AutoCodes – Generic – P126F

P126F Code - Nitrogen Oxide Sensor Trailing Throttle Check Linear Lambda Signal Too Rich

Quick Answer

The Engine Control Module (ECM) monitors the Nitrogen Oxide (NOx) Sensor. Common causes include Faulty Nitrogen Oxide (NOx) Sensor, Nitrogen Oxide (NOx) Sensor harness is open or shorted, Nitrogen Oxide (NOx) 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: P126F indicates Nitrogen Oxide Sensor Trailing Throttle Check Linear Lambda Signal Too Rich.
Common causes: Common causes include Faulty Nitrogen Oxide (NOx) Sensor, Nitrogen Oxide (NOx) Sensor harness is open or shorted, Nitrogen Oxide (NOx) 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 3,224

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 Jul 02, 2020

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code P126F Description

The Engine Control Module (ECM) monitors the Nitrogen Oxide (NOx) Sensor. The ECM sets the OBDII code when the Nitrogen Oxide (NOx) Sensor is not to factory specifications.

OBDII Code P126F - Nitrogen Oxide Sensor Trailing Throttle Check Linear Lambda Signal Too Rich - AutoCodes.com — P126F Code - Nitrogen Oxide Sensor Trailing Throttle Check Linear Lambda Signal Too Rich

What does this mean?

What are the Possible Causes of the DTC P126F?

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

How to Fix the DTC P126F?

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 P126F 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 P126F code?

Need more information on how to fix the P126F code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the P126F code diagnosed by a professional: Find a repair shop in your area

Information for Specific Makes

P126F BMW — Nitrogen Oxide Sensor Trailing Throttle Check Linear Lambda Signal Too Rich
P126F Ford — Fuel Injector 6 Input Circuit Malfunction
P126F MINI — Nitrogen Oxide Sensor Trailing Throttle Check Linear Lambda Signal Too Rich

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 P126F Code

1. What are common symptoms of OBDII code P126F?

- Common symptoms include reduced engine performance, rough idling, increased fuel consumption, and possible engine misfires.

2. What does the OBDII code P126F indicate?

- OBDII code P126F indicates that the nitrogen oxide sensor trailing throttle check linear lambda signal is reading too rich, meaning there is an imbalance in the air-fuel mixture.

3. What are possible causes of OBDII code P126F?

- Possible causes include a faulty nitrogen oxide sensor, issues with the fuel system, vacuum leaks, a malfunctioning catalytic converter, or problems with the engine's air intake system.

4. How can I diagnose the cause of OBDII code P126F?

- Diagnosing the cause of P126F may require using a scan tool to read the code, conducting a visual inspection for any obvious issues, checking the nitrogen oxide sensor's wiring and connections, and performing a thorough inspection of the fuel system.

5. Can I drive my vehicle with OBDII code P126F?

- It is not recommended to drive your vehicle with OBDII code P126F as it can lead to further damage to the engine and emission systems. It is best to address the issue promptly.

6. How can I repair OBDII code P126F?

- Repairing P126F may involve replacing the nitrogen oxide sensor, addressing any fuel system issues, fixing vacuum leaks, replacing the catalytic converter if necessary, and ensuring the air intake system is functioning correctly.

7. Will resetting the OBDII code P126F make it go away permanently?

- Simply resetting the code may temporarily clear the check engine light, but if the underlying issue causing P126F is not addressed, the code is likely to reappear.

8. Can a DIY enthusiast fix OBDII code P126F?

- Depending on your mechanical skills and access to tools, some DIY enthusiasts may be able to address the root cause of P126F, especially if it involves sensor replacement or basic troubleshooting. However, more complex issues may require professional help.

9. How much does it typically cost to repair OBDII code P126F?

- The cost of repairing P126F can vary widely depending on the cause of the issue, the parts needed, and whether you choose to do the repairs yourself or take your vehicle to a mechanic. Costs can range from a few hundred dollars to over a thousand dollars.

10. How urgent is it to fix OBDII code P126F?

- It is recommended to address OBDII code P126F as soon as possible to prevent potential damage to the engine, catalytic converter, and emission systems. Driving with this code unresolved can also impact fuel efficiency and overall vehicle performance.