AutoCodes – GMC – U029D 2016 GMC Sierra

U029D 2016 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 2016 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 213

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 2016 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 2016 GMC Sierra - Lost Communication with NOX Sensor Module 1 Malfunction - AutoCodes.com — U029D 2016 GMC Sierra Code - Lost Communication with NOX Sensor Module 1 Malfunction

What does this mean?

What are the Possible Causes of the DTC U029D 2016 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 2016 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 2016 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 2016 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 2016 GMC Sierra Code

1. What are the common symptoms of OBDII code U029D in a 2016 GMC Sierra?

The common symptoms of U029D code include the Check Engine Light (CEL) illuminating on the dashboard, reduced engine performance, and potential issues with the vehicle's emissions system.

2. What does the OBDII code U029D in a 2016 GMC Sierra indicate?

The U029D code specifically indicates a "Lost Communication with NOX Sensor Module 1 Malfunction." This means there is a communication problem between the engine control module and the NOX sensor module.

3. What are some possible causes of the U029D code in a 2016 GMC Sierra?

Possible causes of the U029D code include damaged wiring or connectors, a faulty NOX sensor module, a malfunctioning engine control module, or a software issue.

4. How can I diagnose the U029D code in my 2016 GMC Sierra?

Diagnosing the U029D code typically involves using a diagnostic scanner to retrieve the specific fault code, checking the wiring and connectors for any damage, testing the NOX sensor module, and verifying the communication between modules.

5. Can I still drive my 2016 GMC Sierra with the U029D code present?

It is not recommended to drive your vehicle with the U029D code present, as it can lead to reduced engine performance and potential emissions issues. It is best to address the problem promptly.

6. How can I repair the U029D code in my 2016 GMC Sierra?

Repairing the U029D code may involve repairing or replacing damaged wiring or connectors, replacing the NOX sensor module if faulty, reprogramming the engine control module, or addressing any software issues.

7. Is the U029D code in a 2016 GMC Sierra a serious issue?

While the U029D code may not cause immediate harm to the vehicle, it should be addressed promptly to prevent potential damage to the emissions system and ensure optimal engine performance.

8. Can a DIY enthusiast fix the U029D code in a 2016 GMC Sierra?

DIY enthusiasts with experience in automotive diagnostics and repairs may be able to address the U029D code by following the diagnostic procedures and repairing or replacing components as needed.

9. How much does it cost to repair the U029D code in a 2016 GMC Sierra?

The cost of repairing the U029D code can vary depending on the specific cause of the issue, the extent of the repairs needed, and whether you choose to address it yourself or seek professional help. Costs may include parts and labor.

10. How often does the U029D code occur in a 2016 GMC Sierra?

The U029D code can occur sporadically or more frequently depending on the underlying cause. Regular maintenance and prompt attention to any detected issues can help prevent the recurrence of this code.