AutoCodes – GMC – P119B 2017 GMC Sierra

P119B 2017 GMC Sierra Code - NOx Sensor 1 Signal Circuit Low Voltage

Quick Answer

The Nitrogen Oxides (NOx) sensors are part of the selective catalytic reduction system, a device used to reduce NOx emission on diesel engines. Common causes include Faulty Nitrogen Oxides (NOx) Sensor, Nitrogen Oxides Sensor harness is open or shorted, Nitrogen Oxides Sensor 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: P119B 2017 GMC Sierra indicates NOx Sensor 1 Signal Circuit Low Voltage.
Common causes: Common causes include Faulty Nitrogen Oxides (NOx) Sensor, Nitrogen Oxides Sensor harness is open or shorted, Nitrogen Oxides Sensor 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 230

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 Mar 24, 2024

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code P119B 2017 GMC Sierra Description

The Nitrogen Oxides (NOx) sensors are part of the selective catalytic reduction system, a device used to reduce NOx emission on diesel engines. There are two NOx sensors, one placed upstream of selective catalytic reduction, to measure inlet NOx concentration, and one placed downstream. They are connected with the control module via CAN and all the information is exchanged through it. Since it is a smart sensor, all the electrical monitoring is performed inside the sensor and only the results are sent to the Engine Control Module (ECM). 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 the 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 (reductant) added by varying the reductant injector duty cycle in response to changes in engine exhaust 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. The Diagnostic Trouble Code (DTC) will be set if the ECM software detects a fault in the NOx sensor circuitry or a performance fault in the NOx sensor for greater than 2 s.

OBDII Code P119B 2017 GMC Sierra - NOx Sensor 1 Signal Circuit Low Voltage - AutoCodes.com — P119B 2017 GMC Sierra Code - NOx Sensor 1 Signal Circuit Low Voltage

What does this mean?

What are the Possible Causes of the DTC P119B 2017 GMC Sierra?

Faulty Nitrogen Oxides (NOx) Sensor
Nitrogen Oxides Sensor harness is open or shorted
Nitrogen Oxides Sensor circuit poor electrical connection

How to Fix the DTC P119B 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 P119B 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.

Need more information about the P119B 2017 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 P119B 2017 GMC Sierra Code

1. What does the OBDII code P119B mean on a 2017 GMC Sierra?

P119B indicates a "NOx Sensor 1 Signal Circuit Low Voltage," meaning the Engine Control Module (ECM) has detected a low voltage signal from the upstream nitrogen oxide (NOx) sensor.

2. What are the symptoms of code P119B in a 2017 GMC Sierra?

Common symptoms include reduced engine performance, increased fuel consumption, illuminated check engine light, and possible diesel exhaust fluid (DEF) system warnings.

3. What causes the P119B code to appear on a 2017 GMC Sierra?

Possible causes include a faulty NOx sensor, damaged sensor wiring, poor electrical connections, or a malfunctioning ECM.

4. Where is NOx Sensor 1 located on a 2017 GMC Sierra?

NOx Sensor 1 is typically located upstream of the Selective Catalytic Reduction (SCR) system, near the exhaust manifold or downpipe.

5. Can I drive my 2017 GMC Sierra with a P119B code?

Driving with a P119B code is not recommended, as it may lead to increased emissions, reduced fuel efficiency, and potential damage to the exhaust aftertreatment system.

6. How do I diagnose a P119B code on my 2017 GMC Sierra?

Diagnosis involves using a scan tool to verify the code, inspecting the NOx sensor and its wiring for damage, and testing the sensor's voltage and resistance.

7. How do I fix the P119B code on a 2017 GMC Sierra?

Repairs may include replacing the NOx sensor, repairing or replacing damaged wiring, cleaning electrical connections, or reprogramming the ECM if necessary.

8. How much does it cost to fix a P119B code on a 2017 GMC Sierra?

Repair costs can range from $200 to $600 or more, depending on whether the NOx sensor or wiring needs replacement and labor rates in your area.

9. Can a dirty exhaust system cause the P119B code?

Yes, excessive soot or buildup in the exhaust system can affect the NOx sensor's performance and lead to a P119B code.

10. Will clearing the P119B code fix the issue permanently?

Clearing the code without addressing the underlying problem will not fix the issue, and the code will likely return after a short period. Proper diagnosis and repair are necessary.