AutoCodes – GMC – P0800 2015 GMC Sierra

P0800 2015 GMC Sierra Code - Active Transfer Case Control Module Requested MIL Illumination

Quick Answer

Control modules constantly monitor the vehicle for any condition which may adversely affect vehicle performance. Common causes include Check Active Transfer Case Control Module for codes, Faulty Active Transfer Case Control Module. 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: P0800 2015 GMC Sierra indicates Active Transfer Case Control Module Requested MIL Illumination.
Common causes: Common causes include Check Active Transfer Case Control Module for codes, Faulty Active Transfer Case Control Module.
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 194

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 Jul 15, 2022

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code P0800 2015 GMC Sierra Description

Control modules constantly monitor the vehicle for any condition which may adversely affect vehicle performance. If a condition is detected, the module sets a Diagnostic Trouble Code (DTC) and sends a serial data message to the Engine Control Module (ECM). The ECM sets a DTC to inform that the module has set a DTC. The serial data message sent by the module also contains a request for the ECM to illuminate the Malfunction Indicator Lamp (MIL).
The DTC will be set when the ECM receives a serial data message from the Active Transfer Case Control Module indicating that DTC has been set in the module.

OBDII Code P0800 2015 GMC Sierra - Active Transfer Case Control Module Requested MIL Illumination - AutoCodes.com — P0800 2015 GMC Sierra Code - Active Transfer Case Control Module Requested MIL Illumination

What does this mean?

What are the Possible Causes of the DTC P0800 2015 GMC Sierra?

Check Active Transfer Case Control Module for codes
Faulty Active Transfer Case Control Module

How to Fix the DTC P0800 2015 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 P0800 2015 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 P0800 2015 GMC Sierra code?

Need more information on how to fix the P0800 2015 GMC Sierra code? Get Access to Factory Service Manuals

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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 P0800 2015 GMC Sierra Code

1. What does the OBDII code P0800 mean on a 2015 GMC Sierra?

P0800 indicates that the Active Transfer Case Control Module has requested the Malfunction Indicator Lamp (MIL) to be illuminated, signaling a potential issue in the transfer case system.

2. What are the common symptoms of the P0800 code?

Common symptoms include the check engine light being on, shifting issues with the 4WD system, unusual noises from the transfer case, or the inability to switch between 2WD and 4WD modes.

3. What causes the P0800 code to appear on a 2015 GMC Sierra?

Possible causes include a malfunctioning transfer case control module, wiring or connector issues, a faulty transfer case motor, or software/communication errors in the 4WD system.

4. Can I continue driving my 2015 GMC Sierra with the P0800 code active?

While the vehicle may still be drivable, ignoring the code could lead to further damage to the transfer case system or 4WD functionality, so itâ€™s best to address the issue promptly.

5. How is the P0800 code diagnosed?

A technician will typically use a scan tool to check for related codes, inspect the transfer case control module and associated wiring, and test the functionality of the 4WD system components.

6. How do you fix the P0800 code on a 2015 GMC Sierra?

Repairs may include replacing a faulty transfer case control module, repairing or replacing damaged wiring or connectors, reprogramming the module, or replacing the transfer case motor if defective.

7. Does the P0800 code always mean the transfer case control module is bad?

No, the code could also be caused by wiring issues, a faulty transfer case motor, or software-related problems rather than a failing control module.

8. How much does it cost to repair the P0800 code on a 2015 GMC Sierra?

Repair costs vary depending on the root cause but could range from $100 for wiring repairs to $1,000 or more if the transfer case control module or motor needs replacement.

9. Can a software update fix the P0800 code?

In some cases, a software update for the transfer case control module may resolve communication errors or bugs causing the code.

10. How can I prevent the P0800 code from returning?

Regular maintenance of the 4WD system, ensuring connections are secure, and addressing any transfer case system issues promptly can help prevent the code from recurring.