U029E 2017 GMC Sierra 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 2017 GMC Sierra 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.
Code U029E 2017 GMC Sierra Description
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.
What are the Possible Causes of the DTC U029E 2017 GMC Sierra?
- 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 2017 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 U029E 2017 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.
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Frequently Asked Questions about U029E 2017 GMC Sierra Code
1. What does OBDII code U029E mean on a 2017 GMC Sierra?
Code U029E indicates a loss of communication between the vehicle’s main computer and the NOx Sensor Module 2, which monitors nitrogen oxide emissions.
2. What are the symptoms of code U029E on a 2017 GMC Sierra?
Common symptoms include the check engine light turning on, decreased fuel efficiency, possible reduced engine power, and failure to pass emissions tests.
3. What causes the U029E code on a GMC Sierra?
Potential causes include a faulty NOx Sensor Module 2, damaged wiring or connectors in the communication circuit, or an issue with the vehicle's ECU.
4. Can I drive my 2017 GMC Sierra with a U029E code?
While the vehicle may still be drivable, it could experience reduced performance and higher emissions. Addressing the issue promptly is recommended to avoid further damage.
5. How do I diagnose the U029E code on my GMC Sierra?
Check for damaged wiring or loose connections around the NOx sensor module, test the sensor for proper function, and verify the integrity of the communication circuit with a diagnostic tool.
6. How do I fix the U029E code on a 2017 GMC Sierra?
Repairs may include replacing a faulty NOx Sensor Module 2, repairing damaged wiring, cleaning corroded connectors, or updating/reprogramming the ECU if needed.
7. How much does it cost to fix the U029E code on a GMC Sierra?
Costs vary depending on the repair. Replacing the NOx sensor can cost $400–$900, while wiring repairs or diagnostics may cost less.
8. Can a software update fix the U029E code on my GMC Sierra?
In some cases, an ECU software update or reprogramming may resolve communication issues between the ECU and the NOx sensor module.
9. What tools are needed to troubleshoot the U029E code?
You’ll need an OBDII scanner with advanced diagnostic capabilities, a multimeter for testing wiring, and a service manual for wiring diagrams.
10. Is U029E a common issue on the 2017 GMC Sierra?
While not extremely common, communication errors like U029E can occur, especially in vehicles with high mileage or exposure to harsh environmental conditions.
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