AutoCodes – GMC – P3056 GMC

P3056 GMC Code - DC/DC Converter Actuator Voltage 2 Performance

Quick Answer

The Power Supply Transformer is used to boost battery voltage to sensitive loads during engine restart. Common causes include Faulty Power Supply Transformer, Power Supply Transformer harness is open or shorted, Power Supply Transformer 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: P3056 GMC indicates DC/DC Converter Actuator Voltage 2 Performance.
Common causes: Common causes include Faulty Power Supply Transformer, Power Supply Transformer harness is open or shorted, Power Supply Transformer 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.

Save to My Repairs My Repairs

AI answers can be wrong. Verify repairs with testing. Open full chat

Code Popularity 10,351

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 May 16, 2019

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
Add Comment

💬 Need more help? Ask Coddy for instant answers — it's free!

Code P3056 GMC Description

The Power Supply Transformer is used to boost battery voltage to sensitive loads during engine restart. It provides two voltage outputs that provide the boosted voltage. The Power Supply Transformer communicates to the Engine Control Module (ECM). When the engine is not cranking, the Power Supply Transformer passes through voltage from the two supply circuits. The ECM receives data about the sensed output voltages provided by the Power Supply Transformer.

OBDII Code P3056 GMC - DC/DC Converter Actuator Voltage 2 Performance - AutoCodes.com — P3056 GMC Code - DC/DC Converter Actuator Voltage 2 Performance

What does this mean?

What are the Possible Causes of the DTC P3056 GMC?

Faulty Power Supply Transformer
Power Supply Transformer harness is open or shorted
Power Supply Transformer circuit poor electrical connection

How to Fix the DTC P3056 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 is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P3056 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 P3056 GMC code?

Need more information on how to fix the P3056 GMC code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the P3056 GMC code diagnosed by a professional: Find a repair shop in your area

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 P3056 GMC Code

1. What are the common symptoms of OBDII code P3056 GMC (DC/DC Converter Actuator Voltage 2 Performance)?

The common symptoms include reduced fuel efficiency, poor engine performance, and potential stalling or hesitation while driving.

2. What are the possible causes of OBDII code P3056 GMC?

Possible causes of this code may include a faulty DC/DC converter actuator, wiring issues, a malfunctioning control module, or a poor electrical connection.

3. How can I diagnose the cause of OBDII code P3056 GMC?

Diagnosis typically involves using a scan tool to read the code, conducting a visual inspection of related components, checking wiring for damage, and testing the DC/DC converter actuator and control module.

4. Can I continue driving with OBDII code P3056 GMC?

It is not recommended to continue driving with this code active, as it can lead to further damage to the vehicle and potentially cause safety issues. Prompt diagnosis and repair are advised.

5. How do I repair OBDII code P3056 GMC?

Repairing this code may involve replacing the DC/DC converter actuator, repairing or replacing damaged wiring, resetting the control module, or addressing any loose connections.

6. Are there any DIY tips for fixing OBDII code P3056 GMC?

While some basic inspections can be done by DIY enthusiasts, diagnosing and repairing this specific code often requires specialized tools and expertise. It is recommended to consult with a professional mechanic.

7. How much does it cost to repair OBDII code P3056 GMC?

The cost of repairing this code can vary depending on the root cause of the issue, the extent of the damage, and labor rates in your area. It is advisable to obtain quotes from different repair shops.

8. Is OBDII code P3056 GMC a common issue in GMC vehicles?

While not as common as some other OBDII codes, P3056 related to DC/DC converter actuator voltage performance can occur in GMC vehicles, particularly in models equipped with this component.

9. Can a faulty battery cause OBDII code P3056 GMC to appear?

A weak or faulty battery can potentially contribute to electrical issues that may trigger OBDII code P3056. Ensuring the battery is in good condition is always a good maintenance practice.

10. Will resetting the OBDII system clear OBDII code P3056 GMC?

Resetting the OBDII system may temporarily clear the code, but if the underlying issue is not addressed, the code is likely to reappear. It is essential to diagnose and fix the root cause of the problem.