AutoCodes – GMC – P119E 2018 GMC Sierra

P119E 2018 GMC Sierra Code - NOx Sensor 2 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 2, Nitrogen Oxides Sensor 2 harness is open or shorted, Nitrogen Oxides Sensor 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: P119E 2018 GMC Sierra indicates NOx Sensor 2 Signal Circuit Low Voltage.
Common causes: Common causes include Faulty Nitrogen Oxides (NOx) Sensor 2, Nitrogen Oxides Sensor 2 harness is open or shorted, Nitrogen Oxides Sensor 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 202

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 24, 2024

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code P119E 2018 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 P119E 2018 GMC Sierra - NOx Sensor 2 Signal Circuit Low Voltage - AutoCodes.com — P119E 2018 GMC Sierra Code - NOx Sensor 2 Signal Circuit Low Voltage

What does this mean?

What are the Possible Causes of the DTC P119E 2018 GMC Sierra?

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

How to Fix the DTC P119E 2018 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 P119E 2018 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 P119E 2018 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 P119E 2018 GMC Sierra Code

What does the OBDII code P119E mean on a 2018 GMC Sierra?

P119E indicates that the NOx Sensor 2 (downstream sensor) is detecting a low voltage signal in its circuit, which can affect the vehicle's emissions control system.

What are the common symptoms of code P119E in a 2018 GMC Sierra?

Common symptoms include the check engine light turning on, reduced engine performance, increased emissions, and possible fuel efficiency loss.

What causes the P119E code to appear?

Possible causes include a faulty NOx Sensor 2, damaged or corroded wiring, poor electrical connections, or issues with the Engine Control Module (ECM).

Can I drive my 2018 GMC Sierra with code P119E?

Driving with this code is not recommended, as it can lead to higher emissions and potential damage to the emissions system if left unresolved.

How do I diagnose P119E on a 2018 GMC Sierra?

Start by scanning with an OBDII tool to confirm the code, then inspect the NOx Sensor 2, its wiring, and connectors for damage or corrosion. Further testing may involve checking the voltage and resistance of the sensor circuit.

How do you fix the P119E code?

Repairs may involve replacing the NOx Sensor 2, repairing or replacing damaged wiring or connectors, or reprogramming/updating the ECM if required.

How much does it cost to fix P119E on a 2018 GMC Sierra?

The cost depends on the issue. Replacing the NOx sensor typically ranges from $300 to $700, including parts and labor, while wiring repairs may cost less.

Can a dirty DEF system cause P119E?

Yes, contamination or issues in the Diesel Exhaust Fluid (DEF) system can contribute to sensor faults, as it affects NOx detection and emissions control.

How often do NOx sensors fail in a 2018 GMC Sierra?

NOx sensors can fail due to age, contamination, or extreme operating conditions. They typically last 80,000 to 150,000 miles but may fail sooner under harsh conditions.

Will clearing the P119E code fix the problem?

Clearing the code may turn off the check engine light temporarily, but it won't fix the underlying issue, and the code is likely to return until the problem is resolved.