AutoCodes – Chevrolet – P0308 2018 Chevrolet Silverado

P0308 2018 Chevrolet Silverado Code - Cylinder 8 Misfire Detected

Quick Answer

A misfiring cylinder causes slight variations in the rotational speed of the crankshaft. Common causes include Faulty spark plug 8, Clogged or faulty fuel injector 8, Faulty ignition coil 8. 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: P0308 2018 Chevrolet Silverado indicates Cylinder 8 Misfire Detected.
Common causes: Common causes include Faulty spark plug 8, Clogged or faulty fuel injector 8, Faulty ignition coil 8.
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 547

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Advanced (Pro) (3 / 3)

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Table of contents Created and updated by William Orellana on Aug 09, 2022

Description
Possible Causes
How To Fix
Tech Notes
Cost to Diagnose
FAQs
Comments
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Code P0308 2018 Chevrolet Silverado 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 P0308 2018 Chevrolet Silverado - Cylinder 8 Misfire Detected - AutoCodes.com — P0308 2018 Chevrolet Silverado Code - Cylinder 8 Misfire Detected

What does this mean?

What are the Possible Causes of the DTC P0308 2018 Chevrolet Silverado?

Faulty spark plug 8
Clogged or faulty fuel injector 8
Faulty ignition coil 8
Fuel injector 8 harness is open or shorted
Fuel injector 8 circuit poor electrical connection
Ignition coil 8 harness is open or shorted
Ignition coil 8 circuit poor electrical connection
Insufficient cylinder 8 compression
Incorrect fuel pressure
Intake air leak

How to Fix the DTC P0308 2018 Chevrolet Silverado?

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 P0308 code means that cylinder 8 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 8. 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 P0308
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 P0308 2018 Chevrolet Silverado 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 P0308 2018 Chevrolet Silverado code?

Need more information on how to fix the P0308 2018 Chevrolet Silverado code? Get Access to Factory Service Manuals

Need Help with the Code?

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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 P0308 2018 Chevrolet Silverado Code

1. What are the common symptoms of OBDII code P0308 on a 2018 Chevrolet Silverado?

- Common symptoms of code P0308, indicating a cylinder 8 misfire on a 2018 Chevrolet Silverado, include rough idling, loss of power, engine stalling, and increased fuel consumption.

2. What are the possible causes of a cylinder 8 misfire in a 2018 Chevrolet Silverado?

- The misfire in cylinder 8 of a 2018 Chevrolet Silverado can be caused by issues such as faulty spark plugs, ignition coils, fuel injectors, vacuum leaks, or a problem with the engine's compression.

3. How can I diagnose the cause of the cylinder 8 misfire in my 2018 Chevrolet Silverado?

- To diagnose the cause of the cylinder 8 misfire, you can start by checking the spark plugs, ignition coils, and fuel injectors in that cylinder. Performing a compression test and inspecting for vacuum leaks can also help pinpoint the issue.

4. Is it safe to continue driving my 2018 Chevrolet Silverado with OBDII code P0308?

- It is not recommended to drive your 2018 Chevrolet Silverado with a cylinder 8 misfire (code P0308) as it can lead to further damage to the engine and other components. Immediate attention and repair are advised.

5. How can I repair a cylinder 8 misfire in my 2018 Chevrolet Silverado?

- Repairing a cylinder 8 misfire in a 2018 Chevrolet Silverado may involve replacing faulty spark plugs, ignition coils, or fuel injectors, as well as addressing any vacuum leaks or compression issues. It's best to consult a professional mechanic for a thorough diagnosis and repair.

6. Can a dirty or clogged fuel injector cause OBDII code P0308 on a 2018 Chevrolet Silverado?

- Yes, a dirty or clogged fuel injector in cylinder 8 can cause a misfire and trigger OBDII code P0308 on a 2018 Chevrolet Silverado. Cleaning or replacing the fuel injector may be necessary to resolve the issue.

7. Will driving with a cylinder 8 misfire damage the catalytic converter in my 2018 Chevrolet Silverado?

- Driving with a cylinder 8 misfire in your 2018 Chevrolet Silverado can potentially lead to damage to the catalytic converter due to unburned fuel entering the exhaust system. Prompt repair is recommended to prevent further issues.

8. How important is it to address OBDII code P0308 promptly in a 2018 Chevrolet Silverado?

- It is crucial to address OBDII code P0308 promptly in a 2018 Chevrolet Silverado to prevent potential engine damage, decreased fuel efficiency, and drivability issues. Ignoring the misfire can lead to more costly repairs down the line.

9. Can a faulty ignition coil cause a cylinder 8 misfire in a 2018 Chevrolet Silverado?

- Yes, a faulty ignition coil in cylinder 8 can cause a misfire and trigger OBDII code P0308 on a 2018 Chevrolet Silverado. Replacing the faulty ignition coil is a common repair for this issue.

10. Are there any preventative maintenance tips to avoid OBDII code P0308 in a 2018 Chevrolet Silverado?

- Regularly scheduled maintenance, such as changing spark plugs, inspecting ignition components, and ensuring proper fuel system function, can help prevent cylinder misfires and OBDII code P0308 in a 2018 Chevrolet Silverado.