AutoCodes – GMC – P0302 2017 GMC Sierra

P0302 2017 GMC Sierra Code - Cylinder 2 Misfire Detected

Quick Answer

A misfiring cylinder causes slight variations in the rotational speed of the crankshaft. Common causes include Faulty Spark Plug #2, Clogged or faulty Fuel Injector #2, Faulty Ignition Coil #2. 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: P0302 2017 GMC Sierra indicates Cylinder 2 Misfire Detected.
Common causes: Common causes include Faulty Spark Plug #2, Clogged or faulty Fuel Injector #2, Faulty Ignition Coil #2.
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 298

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 Jul 21, 2022

Description
Step-by-Step Diagnostic Guide
Possible Causes
How To Fix
Tech Notes
Cost to Diagnose
FAQs
Comments
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Code P0302 2017 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 P0302 2017 GMC Sierra - Cylinder 2 Misfire Detected - AutoCodes.com — P0302 2017 GMC Sierra Code - Cylinder 2 Misfire Detected

What does this mean?

What are the Possible Causes of the DTC P0302 2017 GMC Sierra?

Faulty Spark Plug #2
Clogged or faulty Fuel Injector #2
Faulty Ignition Coil #2
Fuel Injector #2 harness is open or shorted
Fuel Injector #2 circuit poor electrical connection
Ignition Coil #2 harness is open or shorted
Ignition Coil #2 circuit poor electrical connection
Insufficient cylinder 2 compression
Incorrect fuel pressure
Intake air leak

How to Fix the DTC P0302 2017 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 P0302 code means that cylinder 2 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 2. 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 P0302
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 P0302 2017 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 P0302 2017 GMC Sierra 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 P0302 2017 GMC Sierra Code

1. What are the common symptoms of OBDII code P0302 in a 2017 GMC Sierra?

- Common symptoms include engine misfire, rough idling, loss of power, and increased fuel consumption.

2. What are the possible causes of a cylinder 2 misfire detected in a 2017 GMC Sierra?

- Causes may include faulty spark plugs, ignition coils, fuel injectors, vacuum leaks, low compression, or issues with the engine's sensors.

3. How can I diagnose the source of a cylinder 2 misfire in my 2017 GMC Sierra?

- Diagnose by checking spark plugs, ignition coils, fuel injectors, compression levels, vacuum leaks, and the engine control module for any fault codes.

4. Can driving with a cylinder 2 misfire in a 2017 GMC Sierra cause further damage?

- Yes, driving with a misfiring cylinder can potentially damage the catalytic converter, O2 sensors, and other engine components over time.

5. How can I repair OBDII code P0302 in my 2017 GMC Sierra?

- Repair options may include replacing spark plugs, ignition coils, fuel injectors, addressing vacuum leaks, performing a compression test, or resetting the engine control module.

6. Is it safe to continue driving my 2017 GMC Sierra with a cylinder 2 misfire detected?

- It is not recommended to drive with a misfiring cylinder as it can lead to further engine damage and potentially unsafe driving conditions.

7. Can bad gas quality cause a cylinder 2 misfire in a 2017 GMC Sierra?

- Yes, poor quality fuel or contaminated fuel can contribute to cylinder misfires in any vehicle, including a 2017 GMC Sierra.

8. How much does it typically cost to repair a cylinder 2 misfire in a 2017 GMC Sierra?

- The cost of repair can vary depending on the exact cause of the misfire, but it may range from a few hundred to over a thousand dollars for parts and labor.

9. Will resetting the check engine light make the cylinder 2 misfire in a 2017 GMC Sierra go away?

- Resetting the check engine light will not fix the underlying issue causing the misfire. It is essential to diagnose and repair the problem to resolve the code permanently.

10. Can extreme weather conditions contribute to a cylinder 2 misfire in a 2017 GMC Sierra?

- Yes, extreme weather conditions like extreme cold or heat can affect engine performance and potentially lead to misfires, especially if the vehicle's maintenance is not up to date.