AutoCodes – GMC – P1899 2015 GMC Sierra

P1899 2015 GMC Sierra Code - Axle Torque Secondary Signal Message Counter Incorrect

Quick Answer

The Magna Powertrain (MP) transfer case is a 1-speed automatic, Active Transfer Case (ATC). Common causes include Faulty Transfer Case Control Module, Transfer Case Control Module harness is open or shorted, Transfer Case Control Module 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: P1899 2015 GMC Sierra indicates Axle Torque Secondary Signal Message Counter Incorrect.
Common causes: Common causes include Faulty Transfer Case Control Module, Transfer Case Control Module harness is open or shorted, Transfer Case Control Module 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 70

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 Jun 18, 2025

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 P1899 2015 GMC Sierra Description

The Magna Powertrain (MP) transfer case is a 1-speed automatic, Active Transfer Case (ATC). The MP ATC provides 3 modes, Auto 4WD, 4HI, and 2HI. The Auto 4WD position allows the capability of an active transfer case, which provides the benefits of on-demand torque biasing wet clutch and easy vehicle tuning through software calibrations. The software calibrations allow more features, such as flexible adapt ready position and clutch preload torque levels. The technology allows for vehicle speed dependent clutch toque levels to enhance the performance of the system. For example, the system is calibrated to provide 0–6.78 N•m (0–5 lb ft) of clutch torque during low speed, low engine torque operation, and predetermined higher torque for 40 km/h (25 mph) and greater. This prevents crow-hop and binding at low speeds and provides higher torque biases at higher vehicle speeds, in order to enhance stability. The Powertrain Control Module (PCM) monitors the Axle Torque Secondary signal messages. The PCM sets the Diagnostic Trouble Code (DTC) when the Axle Torque Secondary signal message counter is incorrect.

OBDII Code P1899 2015 GMC Sierra - Axle Torque Secondary Signal Message Counter Incorrect - AutoCodes.com — P1899 2015 GMC Sierra Code - Axle Torque Secondary Signal Message Counter Incorrect

What does this mean?

What are the Possible Causes of the DTC P1899 2015 GMC Sierra?

Faulty Transfer Case Control Module
Transfer Case Control Module harness is open or shorted
Transfer Case Control Module circuit poor electrical connection

How to Fix the DTC P1899 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 P1899 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 P1899 2015 GMC Sierra code?

Need more information on how to fix the P1899 2015 GMC Sierra code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the P1899 2015 GMC Sierra 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 P1899 2015 GMC Sierra Code

What does the OBD-II code P1899 mean for a 2015 GMC Sierra?

Code P1899 indicates an issue with the Axle Torque Secondary Signal Message Counter, meaning the system is detecting incorrect or invalid data communication from the axle torque module.

What are the common symptoms of code P1899 in a 2015 GMC Sierra?

Symptoms may include erratic shifting, reduced power output, transmission slipping, or the illumination of the check engine light.

What causes code P1899 in a 2015 GMC Sierra?

The code is typically caused by faulty wiring, a malfunctioning axle torque module, a failed transmission control module (TCM), or software glitches in the communication system.

Can code P1899 cause drivability issues in a 2015 GMC Sierra?

Yes, this code can lead to transmission performance problems, including rough shifting and reduced torque delivery during acceleration.

How is code P1899 diagnosed on a 2015 GMC Sierra?

Diagnosis involves using a scan tool to monitor live data, inspecting wiring and connections to the axle torque module, and testing the module for proper functionality.

Can code P1899 be fixed without replacing components?

In some cases, the issue may be resolved by repairing or replacing damaged wiring, cleaning electrical connections, or updating the transmission control module firmware.

What tools are needed to diagnose and repair code P1899 on a 2015 GMC Sierra?

A diagnostic scan tool, multimeter for testing electrical circuits, and potentially a software update tool for the TCM may be required.

Does code P1899 affect the transmission on a 2015 GMC Sierra?

Yes, since the code relates to axle torque communication, it can directly affect transmission performance and torque delivery.

Is it safe to drive with code P1899 in a 2015 GMC Sierra?

While the vehicle may still be drivable, ignoring this code can lead to worsening transmission issues, reduced performance, or potential safety concerns.

How much does it cost to repair code P1899 on a 2015 GMC Sierra?

Repair costs can vary widely depending on whether wiring repairs, module replacements, or software updates are needed, typically ranging from $150 to $1,000.