AutoCodes – GMC – P021A 2017 GMC Sierra

P021A 2017 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 2017 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 192

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 Mar 22, 2024

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code P021A 2017 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 2017 GMC Sierra - Cylinder 7 Injection Timing - AutoCodes.com — P021A 2017 GMC Sierra Code - Cylinder 7 Injection Timing

What does this mean?

What are the Possible Causes of the DTC P021A 2017 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 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 is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P021A 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 P021A 2017 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 2017 GMC Sierra Code

What does the OBDII code P021A mean on a 2017 GMC Sierra?

P021A refers to "Cylinder 7 Injection Timing," indicating an issue with the timing of fuel injection for cylinder 7, which could impact performance or emissions.

What are the common symptoms of code P021A in a 2017 GMC Sierra?

Symptoms may include rough idling, reduced fuel efficiency, engine misfires, poor acceleration, or the check engine light being illuminated.

What causes the P021A code to appear on a 2017 GMC Sierra?

Common causes include a faulty fuel injector, wiring issues related to the injector, a failing engine control module (ECM), or low fuel pressure.

Can I drive my 2017 GMC Sierra with a P021A code?

Driving with this code is not recommended as it can cause further engine damage, reduced performance, or increased emissions.

How is the P021A code diagnosed?

A mechanic will use a scan tool to confirm the code, inspect the fuel injector and wiring for cylinder 7, and test the fuel pressure and ECM functionality.

How do you fix the P021A code on a 2017 GMC Sierra?

Repairs may involve replacing the cylinder 7 fuel injector, fixing damaged wiring or connectors, or updating or replacing the ECM if needed.

What tools are needed to diagnose a P021A code?

A professional-grade OBDII scanner, a multimeter for electrical testing, and possibly a fuel pressure gauge are typically required for diagnosis.

How much does it cost to fix a P021A code on a 2017 GMC Sierra?

Repair costs can range from $150 to $500 or more, depending on whether the issue involves replacing a fuel injector, repairing wiring, or addressing ECM problems.

Can a clogged fuel filter cause a P021A code?

While a clogged fuel filter can affect overall fuel pressure, it is less likely to specifically trigger a P021A code. However, low fuel pressure should still be checked.

How can I prevent a P021A code from occurring in the future?

Regular maintenance, including fuel system cleaning, replacing fuel filters, and inspecting wiring, can help prevent injection timing issues like P021A.