AutoCodes – Generic – P116B

P116B 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 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 654

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

What does this mean?

What are the Possible Causes of the DTC P116B?

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?

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 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 code?

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

Need Help with the Code?

Get the P116B code diagnosed by a professional: Find a repair shop in your area

Information for Specific Makes

P116B Buick — O2 Signal Circuit Low Voltage (NOx Sensor 1)
P116B Cadillac — O2 Signal Circuit Low Voltage (NOx Sensor 1)
P116B Chevrolet — O2 Signal Circuit Low Voltage (NOx Sensor 1)
P116B GMC — O2 Signal Circuit Low Voltage (NOx Sensor 1)

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 Code

1. What are the common symptoms of OBDII code P116B?

- Common symptoms include poor fuel efficiency, rough idling, reduced engine performance, and the illumination of the check engine light.

2. What does O2 Signal Circuit Low Voltage (NOx Sensor 1) mean in relation to code P116B?

- This code indicates that the O2 sensor circuit for the NOx Sensor 1 is detecting a lower voltage than expected, potentially signaling an issue with the sensor or its wiring.

3. What are some possible causes of OBDII code P116B?

- Causes can include a faulty NOx sensor, damaged wiring or connectors, a malfunctioning powertrain control module (PCM), or issues with the exhaust system.

4. How serious is OBDII code P116B?

- While the seriousness can vary, it's important to address this code promptly to prevent potential damage to the catalytic converter or other engine components.

5. Can I drive my vehicle with OBDII code P116B?

- It is generally not recommended to drive with this code present, as it can lead to poor engine performance and potential long-term damage if left unresolved.

6. How can I diagnose OBDII code P116B?

- Diagnosis typically involves using a scan tool to read the code, inspecting the NOx sensor and its connections, and conducting voltage tests to pinpoint the issue.

7. What are some repair tips for fixing OBDII code P116B?

- Repair tips may include replacing the NOx sensor, repairing damaged wiring, cleaning or replacing connectors, or updating the PCM software if necessary.

8. Can a DIY enthusiast fix OBDII code P116B?

- Depending on their skill level and access to tools, a DIY enthusiast may be able to address this code themselves, especially if it involves simple tasks like sensor replacement or wiring repair.

9. How much does it typically cost to repair OBDII code P116B at a mechanic?

- Repair costs can vary widely depending on the exact cause of the code, but they may range from $200 to $600 or more, including parts and labor.

10. How can I prevent OBDII code P116B from recurring?

- Regular maintenance, such as keeping up with sensor inspections and replacing worn components promptly, can help prevent the reoccurrence of this code.