AutoCodes – GMC – P021A 2016 GMC Sierra

P021A 2016 GMC Sierra Code - Cylinder 7 Injection Timing

Quick Answer

The Engine Control Module (ECM) has the ability to learn injector timing performance. Common causes include Faulty Fuel Injector 7, Fuel Injector 7 harness is open or shorted, Fuel Injector 7 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: P021A 2016 GMC Sierra indicates Cylinder 7 Injection Timing.
Common causes: Common causes include Faulty Fuel Injector 7, Fuel Injector 7 harness is open or shorted, Fuel Injector 7 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 157

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 P021A 2016 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 P021A 2016 GMC Sierra - Cylinder 7 Injection Timing - AutoCodes.com — P021A 2016 GMC Sierra Code - Cylinder 7 Injection Timing

What does this mean?

What are the Possible Causes of the DTC P021A 2016 GMC Sierra?

Faulty Fuel Injector 7
Fuel Injector 7 harness is open or shorted
Fuel Injector 7 circuit poor electrical connection
Faulty Engine Control Module (ECM)

How to Fix the DTC P021A 2016 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 P021A 2016 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 P021A 2016 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 P021A 2016 GMC Sierra Code

1. What does OBDII code P021A mean for a 2016 GMC Sierra?

P021A indicates an issue with the injection timing for cylinder 7, which may affect the engine’s performance.

2. What are common symptoms of code P021A on a 2016 GMC Sierra?

Symptoms include rough idling, decreased fuel efficiency, misfires, loss of power, or difficulty accelerating.

3. What causes code P021A in a 2016 GMC Sierra?

Common causes include a faulty fuel injector, wiring issues, a malfunctioning injector timing control module, or low fuel pressure.

4. Can driving with P021A damage my 2016 GMC Sierra?

Yes, prolonged driving with this code can lead to engine damage or reduced performance due to improper fuel injection timing.

5. How is code P021A diagnosed on a 2016 GMC Sierra?

Technicians use a diagnostic scanner to retrieve the code, inspect the fuel injector for cylinder 7, check wiring and connections, and test fuel pressure.

6. How do I fix code P021A on a 2016 GMC Sierra?

Repairs may include replacing the fuel injector for cylinder 7, repairing damaged wiring, or addressing issues with the injector timing control module.

7. Can poor fuel quality cause code P021A?

Yes, contaminated or low-quality fuel can affect injector performance and lead to this code.

8. Is replacing the fuel injector always necessary for code P021A?

Not always; the issue could be related to wiring, connections, or the timing control module instead of the injector itself.

9. How much does it cost to repair code P021A on a 2016 GMC Sierra?

Repair costs vary but generally range from $200 to $800 depending on whether the fuel injector, wiring, or other components need replacement.

10. Can a DIYer fix code P021A on a 2016 GMC Sierra?

If you have experience with fuel systems and diagnostic tools, you may be able to handle simple repairs like checking wiring or replacing the injector. Complex issues may require professional help.