AutoCodes – GMC – P119B GMC

P119B GMC 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 GMC 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.

Save to My Repairs My Repairs

AI answers can be wrong. Verify repairs with testing. Open full chat

Code Popularity 546

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Advanced (Pro) (3 / 3)

What is this?

Table of contents Created and updated by William Orellana on Mar 29, 2024

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
Add Comment

💬 Need more help? Ask Coddy for instant answers — it's free!

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

What does this mean?

What are the Possible Causes of the DTC P119B GMC?

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 GMC?

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 GMC 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 GMC code?

Need more information on how to fix the P119B GMC code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the P119B GMC code diagnosed by a professional: Find a repair shop in your area

Information for Specific GMC Models

P119B 2014 GMC Sierra — NOx Sensor 1 Signal Circuit Low Voltage
P119B 2015 GMC Sierra — NOx Sensor 1 Signal Circuit Low Voltage
P119B 2016 GMC Sierra — NOx Sensor 1 Signal Circuit Low Voltage
P119B 2017 GMC Sierra — NOx Sensor 1 Signal Circuit Low Voltage
P119B 2018 GMC Sierra — NOx Sensor 1 Signal Circuit Low Voltage

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 GMC Code

1. What are the common symptoms of OBDII code P119B GMC related to the NOx Sensor 1 Signal Circuit Low Voltage?

- Common symptoms include poor engine performance, decreased fuel efficiency, rough idling, and potential illumination of the Check Engine Light.

2. What are some possible causes of the NOx Sensor 1 Signal Circuit Low Voltage fault code?

- Causes can include a faulty NOx sensor, wiring issues in the sensor circuit, exhaust leaks, or a problem with the engine control module (ECM).

3. How can I diagnose the cause of the P119B GMC code related to the NOx sensor?

- Diagnosis typically involves checking the sensor's electrical connections, inspecting the sensor for physical damage, testing the wiring for continuity, and using a diagnostic scanner for further analysis.

4. Can a faulty NOx sensor be repaired, or does it need to be replaced?

- In most cases, a faulty NOx sensor will need to be replaced as it is a critical component for emissions control and accurate engine performance.

5. Are there any DIY repair tips for addressing the NOx Sensor 1 Signal Circuit Low Voltage issue?

- DIY repair tips include checking and cleaning the electrical connections, inspecting wiring harnesses for damage, and ensuring proper installation of a new sensor if replacement is necessary.

6. How serious is the P119B GMC fault code related to the NOx sensor?

- While the vehicle may still be drivable with this fault code, it is important to address it promptly to prevent potential long-term damage to the engine and to maintain optimal emissions control.

7. Can driving with the NOx Sensor 1 Signal Circuit Low Voltage fault code cause further damage to the vehicle?

- Continued driving with this fault code can lead to increased emissions, reduced fuel efficiency, and potential damage to the catalytic converter or other emission control components.

8. Is it safe to reset the Check Engine Light after addressing the P119B GMC code?

- It is recommended to clear the fault code and reset the Check Engine Light after addressing the issue to ensure proper monitoring of the vehicle's performance and emissions.

9. How much does it typically cost to replace a NOx sensor related to the P119B GMC code?

- The cost of replacing a NOx sensor can vary depending on the vehicle make and model, but it generally ranges from $200 to $500 for parts and labor.

10. Can a professional mechanic help diagnose and repair the NOx Sensor 1 Signal Circuit Low Voltage issue?

- Yes, a qualified mechanic with experience in automotive diagnostics can accurately diagnose and repair the NOx sensor-related fault code to ensure the vehicle operates efficiently and complies with emission regulations.