AutoCodes – Chevrolet – P11B5 Chevrolet

P11B5 Chevrolet Code - HO2S Current Performance Bank 1 Sensor 2

Quick Answer

The reductant system uses two Nitrogen Oxide (NOx) sensors to monitor the amount of NOx in the engine's exhaust gas. Common causes include Faulty Heated Oxygen Sensor (HO2S), Heated Oxygen Sensor (HO2S) harness is open or shorted, Heated Oxygen Sensor (HO2S) 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: P11B5 Chevrolet indicates HO2S Current Performance Bank 1 Sensor 2.
Common causes: Common causes include Faulty Heated Oxygen Sensor (HO2S), Heated Oxygen Sensor (HO2S) harness is open or shorted, Heated Oxygen Sensor (HO2S) 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 3,864

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 Aug 28, 2019

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code P11B5 Chevrolet Description

The reductant system uses two Nitrogen Oxide (NOx) sensors to monitor the amount of NOx in the engine's exhaust gas. The first sensor is located at the outlet of the turbocharger and monitors the engine out NOx level. The second NOx sensor is located between the Selective Catalytic Reduction (SCR) and the Diesel Particulate Filter (DPF) and monitors NOx levels downstream of the SCR. The second NOx sensor also provides the Engine Control Module (ECM) with information on the exhaust oxygen level during DPF regeneration.
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 (DEF) or reductant added by varying the reductant injector duty cycle in response to changes in engine exhaust out 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.

OBDII Code P11B5 Chevrolet - HO2S Current Performance Bank 1 Sensor 2 - AutoCodes.com — P11B5 Chevrolet Code - HO2S Current Performance Bank 1 Sensor 2

What does this mean?

What are the Possible Causes of the DTC P11B5 Chevrolet?

Faulty Heated Oxygen Sensor (HO2S)
Heated Oxygen Sensor (HO2S) harness is open or shorted
Heated Oxygen Sensor (HO2S) circuit poor electrical connection

How to Fix the DTC P11B5 Chevrolet?

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 P11B5 Chevrolet 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 P11B5 Chevrolet code?

Need more information on how to fix the P11B5 Chevrolet 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 P11B5 Chevrolet Code

1. What are the common symptoms of OBDII code P11B5 in a Chevrolet related to HO2S Current Performance Bank 1 Sensor 2?

- Common symptoms include poor fuel economy, engine misfires, rough idling, and a noticeable decrease in overall engine performance.

2. What are the possible causes of OBDII code P11B5 in a Chevrolet?

- The code P11B5 can be triggered by issues such as a faulty oxygen sensor, wiring problems, exhaust leaks, or issues with the fuel system.

3. How can I diagnose the cause of OBDII code P11B5 in a Chevrolet?

- To diagnose the cause of the code, you can use an OBDII scanner to read the code and then perform a visual inspection of the oxygen sensor and its wiring. You may also need to check for exhaust leaks and perform a fuel system pressure test.

4. How can I repair OBDII code P11B5 in a Chevrolet?

- Repairing the code may involve replacing the oxygen sensor, repairing or replacing damaged wiring, fixing any exhaust leaks, or addressing issues with the fuel system. It's recommended to follow the manufacturer's diagnostic and repair procedures.

5. Can I continue driving my Chevrolet with OBDII code P11B5 present?

- It is not recommended to continue driving with the code present, as it can lead to further damage to the engine and emissions system. It's best to address the underlying issue as soon as possible.

6. Are there any DIY tips for fixing OBDII code P11B5 in a Chevrolet?

- While some DIY enthusiasts may attempt to replace the oxygen sensor themselves, it's important to have the proper tools and knowledge to do so correctly. If unsure, it's best to consult a professional mechanic.

7. How long does it typically take to repair OBDII code P11B5 in a Chevrolet?

- The repair time can vary depending on the exact cause of the code and the extent of the repairs needed. It can take anywhere from a few hours to a full day to diagnose and repair the issue.

8. Will resetting the OBDII code P11B5 in a Chevrolet make it go away permanently?

- Resetting the code may temporarily turn off the Check Engine Light, but if the underlying issue is not addressed, the code is likely to return. It's important to determine and fix the root cause of the problem.

9. Can a bad oxygen sensor cause OBDII code P11B5 in a Chevrolet?

- Yes, a faulty oxygen sensor, especially the one in Bank 1 Sensor 2, can trigger the P11B5 code due to incorrect readings affecting the air-fuel mixture and engine performance.

10. How much does it cost to repair OBDII code P11B5 in a Chevrolet at a dealership or a local mechanic?

- The cost of repairing OBDII code P11B5 can vary depending on the specific repairs needed, parts required, labor costs, and whether you go to a dealership or a local mechanic. It's recommended to get estimates from different sources before proceeding with the repair.