AutoCodes – Honda – P0306 Honda

P0306 Honda Code - No. 1 Cylinder Misfire Detected6

Quick Answer

The crankshaft vibrates slightly when each cylinder fires. Common causes include Valve adjustment, Faulty spark plug #6, Faulty ignition coil #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 Honda indicates No. 1 Cylinder Misfire Detected6.
Common causes: Common causes include Valve adjustment, Faulty spark plug #6, Faulty ignition coil #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.

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Code Popularity 30,172

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Advanced (Pro) (3 / 3)

What is this?

Table of contents Created and updated by William Orellana on Aug 16, 2023

Description
Step-by-Step Diagnostic Guide
Possible Causes
How To Fix
Tech Notes
Cost to Diagnose
FAQs
Comments
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Code P0306 Honda Description

The crankshaft vibrates slightly when each cylinder fires. If a misfire occurs, the crankshaft rotation speed changes rapidly. The Powertrain Control Module (PCM) monitors the crankshaft rotation speed based on the output pulses from the Crankshaft Position (CKP) Sensor. By monitoring changes in the crankshaft rotation speed, the PCM counts the number of misfires and determines which cylinder is misfiring. If a misfire is detected, a Diagnostic Trouble Code (DTC) is stored.
There are two types of misfire detection: Type 1: When the number of misfires per 200 engine revolutions reaches the level that can damage the three-way catalyst (TWC), a DTC is stored and the MIL blinks. Type 2: When the number of misfires per 1,000 engine revolutions reaches the level that affects exhaust emissions but is not severe enough to immediately damage the catalyst, a DTC is stored, and the MIL comes on.

OBDII Code P0306 Honda - No. 1 Cylinder Misfire Detected6 - AutoCodes.com — P0306 Honda Code - No. 1 Cylinder Misfire Detected6

What does this mean?

What are the Possible Causes of the DTC P0306 Honda?

Valve adjustment
Faulty spark plug #6
Faulty ignition coil #6
Clogged or faulty fuel injector #6
Intake air leak
Insufficient cylinder #6 compression
Incorrect fuel pressure

How to Fix the DTC P0306 Honda?

Review the 'Possible Causes' above and visually examine the corresponding wiring harness and connectors. Check for damaged components and inspect connector pins for signs of being broken, bent, pushed out, or corroded.

What does this mean?

Code Tech Notes

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".

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P0306 Honda code, it typically requires 1.0 hour of labor. Rates vary by location, vehicle, and shop. Many shops charge between $80–$150 per hour; dealerships and metro areas may be higher, independents may be lower.

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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 Honda Code

1. What are common symptoms of OBDII code P0306 in a Honda?

Symptoms may include engine misfires, rough idle, loss of power, and potential increase in fuel consumption.

2. What are the possible causes of OBDII code P0306 indicating a No. 1 cylinder misfire in a Honda?

Common causes can include faulty spark plugs, ignition coils, fuel injectors, vacuum leaks, or issues with the engine's compression.

3. How can I diagnose the No. 1 cylinder misfire detected by OBDII code P0306 in my Honda?

Diagnosis typically involves checking the spark plug, ignition coil, fuel injector, and performing a compression test to pinpoint the issue.

4. Can driving with OBDII code P0306 on a Honda cause further damage?

Continued driving with a misfire can potentially damage the catalytic converter and other engine components, so it's advised to address the issue promptly.

5. Is it safe to continue driving my Honda with OBDII code P0306 appearing?

While you may be able to drive the vehicle for a short distance, it's recommended to have the issue fixed as soon as possible to prevent further damage.

6. How can I repair OBDII code P0306 related to a No. 1 cylinder misfire in my Honda?

Repairs may involve replacing faulty spark plugs, ignition coils, fuel injectors, or addressing any vacuum leaks in the system.

7. Can bad gasoline quality cause OBDII code P0306 in a Honda?

Poor quality gasoline with low octane levels or contaminants can contribute to engine misfires, potentially triggering code P0306.

8. Are there any maintenance tips to prevent OBDII code P0306 from recurring in my Honda?

Regularly changing spark plugs, maintaining the ignition system, using high-quality fuel, and addressing engine issues promptly can help prevent code P0306.

9. Will resetting the OBDII system clear code P0306 in my Honda?

While clearing the code may temporarily remove the warning light, the underlying issue causing the misfire will still need to be diagnosed and repaired.

10. How much can I expect to pay to fix OBDII code P0306 related to a No. 1 cylinder misfire in my Honda?

Repair costs can vary based on the specific issue causing the misfire, but it's advisable to consult a mechanic for an accurate diagnosis and cost estimate.