AutoCodes – GMC – P021B 2015 GMC Sierra

P021B 2015 GMC Sierra Code - Cylinder 8 Injection Timing

Quick Answer

The Engine Control Module (ECM) has the ability to learn injector timing performance. Common causes include Faulty Fuel Injector 8, Fuel Injector 8 harness is open or shorted, Fuel Injector 8 circuit poor electrical connection. 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: P021B 2015 GMC Sierra indicates Cylinder 8 Injection Timing.
Common causes: Common causes include Faulty Fuel Injector 8, Fuel Injector 8 harness is open or shorted, Fuel Injector 8 circuit poor electrical connection.
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 185

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 Mar 22, 2024

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code P021B 2015 GMC Sierra Description

The Engine Control Module (ECM) has the ability to learn injector timing performance. When the engine is at operating temperature, throttle closed and in deceleration fuel cut-off mode, the ECM will pulse each injector individually and measure the changes in rotational speed of the crankshaft using the input from the crankshaft position sensor. The ECM will run this diagnostic at one fuel rail pressure operating point for each injector. The ECM stores the injector timing value. The Diagnostic Trouble Code (DTC) will be set when the time to build up sufficient current to open the injector is below or above a predetermined threshold.

OBDII Code P021B 2015 GMC Sierra - Cylinder 8 Injection Timing - AutoCodes.com — P021B 2015 GMC Sierra Code - Cylinder 8 Injection Timing

What does this mean?

What are the Possible Causes of the DTC P021B 2015 GMC Sierra?

Faulty Fuel Injector 8
Fuel Injector 8 harness is open or shorted
Fuel Injector 8 circuit poor electrical connection
Faulty Engine Control Module (ECM)

How to Fix the DTC P021B 2015 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 is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P021B 2015 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 P021B 2015 GMC Sierra code?

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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 P021B 2015 GMC Sierra Code

1. What are the common symptoms of OBDII code P021B in a 2015 GMC Sierra related to Cylinder 8 Injection Timing?

The common symptoms include rough idling, decreased engine performance, misfires, and potentially poor fuel efficiency.

2. What are the possible causes of OBDII code P021B in a 2015 GMC Sierra?

Potential causes may include a faulty fuel injector, issues with the fuel injection system, electrical problems, or sensor malfunctions related to cylinder 8 injection timing.

3. How can I diagnose OBDII code P021B in a 2015 GMC Sierra at home?

You can use an OBDII scanner to retrieve the trouble code and further diagnose the issue. Checking the fuel injector on cylinder 8 for proper operation and inspecting related wiring and sensors can help pinpoint the problem.

4. Is it safe to continue driving a 2015 GMC Sierra with OBDII code P021B related to Cylinder 8 Injection Timing?

It is not recommended to drive the vehicle with this code unresolved, as it can lead to potential engine damage and worsen fuel efficiency over time.

5. Can I reset OBDII code P021B in a 2015 GMC Sierra myself?

While you can clear the code using an OBDII scanner, it is crucial to address the underlying issue causing the code to prevent it from reoccurring.

6. How much does it typically cost to repair OBDII code P021B in a 2015 GMC Sierra?

The cost of repair can vary depending on the exact cause of the code. It may involve replacing a faulty fuel injector, repairing wiring or sensors, or addressing issues with the fuel injection system.

7. Are there any preventive maintenance tips to avoid OBDII code P021B in a 2015 GMC Sierra?

Regularly servicing the fuel injection system, using quality fuel, and addressing any engine performance issues promptly can help prevent the occurrence of this trouble code.

8. Can a DIY enthusiast with basic automotive knowledge fix OBDII code P021B in a 2015 GMC Sierra?

Depending on the exact cause of the code, some DIY enthusiasts may be able to address the issue themselves, such as replacing a faulty fuel injector. However, complex electrical or sensor issues may require professional assistance.

9. How urgent is it to address OBDII code P021B in a 2015 GMC Sierra?

It is essential to address this code promptly to prevent potential damage to the engine and ensure optimal performance and fuel efficiency of the vehicle.

10. Will OBDII code P021B in a 2015 GMC Sierra cause the vehicle to fail an emissions test?

Yes, unresolved OBDII codes can cause a vehicle to fail an emissions test, so it's important to address and resolve the issue before undergoing any emissions testing.