AutoCodes – GMC – P0277 GMC

P0277 GMC Code - Cylinder 6 Injector Control Circuit High Voltage

Quick Answer

The Engine Control Module (ECM) supplies voltage to each Fuel Injector on the high control circuits. Common causes include Dirty Fuel Injector 6, Faulty Fuel Injector 6, Plugged Fuel Injector 6. 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: P0277 GMC indicates Cylinder 6 Injector Control Circuit High Voltage.
Common causes: Common causes include Dirty Fuel Injector 6, Faulty Fuel Injector 6, Plugged Fuel Injector 6.
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 374

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 23, 2024

Description
Possible Causes
How To Fix
Tech Notes
Cost to Diagnose
FAQs
Comments
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Code P0277 GMC Description

The Engine Control Module (ECM) supplies voltage to each Fuel Injector on the high control circuits. The ECM energizes each fuel injector by grounding the low control circuit of the fuel injector. The ECM monitors the status of the fuel injector circuits. When a fuel injector circuit condition is detected by the ECM, the affected fuel injector(s) is disabled. The Diagnostic Trouble Code (DTC) will be set when the ECM detects the fuel injector control circuit is shorted to voltage for greater than 2 s.

OBDII Code P0277 GMC - Cylinder 6 Injector Control Circuit High Voltage - AutoCodes.com — P0277 GMC Code - Cylinder 6 Injector Control Circuit High Voltage

What does this mean?

What are the Possible Causes of the DTC P0277 GMC?

Dirty Fuel Injector 6
Faulty Fuel Injector 6
Plugged Fuel Injector 6
Fuel injector 6 harness is open or shorted
Fuel injector 6 circuit poor electrical connection
Faulty Engine Control Module (ECM)

How to Fix the DTC P0277 GMC?

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

A clogged or partially clogged fuel injector can cause this code. Start by performing an injector flush before replacing the injector.

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P0277 GMC 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 P0277 GMC code?

Need more information on how to fix the P0277 GMC code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the P0277 GMC code diagnosed by a professional: Find a repair shop in your area

Information for Specific GMC Models

P0277 2014 GMC Sierra — Cylinder 6 Injector Control Circuit High Voltage
P0277 2015 GMC Sierra — Cylinder 6 Injector Control Circuit High Voltage
P0277 2016 GMC Sierra — Cylinder 6 Injector Control Circuit High Voltage
P0277 2017 GMC Sierra — Cylinder 6 Injector Control Circuit High Voltage
P0277 2018 GMC Sierra — Cylinder 6 Injector Control Circuit High Voltage

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 P0277 GMC Code

1. What does the OBDII code P0277 mean on a GMC?

P0277 indicates that the Engine Control Module (ECM) has detected high voltage in the injector control circuit for cylinder 6.

2. What are the common symptoms of the P0277 code?

Symptoms may include engine misfires, rough idling, reduced power, poor fuel economy, or the Check Engine Light illuminating.

3. What causes the P0277 code to appear?

Common causes include a faulty fuel injector, wiring issues like an open or short in the injector circuit, a malfunctioning ECM, or poor electrical connections.

4. Can I drive my GMC with a P0277 code?

Driving with a P0277 code is not recommended, as it can lead to engine performance problems, increased emissions, and potential damage to the engine or catalytic converter.

5. How is the P0277 code diagnosed?

A mechanic will check for stored codes, inspect the injector and its wiring for damage, test the voltage and resistance of the circuit, and potentially swap the injector with another cylinder to confirm the issue.

6. How do I fix a P0277 code on my GMC?

Repairs may include replacing the cylinder 6 injector, repairing or replacing damaged wiring or connectors, or reprogramming or replacing the ECM.

7. How much does it cost to fix the P0277 code?

Repair costs vary but typically range from $150 to $500 depending on whether the issue is with the injector, wiring, or ECM.

8. What happens if I ignore the P0277 code?

Ignoring the P0277 code can lead to worsening engine performance, higher emissions, and potential damage to other engine components over time.

9. Can a bad fuel injector cause permanent engine damage?

Yes, a faulty injector causing P0277 can lead to lean or rich conditions that, over time, may damage the engine or catalytic converter if not addressed.

10. Will clearing the code fix the P0277 issue?

Clearing the code without addressing the underlying problem will only temporarily remove the Check Engine Light; the code will return if the issue persists.