AutoCodes – GMC – U029D 2015 GMC Sierra

U029D 2015 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 2015 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 305

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 2015 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 2015 GMC Sierra - Lost Communication with NOX Sensor Module 1 Malfunction - AutoCodes.com — U029D 2015 GMC Sierra Code - Lost Communication with NOX Sensor Module 1 Malfunction

What does this mean?

What are the Possible Causes of the DTC U029D 2015 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 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 U029D 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 U029D 2015 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 2015 GMC Sierra Code

1. What are the common symptoms of OBDII code U029D in a 2015 GMC Sierra related to "Lost Communication with 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 could cause the U029D code in a 2015 GMC Sierra?

The U029D code is typically triggered by a communication breakdown between the engine control module (ECM) and the NOX sensor module 1, which could be due to wiring issues, a faulty sensor, or a defective ECM.

3. How can I diagnose the U029D code in my 2015 GMC Sierra?

Diagnosing the U029D code involves checking the wiring and connections related to the NOX sensor module 1, testing the sensor itself, and verifying the ECM's functionality using a diagnostic scanner.

4. Can I continue driving my 2015 GMC Sierra with the U029D code present?

While it may be possible to drive the vehicle with the U029D code, it is recommended to address the issue promptly to prevent potential damage to the emissions control system and ensure optimal engine performance.

5. What are the repair options for the U029D code in a 2015 GMC Sierra?

Repair options include repairing or replacing damaged wiring, replacing the NOX sensor module 1 if it is faulty, or reprogramming the ECM if necessary. Consulting a professional mechanic for a thorough diagnosis is advised.

6. Is the U029D code in a 2015 GMC Sierra a serious issue?

The U029D code indicates a malfunction related to the NOX sensor module 1 communication, which can impact emissions control and engine performance. While not an emergency, addressing the issue in a timely manner is recommended.

7. Can a DIY enthusiast fix the U029D code in a 2015 GMC Sierra?

DIY enthusiasts with automotive repair experience and access to diagnostic tools may be able to address the U029D code by checking and repairing wiring, replacing the NOX sensor module 1, or reprogramming the ECM if needed.

8. How much does it typically cost to repair the U029D code in a 2015 GMC Sierra?

The cost of repairing the U029D code can vary depending on the underlying cause, parts needed for replacement, and labor charges. It is advisable to obtain quotes from reputable mechanics or dealerships for an accurate estimation.

9. Will resetting the check engine light resolve the U029D code in a 2015 GMC Sierra?

Resetting the check engine light may temporarily turn it off, but it will not fix the underlying issue causing the U029D code. It is crucial to diagnose and address the root cause to prevent future problems.

10. How can I prevent the U029D code from reoccurring in my 2015 GMC Sierra?

To prevent the U029D code from reoccurring, regular maintenance of the NOX sensor system, including checking wiring integrity and ensuring proper connections, is essential. Additionally, timely addressing any related issues can help prevent future occurrences of the code.