U029D 2017 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 2017 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.
Code U029D 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 U029D 2017 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 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 U029D 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 U029D 2017 GMC Sierra Code
1. What does the OBDII code U029D mean on a 2017 GMC Sierra?
The U029D code indicates that the vehicle's computer has lost communication with NOx Sensor Module 1, which monitors nitrogen oxide levels in the exhaust.
2. What are the common symptoms of the U029D code on a 2017 GMC Sierra?
Symptoms may include the check engine light turning on, reduced fuel efficiency, poor engine performance, or the vehicle entering limp mode.
3. What causes the U029D code to appear on a 2017 GMC Sierra?
Common causes include a faulty NOx sensor, damaged wiring or connectors, a failed sensor module, or issues with the vehicle’s powertrain control module (PCM).
4. Can I drive my 2017 GMC Sierra with the U029D code?
Driving with this code is possible but not recommended, as it can lead to poor emissions performance, reduced fuel economy, and potential damage to the exhaust system over time.
5. How do I diagnose the U029D code on my 2017 GMC Sierra?
Diagnose the code by inspecting the wiring and connectors for damage, testing the NOx sensor module, and using a scan tool to verify communication between the module and the PCM.
6. How do I fix the U029D code on a 2017 GMC Sierra?
Repairs may include replacing the NOx sensor, repairing damaged wiring, cleaning or securing loose connectors, or reprogramming the PCM if necessary.
7. How much does it cost to repair the U029D code on a 2017 GMC Sierra?
Repair costs vary but may range from $200 to $600, depending on whether the NOx sensor, wiring, or module needs to be replaced or repaired.
8. Can a software update fix the U029D code on my 2017 GMC Sierra?
In some cases, a software update for the PCM or related modules may resolve miscommunication issues causing the code.
9. What tools are required to troubleshoot the U029D code?
Troubleshooting typically requires a professional-grade OBDII scan tool, a multimeter for testing electrical components, and possibly a wiring diagram for the NOx sensor circuit.
10. Does the U029D code affect emissions testing?
Yes, the U029D code can cause your vehicle to fail an emissions test, as it impacts the monitoring of nitrogen oxide levels in the exhaust.
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