AutoCodes – GMC – P1899 GMC

P1899 GMC 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 GMC 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.

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Code Popularity 128

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
Comments
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Code P1899 GMC 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 GMC - Axle Torque Secondary Signal Message Counter Incorrect - AutoCodes.com — P1899 GMC Code - Axle Torque Secondary Signal Message Counter Incorrect

What does this mean?

What are the Possible Causes of the DTC P1899 GMC?

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 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 P1899 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.

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Information for Specific GMC Models

P1899 2014 GMC Sierra — Axle Torque Secondary Signal Message Counter Incorrect
P1899 2015 GMC Sierra — Axle Torque Secondary Signal Message Counter Incorrect
P1899 2016 GMC Sierra — Axle Torque Secondary Signal Message Counter Incorrect
P1899 2017 GMC Sierra — Axle Torque Secondary Signal Message Counter Incorrect
P1899 2018 GMC Sierra — Axle Torque Secondary Signal Message Counter Incorrect

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.