Engine-Codes.com
Engine-Codes – Generic – P0306

P0306 Code - Cylinder 6 Misfire Detected

Quick Answer

When the OBD-II system detects a misfire in cylinder 6, it means that the engine is not running smoothly, causing a lack of power, rough idling, and potential damage to the catalytic converter. Common causes include Faulty spark plug or ignition coil in cylinder 6, Clogged fuel injector affecting cylinder 6, Vacuum leak in the intake manifold near cylinder 6. Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

What it means
P0306 indicates Cylinder 6 Misfire Detected.
Common causes
Common causes include Faulty spark plug or ignition coil in cylinder 6, Clogged fuel injector affecting cylinder 6, Vacuum leak in the intake manifold near cylinder 6.
Severity
High - diagnose this code as soon as possible.
Can I drive?
Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.
What is this?
Table of contents Created and updated by William Orellana on Aug 18, 2024
💬 Need more help? Ask Auto Expert for instant answers — it's free!
AutoCodes App

Fix Your Car Smarter

Try the New AutoCodes App!

Get complete OBDII diagnostics, repair solutions, and cost estimates, plus AI chat support on demand.

AutoCodes App on Google Play

Code P0306 Description

When the OBD-II system detects a misfire in cylinder 6, it means that the engine is not running smoothly, causing a lack of power, rough idling, and potential damage to the catalytic converter. A misfire occurs when the fuel-air mixture in the cylinder does not ignite at the proper time or at all. This can be caused by issues such as a faulty ignition system, fuel delivery problems, vacuum leaks, or engine mechanical problems. Ignoring this issue can lead to decreased fuel efficiency, increased emissions, and potential damage to other engine components.

OBDII Code P0306 - Cylinder 6 Misfire Detected
P0306 Code - Cylinder 6 Misfire Detected

Common Causes of P0306

  1. Faulty spark plug or ignition coil in cylinder 6.
  2. Clogged fuel injector affecting cylinder 6.
  3. Vacuum leak in the intake manifold near cylinder 6.
  4. Low compression in cylinder 6 due to a leaking head gasket or worn piston rings.
  5. Electrical issues in the ignition system such as a faulty wiring harness or ignition control module.

Symptoms of P0306

  1. Rough idling or vibrations felt in the vehicle.
  2. Loss of power or acceleration.
  3. Engine misfiring or stuttering during acceleration.
  4. Increased fuel consumption.
  5. Check Engine Light illuminated on the dashboard.

How to Fix P0306

  1. Diagnose the specific cause of the misfire by performing a compression test, checking spark plugs, ignition coils, fuel injectors, and conducting a vacuum leak test.
  2. Replace the faulty spark plug or ignition coil in cylinder 6.
  3. Clean or replace clogged fuel injector for cylinder 6.
  4. Repair any vacuum leaks near cylinder 6.
  5. Address any underlying engine mechanical issues causing the misfire in cylinder 6.

Cost to Fix P0306

The repair costs for addressing a cylinder 6 misfire can vary depending on the specific cause of the issue and the labor rates in your area. On average, the cost of parts such as spark plugs, ignition coils, or fuel injectors can range from $50 to $200 per component. Labor costs can range from $100 to $300, depending on the complexity of the repair and the shop's hourly rate. Overall, you can expect to pay anywhere from $150 to $500 for resolving a cylinder 6 misfire, but it's always recommended to get a detailed quote from a reputable auto repair shop before proceeding with the repair.

What does this mean?

Tech Notes for P0306

The P0306 code means that cylinder 6 is misfiring or is randomly misfiring. Start by checking for intake leaks and if no leaks are found the next step is to replace the spark plugs on cylinder 6. If the problem persists more tests need to be done to diagnose the problem, see "Possible Causes".

P0014 / P0306 2002 Trailblazer








User Submitted Video

Need more information about the P0306 code?

Need more information on how to fix the P0306 code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the P0306 code diagnosed by a professional: Find a repair shop in your area

Code P0306 Information for Specific Makes

About the author: William Orellana is a Master Mechanic and Mechanical Engineer with over 30 years of experience diagnosing and repairing vehicles. Learn more about his background.

Frequently Asked Questions about P0306 Code

1. What are common symptoms of OBDII code P0306 (Cylinder 6 Misfire Detected)?

Symptoms may include engine misfiring, rough idling, loss of power, decreased fuel efficiency, and potential engine vibrations.

2. What are the possible causes of a Cylinder 6 misfire detected error code?

Common causes may include faulty spark plugs, ignition coils, fuel injectors, vacuum leaks, low compression in the cylinder, or issues with the engine control module.

3. How can I diagnose the source of the Cylinder 6 misfire on my vehicle?

Diagnosis typically involves checking spark plugs, ignition coils, fuel injectors, compression levels, vacuum leaks, and the engine control module using diagnostic tools and a systematic approach.

4. Can a dirty or clogged fuel injector cause a Cylinder 6 misfire?

Yes, a dirty or clogged fuel injector can disrupt the proper fuel flow to Cylinder 6, leading to a misfire and triggering the P0306 error code.

5. Is it safe to continue driving with an OBDII code P0306 (Cylinder 6 Misfire Detected) present?

Continuing to drive with a misfire can potentially cause damage to the catalytic converter or other engine components. It is recommended to address the issue promptly to prevent further damage.

6. How can I repair a Cylinder 6 misfire issue myself?

DIY repair steps may include replacing spark plugs, ignition coils, or fuel injectors, checking for vacuum leaks, performing a compression test, and clearing the error code using an OBDII scanner.

7. Can a bad ignition coil cause a Cylinder 6 misfire?

Yes, a faulty ignition coil can lead to a lack of spark in Cylinder 6, causing a misfire and triggering the P0306 error code.

8. What role does the engine control module (ECM) play in a Cylinder 6 misfire situation?

The ECM monitors engine performance and can identify misfires in specific cylinders, such as Cylinder 6, by analyzing data from sensors. A malfunctioning ECM can also contribute to misfire issues.

9. Are there any preventive maintenance measures to avoid a Cylinder 6 misfire in the future?

Regularly servicing and replacing spark plugs, ignition coils, and fuel injectors, as well as addressing any engine performance issues promptly, can help prevent Cylinder 6 misfires and related error codes.

10. Can extreme weather conditions impact the likelihood of a Cylinder 6 misfire?

Extreme temperatures, humidity, or environmental factors can affect engine performance and potentially lead to misfires, including those in Cylinder 6. Maintaining proper engine health and monitoring for symptoms is crucial in such conditions.

Discuss the causes and fixes for P0306 OBDII Code

Submit a New Comment

  • Engine light on p0306 code. Switch coil replace spark plug replace injecter. Ck ck. Wiring ck. Comprestion all ck ok. Light keep comes on same code??

    Reply to Comment

  • If the plug is wet, you might have a head gasket leaking coolant into the cylinder. Please check your coolant level ASAP.

    Reply to Comment

  • Replaced plugs, wires, rotor, cap, & distributer. Still showing same code! whatsup!

    Reply to Comment

  • What make, model and year is your vehicle? You should perform a compression test, the engine may have a blown head gasket.

    Reply to Comment