AutoCodes – GMC – P124B 2017 GMC Sierra

P124B 2017 GMC Sierra Code - Injector 4 Positive Voltage Control Circuit Shorted to Control Circuit

Quick Answer

The Engine Control Module (ECM) supplies voltage to each fuel injector on the injector high voltage supply circuits. Common causes include Faulty Fuel Injector 4, Fuel Injector 4 harness is open or shorted, Fuel Injector 4 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: P124B 2017 GMC Sierra indicates Injector 4 Positive Voltage Control Circuit Shorted to Control Circuit.
Common causes: Common causes include Faulty Fuel Injector 4, Fuel Injector 4 harness is open or shorted, Fuel Injector 4 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 1,135

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 Aug 12, 2022

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code P124B 2017 GMC Sierra Description

The Engine Control Module (ECM) supplies voltage to each fuel injector on the injector high voltage supply circuits. The ECM energizes each fuel injector by grounding the high voltage control circuit of the fuel injector. The ECM monitors the status of the injector high voltage supply circuits and the fuel injector high voltage control 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 if the ECM detects the injector high control circuit is shorted to the low control circuit for greater than 2 s.

OBDII Code P124B 2017 GMC Sierra - Injector 4 Positive Voltage Control Circuit Shorted to Control Circuit - AutoCodes.com — P124B 2017 GMC Sierra Code - Injector 4 Positive Voltage Control Circuit Shorted to Control Circuit

What does this mean?

What are the Possible Causes of the DTC P124B 2017 GMC Sierra?

Faulty Fuel Injector 4
Fuel Injector 4 harness is open or shorted
Fuel Injector 4 circuit poor electrical connection
Faulty Engine Control Module (ECM)

How to Fix the DTC P124B 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 P124B 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 P124B 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 P124B 2017 GMC Sierra Code

1. What does the OBDII code P124B mean on a 2017 GMC Sierra?

P124B indicates that the Injector 4 Positive Voltage Control Circuit is shorted to the control circuit, meaning there is an electrical issue with the fuel injector's wiring or components.

2. What are the common symptoms of code P124B on a 2017 GMC Sierra?

Symptoms may include rough idling, reduced engine performance, misfiring, poor fuel economy, or the Check Engine Light being illuminated.

3. What causes the P124B code to appear on a 2017 GMC Sierra?

Common causes include damaged or corroded wiring, a short circuit in the injector circuit, a faulty fuel injector, or a malfunctioning powertrain control module (PCM).

4. Can I drive my 2017 GMC Sierra with a P124B code?

Driving with this code is not recommended, as it can cause poor performance, increased emissions, and potential engine damage if not addressed promptly.

5. How do I diagnose a P124B code on a 2017 GMC Sierra?

Start by inspecting the wiring and connections for Injector 4, looking for damage or corrosion. Use a multimeter to check continuity and voltage, and test the injector for proper function.

6. How do I fix the P124B code on a 2017 GMC Sierra?

Repair or replace any damaged wiring, connectors, or the injector itself. If the issue persists, further diagnostics may be needed to check the PCM or related circuits.

7. How much does it cost to repair the P124B code on a 2017 GMC Sierra?

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

8. Can a bad PCM cause the P124B code on a 2017 GMC Sierra?

Yes, a malfunctioning PCM can cause this code, but it is less common. Always rule out wiring and injector issues before suspecting the PCM.

9. Will clearing the P124B code fix the issue on a 2017 GMC Sierra?

Clearing the code will temporarily turn off the Check Engine Light, but the issue will return if the underlying problem is not addressed.

10. Is the P124B code specific to Injector 4 on a 2017 GMC Sierra?

Yes, this code specifically pertains to the positive voltage control circuit for Injector 4. Other injectors would trigger similar codes with different numbers.