to ensure the engine is receiving adequate fuel; validate fuel pump performance and pressure regulator operation.
- Perform a compression test or cylinder leak-down test on cylinder 1 to assess mechanical health of the piston, rings, valves, and.head gasket.
- Clear codes and road-test the vehicle to verify whether the misfire reoccurs under load, idle, or specific RPM ranges.
If the misfire persists after these checks, deeper issues such as timing concerns or internal engine damage may be involved, and a professional evaluation is advised.
Repairs commonly associated with P0301
Based on the diagnosed cause, typical repairs include:
- Replacing the spark plug and/or ignition coil for cylinder 1
- Cleaning or replacing the cylinder 1 fuel injector
- Repairing vacuum leaks or replacing intake manifold gaskets and PCV components
- Repairing or securing wiring and connectors to the coil or injector
- Addressing fuel system issues such as a failing fuel pump or pressure regulator
- Carrying out mechanical repairs if compression issues are found (valve seating, head gasket, etc.)
After repairs, clear the codes and perform a test drive to confirm the issue is resolved and that no new codes appear.
What this means for Dodge Dart ownership
A P0301 code should be treated promptly to prevent potential catalytic converter damage from continued misfires and to restore engine performance and fuel efficiency. Start with the simplest, most common fixes (spark plug and ignition coil) and proceed to fuel, vacuum, and mechanical checks as needed. If you’re unsure or the problem persists after basic steps, seek a qualified technician familiar with Dodge Dart engines and the specific model year.
Summary
P0301 on a Dodge Dart signals a cylinder 1 misfire detected by the engine control module. Common causes include a faulty spark plug, ignition coil, injector, vacuum leak, fuel pressure issue, or mechanical problems in cylinder 1. A systematic diagnostic approach—checking ignition components, fuel delivery, vacuum integrity, wiring, and compression—helps identify the root cause. Timely diagnosis and appropriate repairs can restore smooth running and protect the exhaust and catalytic system.
What is the most common cause of cylinder 1 misfire?
There are a plethora of potential causes, but some are more likely than others. The following are the most common: Distributor failure. Worn-out, dirty or faulty spark plugs.
How do I fix code PO301?
To fix P0301, you must first diagnose the cause, which is a misfire in cylinder 1, and then address the problem, likely by replacing faulty components like spark plugs, ignition coils, or fuel injectors. Other potential fixes include repairing wiring issues, fixing vacuum leaks, or addressing low compression in that cylinder.
This video provides a step-by-step guide on diagnosing and fixing a P0301 code: 47sCaristaYouTube · Jun 18, 2025
Step 1: Troubleshoot and replace parts
- Spark Plugs: Inspect the spark plug in cylinder 1. If it's worn, fouled, or has incorrect spacing, replace it. You may want to check and replace all spark plugs at the same time.
- Ignition Coils: Swap the ignition coil from cylinder 1 with a coil from another cylinder (e.g., cylinder 3). If the misfire code changes to match the new cylinder (e.g., P0303), the coil is the problem and needs to be replaced.
- Fuel Injectors: If the spark and coil are good, check the fuel injector. You can test it by swapping it with another one. If the misfire follows the injector, replace it. Also, check the wiring to the injector for damage or corrosion.
- Wiring: Inspect all wiring and connectors related to cylinder 1's ignition and fuel systems for damage, corrosion, or loose connections.
Step 2: Address mechanical or system issues
- Vacuum Leaks: Check for vacuum leaks, especially around the intake manifold, as this can cause misfires.
- Compression Test: If the previous steps don't resolve the issue, perform a compression test on cylinder 1. Low compression can be caused by issues with piston rings or valves and will require more involved engine repair.
- Sensor Issues: Problems with sensors like the crankshaft, camshaft, or O2 sensors can sometimes trigger misfire codes.
Step 3: Clear the code and test
- After performing any fixes, use an OBD-II scanner to clear the P0301 code.
- Drive the vehicle to see if the code returns. If it does, repeat the diagnostic process, starting with the most likely culprits like the spark plug, coil, or injector.
This video demonstrates how to clear an engine code after a repair using a car scanner: 46snondaYouTube · Oct 22, 2020
What is the code P0301 on a Dodge Dart?
A P0301 code on a Dodge Dart means cylinder 1 is misfiring, which is often caused by a faulty spark plug, ignition coil, or fuel injector. Symptoms include a rough idle, lack of power, and the check engine light. Diagnosis involves checking these ignition and fuel components, and a more advanced check for mechanical issues like low compression can be performed if the basic components are fine.
This video shows how to check the spark plug and ignition coil for a Dodge Dart: 57snondaYouTube · May 6, 2021
Common causes
- Ignition system: A bad spark plug or a failing ignition coil are very common causes for this code.
- Fuel system: A clogged or faulty fuel injector for cylinder 1 can prevent it from getting the proper amount of fuel.
- Engine compression: A more serious cause is low compression in cylinder 1, which could be due to a burned valve or a leaky head gasket.
- Wiring: Damaged or corroded wiring and connectors to the coil or injector can disrupt the signal.
Symptoms
- Check engine light is illuminated
- Rough idling or sputtering
- Difficulty starting
- Lack of power, especially when accelerating
- Decreased fuel economy
- The engine may stall when coming to a stop
You can watch this video to learn what a P0301 code means and the potential causes: 53sFIXDYouTube · Mar 12, 2019
Diagnosis and troubleshooting
- Check the basics: Start with the simplest potential causes. Inspect the spark plug and ignition coil for cylinder 1 for any signs of wear, fouling, or damage.
- Swap components: A simple test for the ignition coil is to swap it with a coil from another cylinder (e.g., cylinder 2). If the misfire code changes to P0302, the coil is faulty and needs replacement.
- Inspect the fuel injector: If the coil and spark plug are good, check the fuel injector for cylinder 1. Make sure its wiring is secure and not damaged. A mechanic can test the injector for proper operation.
- Perform a compression test: If the problem is still not found, a compression test can reveal if there is a mechanical issue with the cylinder itself.
- Scan for other codes: Use an OBD-II scanner to check for any other related codes, which can provide more clues about the problem.
Why is my car still misfiring after I change the spark plugs and ignition coil?
Your car may still be misfiring after changing the spark plugs and ignition coils because the problem lies with other components such as the fuel injectors, vacuum leaks, worn spark plug wires, or low engine compression. Other potential causes include issues with the fuel delivery system, airflow to the engine, or ignition timing.
This video explains the possible reasons why your car is still misfiring after changing the spark plugs and ignition coils: 59sFixITYouTube · Oct 3, 2024
Other potential causes
- Fuel system issues: A dirty or malfunctioning fuel injector, a clogged fuel filter, or low fuel pressure can lead to improper fuel delivery.
- Vacuum leaks: Leaks in the intake manifold or other vacuum lines can cause an imbalance in the air-fuel mixture.
- Spark plug wires: Even with new coils, old or damaged wires can prevent a strong spark from reaching the plugs.
- Low compression: This can be caused by issues like a worn piston ring, a leaky valve, or a blown head gasket, all of which prevent the cylinder from compressing the air-fuel mixture effectively.
- Incorrect timing: If the ignition timing is off, the spark plug won't fire at the right moment for efficient combustion.
- Faulty new parts: It's possible that one of the "new" parts is defective, so it's worth swapping the new coil with one from a cylinder that isn't misfiring to see if the problem follows the coil.
- Wiring and connector issues: Corroded, damaged, or loose connectors to the coils or fuel injectors can cause misfires.
- Carbon buildup: Excessive carbon deposits on the intake valves can prevent them from sealing properly, especially in direct-injection engines.
