AutoCodes – Subaru – P0305 Subaru

P0305 Subaru Code - Cylinder 5 Misfire Detected

Quick Answer

When a misfire occurs, engine speed will fluctuate. Common causes include Faulty spark plug 5, Clogged or faulty fuel injector 5, Faulty ignition coil 5. 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: P0305 Subaru indicates Cylinder 5 Misfire Detected.
Common causes: Common causes include Faulty spark plug 5, Clogged or faulty fuel injector 5, Faulty ignition coil 5.
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 13,311

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 Jun 14, 2020

Description
Step-by-Step Diagnostic Guide
Possible Causes
How To Fix
Tech Notes
Cost to Diagnose
FAQs
Comments
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Code P0305 Subaru Description

When a misfire occurs, engine speed will fluctuate. If the engine speed fluctuates enough to cause the Crankshaft Position (CKP) sensor signal to vary, the Engine Control Module (ECM) can determine that a misfire is occurring.

OBDII Code P0305 Subaru - Cylinder 5 Misfire Detected - AutoCodes.com — P0305 Subaru Code - Cylinder 5 Misfire Detected

What does this mean?

What are the Possible Causes of the DTC P0305 Subaru?

Faulty spark plug 5
Clogged or faulty fuel injector 5
Faulty ignition coil 5
Fuel injector 5 harness is open or shorted
Fuel injector 5 circuit poor electrical connection
Ignition coil 5 harness is open or shorted
Ignition coil 5 circuit poor electrical connection
Insufficient cylinder 5 compression
Incorrect fuel pressure
Intake air leak

How to Fix the DTC P0305 Subaru?

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 P0305 code means that the cylinder 5 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 5. If the problem persists more tests needs to be done to diagnose problem, see "Possible Causes"

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P0305 Subaru 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 P0305 Subaru Code

1. What are the common symptoms of OBDII code P0305 in a Subaru?

- Common symptoms include engine misfires, rough idle, loss of power, and potentially increased fuel consumption.

2. What are the possible causes of a cylinder 5 misfire in a Subaru?

- Possible causes include faulty spark plugs, a malfunctioning ignition coil, vacuum leaks, fuel delivery issues, or a problem with the engine's compression.

3. How can I diagnose the specific cause of a cylinder 5 misfire in my Subaru?

- You can diagnose the issue by performing a visual inspection of spark plugs and ignition components, conducting a compression test, checking for vacuum leaks, and using a scan tool to analyze live engine data.

4. Can driving with a cylinder 5 misfire cause further damage to my Subaru?

- Yes, driving with a misfire can potentially lead to damage to the catalytic converter, oxygen sensors, and other engine components over time.

5. Is it safe to continue driving my Subaru with OBDII code P0305?

- It is not recommended to drive the vehicle with a persistent misfire, as it can lead to more severe issues and may impact the overall performance and efficiency of the engine.

6. How much does it typically cost to repair a cylinder 5 misfire in a Subaru?

- The cost of repair can vary depending on the specific cause of the misfire, but it may range from a simple spark plug replacement to more complex repairs involving ignition components or engine tuning.

7. Can I attempt to fix a cylinder 5 misfire in my Subaru myself?

- DIY repairs are possible for some causes of a misfire, such as replacing spark plugs or ignition coils, but more complex issues may require professional diagnosis and repair.

8. Are there any preventive maintenance tips to avoid cylinder misfires in a Subaru?

- Regularly scheduled maintenance, including changing spark plugs at recommended intervals, ensuring proper fuel and air filter maintenance, and using quality fuel, can help prevent cylinder misfires.

9. Will resetting the OBDII code P0305 in my Subaru make the issue go away?

- Resetting the code may temporarily turn off the check engine light, but it will not fix the underlying issue causing the cylinder 5 misfire.

10. How long can I safely drive my Subaru with a cylinder 5 misfire before getting it repaired?

- It is best to address the issue as soon as possible to prevent further damage to the engine. Continuing to drive with a misfire can lead to more serious problems down the line.