AutoCodes – GMC – P124B 2016 GMC Sierra

P124B 2016 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 2016 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 181

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 2016 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 2016 GMC Sierra - Injector 4 Positive Voltage Control Circuit Shorted to Control Circuit - AutoCodes.com — P124B 2016 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 2016 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 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 P124B 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 P124B 2016 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 2016 GMC Sierra Code

1. What does the OBDII code P124B mean on a 2016 GMC Sierra?

P124B indicates that the powertrain control module (PCM) has detected a short circuit between the positive voltage control circuit and the control circuit for fuel injector 4.

2. What are the common symptoms of the P124B code?

Common symptoms include rough idling, misfires, reduced engine performance, poor fuel efficiency, and an illuminated check engine light.

3. What causes the P124B code to appear?

Possible causes include damaged or shorted wiring to injector 4, a faulty fuel injector, a defective PCM, or poor electrical connections in the injector circuit.

4. Can I drive my 2016 GMC Sierra with the P124B code?

Itâ€™s not recommended to drive with this code active, as it can lead to engine damage, poor performance, or unsafe driving conditions.

5. How do I diagnose the P124B code?

Diagnosis typically involves inspecting the wiring harness for damage, testing the injector 4 circuit for continuity or shorts, and using a scan tool to monitor fuel injector operation.

6. How can I fix the P124B code?

Repairs may involve replacing damaged wiring, repairing electrical connections, replacing the faulty injector 4, or reprogramming/repairing the PCM if necessary.

7. How much does it cost to repair the P124B code?

Repair costs vary depending on the issue. Fixing wiring or connections may cost $100-$300, while replacing an injector or PCM can cost $500-$1000 or more.

8. Can a dirty or clogged injector cause the P124B code?

No, this code specifically refers to an electrical issue in the injector circuit, not a mechanical clogging issue.

9. What tools are needed to troubleshoot the P124B code?

Youâ€™ll need a multimeter to test wiring, a scan tool to read live data and codes, and possibly a wiring diagram for the vehicle.

10. Can a bad PCM cause the P124B code?

Yes, a faulty PCM could potentially cause this code if it fails to properly control the injector 4 circuit. However, this is less common and should be diagnosed after ruling out wiring and injector issues.