AutoCodes – GMC – P116B 2018 GMC Sierra

P116B 2018 GMC Sierra Code - O2 Signal Circuit Low Voltage (NOx Sensor 1)

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: P116B 2018 GMC Sierra indicates O2 Signal Circuit Low Voltage (NOx Sensor 1).
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 152

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 P116B 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 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 P116B 2018 GMC Sierra - O2 Signal Circuit Low Voltage (NOx Sensor 1) - AutoCodes.com — P116B 2018 GMC Sierra Code - O2 Signal Circuit Low Voltage (NOx Sensor 1)

What does this mean?

What are the Possible Causes of the DTC P116B 2018 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 P116B 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 P116B 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 P116B 2018 GMC Sierra code?

Need more information on how to fix the P116B 2018 GMC Sierra code? Get Access to Factory Service Manuals

Need Help with the 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 P116B 2018 GMC Sierra Code

What does the OBDII code P116B mean on a 2018 GMC Sierra?

P116B indicates an issue with the O2 signal circuit of NOx Sensor 1, where the voltage is lower than expected, potentially affecting emissions control.

What are the common symptoms of code P116B on a 2018 GMC Sierra?

Symptoms may include the check engine light turning on, reduced fuel efficiency, poor engine performance, or increased exhaust emissions.

What causes the P116B code in a 2018 GMC Sierra?

Common causes include a faulty NOx sensor, damaged wiring or connectors in the O2 signal circuit, a malfunctioning ECM, or excessive soot buildup on the sensor.

Can I drive my 2018 GMC Sierra with code P116B active?

While the vehicle may still drive, it's not recommended as the issue can lead to increased emissions, reduced fuel economy, and potential damage to the catalytic converter over time.

How is the P116B code diagnosed on a 2018 GMC Sierra?

A technician will use a scan tool to read live data, check for wiring or connector issues, inspect the NOx sensor, and test the O2 signal circuit for proper voltage levels.

How do you fix the P116B code on a 2018 GMC Sierra?

Repairs may involve replacing the NOx sensor, repairing or replacing damaged wiring or connectors, cleaning the sensor if itâ€™s clogged, or reprogramming/updating the ECM if needed.

How much does it cost to repair the P116B code on a 2018 GMC Sierra?

Repair costs can range from $200 to $700 or more, depending on whether the NOx sensor, wiring, or ECM requires replacement or reprogramming.

Can a faulty NOx sensor cause other problems in a 2018 GMC Sierra?

Yes, a faulty NOx sensor can lead to poor fuel economy, increased emissions, and potential damage to the catalytic converter if left unresolved.

What tools are needed to troubleshoot the P116B code on a 2018 GMC Sierra?

Common tools include an OBDII scan tool, a multimeter for testing circuits, and possibly specialized tools for removing and replacing the NOx sensor.

Is code P116B covered under warranty for a 2018 GMC Sierra?

It depends on the vehicleâ€™s warranty terms. Emissions-related components like the NOx sensor may be covered under the federally mandated emissions warranty.