AutoCodes – Chevrolet – U029E Chevrolet

U029E Chevrolet Code - Lost Communication with NOX Sensor Module 2 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 2, Nitrogen Oxide Sensor Module 2 harness is open or shorted, Nitrogen Oxide Sensor Module 2 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: U029E Chevrolet indicates Lost Communication with NOX Sensor Module 2 Malfunction.
Common causes: Common causes include Faulty Nitrogen Oxide (NOx) Sensor Module 2, Nitrogen Oxide Sensor Module 2 harness is open or shorted, Nitrogen Oxide Sensor Module 2 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 8,765

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 U029E Chevrolet 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 U029E Chevrolet - Lost Communication with NOX Sensor Module 2 Malfunction - AutoCodes.com — U029E Chevrolet Code - Lost Communication with NOX Sensor Module 2 Malfunction

What does this mean?

What are the Possible Causes of the DTC U029E Chevrolet?

Faulty Nitrogen Oxide (NOx) Sensor Module 2
Nitrogen Oxide Sensor Module 2 harness is open or shorted
Nitrogen Oxide Sensor Module 2 circuit poor electrical connection

How to Fix the DTC U029E Chevrolet?

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 U029E Chevrolet 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 U029E Chevrolet code?

Need more information on how to fix the U029E Chevrolet code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the U029E Chevrolet code diagnosed by a professional: Find a repair shop in your area

Information for Specific Chevrolet Models

U029E 2014 Chevrolet Silverado — Lost Communication with NOX Sensor Module 2 Malfunction
U029E 2015 Chevrolet Silverado — Lost Communication with NOX Sensor Module 2 Malfunction
U029E 2016 Chevrolet Silverado — Lost Communication with NOX Sensor Module 2 Malfunction
U029E 2017 Chevrolet Silverado — Lost Communication with NOX Sensor Module 2 Malfunction
U029E 2018 Chevrolet Silverado — Lost Communication with NOX Sensor Module 2 Malfunction

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 U029E Chevrolet Code

1. What are the common symptoms of OBDII code U029E in a Chevrolet indicating a Lost Communication with NOX Sensor Module 2 Malfunction?

The common symptoms include the illumination of the Check Engine Light, decreased fuel efficiency, and potential issues with the vehicle's emission system.

2. What are some possible causes of the U029E code in a Chevrolet related to the NOX Sensor Module 2 malfunction?

Possible causes include a faulty NOX sensor, damaged wiring or connectors, a software update requirement, or issues with the Engine Control Module (ECM).

3. How serious is the U029E code in a Chevrolet, signaling a Lost Communication with NOX Sensor Module 2 Malfunction?

While the severity can vary, it is important to address this issue promptly to ensure proper functioning of the emission control system and to prevent potential long-term damage to the vehicle.

4. Can I continue driving my Chevrolet with the U029E code present?

It is generally not recommended to continue driving the vehicle with the U029E code active, as it can lead to decreased fuel efficiency and potentially cause further damage to the emission system.

5. How can I diagnose and repair the U029E code in my Chevrolet related to the NOX Sensor Module 2 malfunction?

Diagnosis typically involves using an OBDII scanner to retrieve the specific fault codes and then inspecting the NOX sensor, wiring, and connectors for any visible damage. Repair may involve replacing the NOX sensor, repairing damaged wiring, or updating the software as needed.

6. Can a DIY enthusiast fix the U029E code in a Chevrolet themselves?

While some basic troubleshooting steps can be taken by a DIY enthusiast, diagnosing and repairing issues related to the NOX Sensor Module 2 malfunction may require specialized tools and expertise, so it is recommended to consult a professional mechanic for proper diagnosis and repair.

7. How much does it cost to repair the U029E code in a Chevrolet?

The cost of repairing the U029E code can vary depending on the specific cause of the issue, the extent of the damage, and the labor rates in your area. It is advisable to obtain quotes from different mechanics to compare prices.

8. Will resetting the trouble codes make the U029E code disappear permanently?

Simply resetting the trouble codes may temporarily clear the Check Engine Light, but if the underlying issue causing the U029E code is not addressed, the code is likely to reappear. It is important to diagnose and repair the root cause of the problem.

9. Is the U029E code specific to Chevrolet vehicles, or can it occur in other car makes and models?

While the U029E code is specific to Chevrolet vehicles, similar codes related to NOX sensor malfunctions may appear in other car makes and models, each with its own unique diagnostic procedures and repair requirements.

10. How can I prevent the U029E code from occurring in my Chevrolet in the future?

Regular maintenance of your vehicle, including inspecting and replacing sensors as needed, keeping up with software updates, and addressing any issues promptly, can help prevent the U029E code from occurring in the future.