AutoCodes – GMC – U029D 2014 GMC Sierra

U029D 2014 GMC Sierra Code - Lost Communication with NOX Sensor Module 1 Malfunction

Quick Answer

The reductant system uses two Nitrogen Oxide (NOx) sensors to monitor the amount of NOx in the engine's exhaust gas. Common causes include Faulty Nitrogen Oxide (NOx) Sensor Module 1, Nitrogen Oxide Sensor Module 1 harness is open or shorted, Nitrogen Oxide Sensor Module 1 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: U029D 2014 GMC Sierra indicates Lost Communication with NOX Sensor Module 1 Malfunction.
Common causes: Common causes include Faulty Nitrogen Oxide (NOx) Sensor Module 1, Nitrogen Oxide Sensor Module 1 harness is open or shorted, Nitrogen Oxide Sensor Module 1 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 216

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 Oct 18, 2022

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code U029D 2014 GMC Sierra Description

The reductant system uses two Nitrogen Oxide (NOx) sensors to monitor the amount of NOx in the engine's exhaust gas. The first sensor is located at the outlet of the turbocharger and monitors the engine out NOx level. The second NOx sensor is located between the Selective Catalytic Reduction (SCR) and the Diesel Particulate Filter (DPF) and monitors NOx levels downstream of the SCR. The second NOx sensor also provides the Engine Control Module (ECM) with information on the exhaust oxygen level during DPF regeneration.
Each NOx sensor contains a sensing cell, a pumping cell, and a heater. A sample of exhaust gas passes through a diffusion gap between the sensing cell and the pumping cell. The NOx sensor maintains a constant reference voltage across the sensing cell. An electronic circuit within sensor controls the pump current through the pumping cell in order to maintain a constant voltage in the sensing cell. The amount of current required to maintain the reference voltage in the sensing cell is proportional to the concentration of NOx in the exhaust.
The ECM varies the amount of Diesel Exhaust Fluid (DEF) or reductant added by varying the reductant injector duty cycle in response to changes in engine exhaust out NOx levels. The smart NOx sensors consist of two components, the NOx module and the NOx sensor element that are serviced as a unit. A circuit or performance condition with a NOx sensor is detected by the NOx sensor module. The smart NOx sensor module communicates the condition to the ECM over the serial data line. The ECM sets a DTC when a serial data message is received from the NOx sensor module.

OBDII Code U029D 2014 GMC Sierra - Lost Communication with NOX Sensor Module 1 Malfunction - AutoCodes.com — U029D 2014 GMC Sierra Code - Lost Communication with NOX Sensor Module 1 Malfunction

What does this mean?

What are the Possible Causes of the DTC U029D 2014 GMC Sierra?

Faulty Nitrogen Oxide (NOx) Sensor Module 1
Nitrogen Oxide Sensor Module 1 harness is open or shorted
Nitrogen Oxide Sensor Module 1 circuit poor electrical connection

How to Fix the DTC U029D 2014 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 U029D 2014 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 U029D 2014 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 U029D 2014 GMC Sierra Code

1. What are the common symptoms of OBDII code U029D in a 2014 GMC Sierra related to the NOX Sensor Module 1 malfunction?

The common symptoms include the check engine light illuminating, reduced engine performance, and potential issues with emissions control.

2. What causes the "Lost Communication with NOX Sensor Module 1 Malfunction" code (U029D) to appear in a 2014 GMC Sierra?

The code U029D typically indicates a communication problem between the engine control module (ECM) and the NOX sensor module, which can be due to wiring issues, a faulty module, or software glitches.

3. How can I diagnose the U029D code related to the NOX sensor in my 2014 GMC Sierra?

Diagnosing the U029D code involves checking the wiring connections between the ECM and the NOX sensor module, inspecting for any physical damage, and utilizing a diagnostic scan tool to retrieve more information about the communication fault.

4. Can a DIY enthusiast repair the U029D code linked to the NOX sensor issue in a 2014 GMC Sierra?

While some basic troubleshooting steps can be done by DIY enthusiasts, resolving the U029D code may require advanced diagnostic equipment and technical expertise due to the complexities of the NOX sensor system.

5. Are there any temporary fixes or workarounds for the U029D code until I can get it professionally repaired in my 2014 GMC Sierra?

Temporary fixes for the U029D code are not recommended as they may further damage the emissions control system or lead to other issues. It is best to address the problem promptly to avoid potential engine performance issues.

6. What are the potential long-term effects of ignoring the U029D code related to the NOX sensor module malfunction in a 2014 GMC Sierra?

Ignoring the U029D code can lead to increased emissions, reduced fuel efficiency, and potentially cause damage to other engine components over time, resulting in more costly repairs.

7. How much does it typically cost to repair the U029D code associated with the NOX sensor module problem in a 2014 GMC Sierra?

The cost of repairing the U029D code can vary depending on the underlying cause of the issue. It is advisable to consult with a professional mechanic or dealership for an accurate diagnosis and cost estimate.

8. Is it safe to continue driving a 2014 GMC Sierra with the U029D code triggered by the NOX sensor module malfunction?

Continuing to drive the vehicle with the U029D code illuminated is not recommended as it can lead to potential engine performance issues and further damage to the emissions control system. It is advisable to have the problem addressed as soon as possible.

9. Can a faulty NOX sensor itself trigger the U029D code in a 2014 GMC Sierra?

While a faulty NOX sensor can contribute to the communication issues between the ECM and the sensor module, the U029D code is more commonly associated with communication problems rather than a faulty sensor itself.

10. How long does it typically take to repair the U029D code linked to the NOX sensor module in a 2014 GMC Sierra?

The repair time for the U029D code can vary based on the specific cause of the issue. It may range from a few hours to a full day, depending on the complexity of the repair and availability of parts.