AutoCodes – GMC – P0305 2014 GMC Sierra

P0305 2014 GMC Sierra Code - Cylinder 5 Misfire Detected

Quick Answer

A misfiring cylinder causes slight variations in the rotational speed of the crankshaft. 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 2014 GMC Sierra 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.

Save to My Repairs Step-by-Step Diagnostic Guide My Repairs

AI answers can be wrong. Verify repairs with testing. Open full chat

Code Popularity 376

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 09, 2022

Description
Step-by-Step Diagnostic Guide
Possible Causes
How To Fix
Tech Notes
Cost to Diagnose
FAQs
Comments
Add Comment

💬 Need more help? Ask Coddy for instant answers — it's free!

Code P0305 2014 GMC Sierra Description

A misfiring cylinder causes slight variations in the rotational speed of the crankshaft. The Engine Control Module (ECM) can detect these variations by closely monitoring the crankshaft position sensor signal. The signals of the camshaft position sensors are used to determine which cylinder is misfiring. If the ECM detects a misfire rate sufficient to cause emission levels to exceed mandated standards, the Diagnostic Trouble Code (DTC) will be set. Under certain driving conditions, a misfire rate can be high enough to cause the catalytic converter to overheat, damaging the converter. The Malfunction Indicator Lamp (MIL) flashes when the converter is overheating, damaging conditions are present, and the DTC is set. The DTC will be set when the ECM detects a crankshaft rotation speed variation indicating a single-cylinder misfire rate sufficient to cause emissions levels to exceed mandated standards.

OBDII Code P0305 2014 GMC Sierra - Cylinder 5 Misfire Detected - AutoCodes.com — P0305 2014 GMC Sierra Code - Cylinder 5 Misfire Detected

What does this mean?

What are the Possible Causes of the DTC P0305 2014 GMC Sierra?

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 2014 GMC Sierra?

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 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 need to be done to diagnose the problem, see "Possible Causes".

There is a Factory Service Bulletins for All 2000-2020 Chevrolet Models:
2000-2020 Chevrolet Factory Service Bulletin OBDII Code P0305
This Factory Service Bulletin explains how this condition may be caused by significant carbon build-up on the intake and/or exhaust valves due to fuel contamination or incomplete burning of the fuel.

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P0305 2014 GMC Sierra 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.

Need more information about the P0305 2014 GMC Sierra code?

Need more information on how to fix the P0305 2014 GMC Sierra code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the P0305 2014 GMC Sierra code diagnosed by a professional: Find a repair shop in your area

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 2014 GMC Sierra Code

1. What are the common symptoms of OBDII code P0305 in a 2014 GMC Sierra indicating a cylinder 5 misfire?

- Common symptoms include rough idling, engine vibration, loss of power, and potential hesitation during acceleration.

2. What are some possible causes of a cylinder 5 misfire detected in a 2014 GMC Sierra with code P0305?

- Causes can range from faulty spark plugs or ignition coils, vacuum leaks, fuel delivery issues, to a malfunctioning fuel injector or even internal engine problems.

3. How can I diagnose the specific cause of the cylinder 5 misfire in my 2014 GMC Sierra triggering OBDII code P0305?

- Diagnostic steps may involve checking spark plugs, ignition coils, fuel injectors, vacuum lines, and performing a compression test to pinpoint the exact issue.

4. What are the recommended repair tips for resolving a cylinder 5 misfire detected in a 2014 GMC Sierra with code P0305?

- Repair tips may include replacing faulty spark plugs, ignition coils, or fuel injectors, fixing vacuum leaks, cleaning or replacing the EGR valve, and ensuring proper fuel delivery.

5. Can driving with OBDII code P0305 indicating a cylinder 5 misfire in a 2014 GMC Sierra cause further damage to the vehicle?

- Continued driving with a misfire can potentially damage the catalytic converter, oxygen sensors, or even the engine itself, so it's advisable to address the issue promptly.

6. Is it safe to clear the OBDII code P0305 related to a cylinder 5 misfire in a 2014 GMC Sierra without fixing the underlying problem?

- Clearing the code without fixing the root cause can temporarily remove the warning light, but the issue will likely reoccur and may lead to more severe problems over time.

7. How much does it typically cost to repair a cylinder 5 misfire detected in a 2014 GMC Sierra triggering OBDII code P0305?

- 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 diagnostics.

8. Are there any preventive maintenance measures to help avoid cylinder misfires in a 2014 GMC Sierra and prevent OBDII code P0305 from appearing?

- Regularly scheduled maintenance such as changing spark plugs, inspecting ignition components, using quality fuel, and addressing any engine issues promptly can help prevent cylinder misfires.

9. Can extreme weather conditions or poor fuel quality contribute to triggering OBDII code P0305 related to a cylinder 5 misfire in a 2014 GMC Sierra?

- Yes, extreme weather conditions affecting engine performance or poor-quality fuel can potentially contribute to misfires, so it's important to consider these factors when diagnosing the issue.

10. How long can I safely drive my 2014 GMC Sierra with OBDII code P0305 indicating a cylinder 5 misfire before getting it repaired?

- It's recommended to address the misfire issue promptly to prevent further damage, so it's best not to drive the vehicle extensively with a persistent cylinder misfire detected.