AutoCodes – Chevrolet – P0308 Chevrolet

P0308 Chevrolet 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 Chevrolet 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 33,625

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

What does this mean?

What are the Possible Causes of the DTC P0308 Chevrolet?

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 Chevrolet?

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 Chevrolet 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 Chevrolet code?

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

Need Help with the Code?

Get the P0308 Chevrolet code diagnosed by a professional: Find a repair shop in your area

Information for Specific Chevrolet Models

P0308 2014 Chevrolet Silverado — Cylinder 8 Misfire Detected
P0308 2015 Chevrolet Silverado — Cylinder 8 Misfire Detected
P0308 2016 Chevrolet Silverado — Cylinder 8 Misfire Detected
P0308 2017 Chevrolet Silverado — Cylinder 8 Misfire Detected
P0308 2018 Chevrolet Silverado — Cylinder 8 Misfire Detected

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 Chevrolet Code

1. What are the common symptoms of OBDII code P0308 (Cylinder 8 Misfire Detected) in a Chevrolet?

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

2. What are the possible causes of a Cylinder 8 misfire in a Chevrolet triggering code P0308?

- Possible causes include faulty spark plugs, ignition coils, fuel injectors, vacuum leaks, low compression, or issues with the engine's timing.

3. How can I diagnose the source of the Cylinder 8 misfire in my Chevrolet when experiencing code P0308?

- Diagnostic steps may include checking the spark plugs, ignition coils, fuel injectors, conducting a compression test, inspecting for vacuum leaks, and examining the engine's timing.

4. Can driving with a Cylinder 8 misfire, indicated by code P0308, cause further damage to my Chevrolet's engine?

- Yes, driving with a misfire can potentially cause damage to the catalytic converter, oxygen sensors, or other engine components due to unburned fuel entering the exhaust system.

5. Is it safe to continue driving my Chevrolet with OBDII code P0308 (Cylinder 8 Misfire Detected)?

- It is not recommended to drive the vehicle with a persistent misfire as it can lead to further damage and decreased engine performance.

6. How can I repair a Cylinder 8 misfire in my Chevrolet to resolve OBDII code P0308?

- Repair steps may involve replacing spark plugs, ignition coils, fuel injectors, fixing vacuum leaks, addressing compression issues, or adjusting the engine's timing.

7. Can a simple tune-up fix the Cylinder 8 misfire issue causing OBDII code P0308 in my Chevrolet?

- A tune-up including replacing spark plugs and ignition components may correct the misfire if they are the root cause of the issue.

8. What role does the engine's computer play in detecting and triggering code P0308 for a Cylinder 8 misfire in a Chevrolet?

- The engine control module (ECM) monitors engine performance and detects misfires, triggering a fault code like P0308 when it identifies a misfire in Cylinder 8.

9. Are there any maintenance tips to prevent Cylinder 8 misfires and OBDII code P0308 in a Chevrolet?

- Regular maintenance, such as timely spark plug and ignition coil replacements, using high-quality fuel, and addressing any engine performance issues promptly, can help prevent misfires.

10. How should I reset the OBDII code P0308 (Cylinder 8 Misfire Detected) after repairing the issue in my Chevrolet?

- After repairing the misfire issue, you can reset the fault code by using an OBDII scanner or disconnecting the vehicle's battery for a few minutes to clear the ECM's memory.