AutoCodes – Audi – P0140 Audi

P0140 Audi Code - HO2S12 Sensor Circuit No Activity Detected

Quick Answer

The heated oxygen sensor 2 (HO2S), after three way catalyst (manifold), monitors the oxygen level in the exhaust gas on each bank. Common causes include Faulty Rear Heated Oxygen Sensor Bank 1, Rear Heated Oxygen Sensor Bank 1 harness is open or shorted, Rear Heated Oxygen Sensor Bank 1 circuit poor electrical connection. Severity is Moderate - service should be scheduled soon. The vehicle may still be drivable for short trips if it runs normally, but avoid hard driving and repair it soon.

What it means: P0140 Audi indicates HO2S12 Sensor Circuit No Activity Detected.
Common causes: Common causes include Faulty Rear Heated Oxygen Sensor Bank 1, Rear Heated Oxygen Sensor Bank 1 harness is open or shorted, Rear Heated Oxygen Sensor Bank 1 circuit poor electrical connection.
Severity: Moderate - service should be scheduled soon.
Can I drive?: The vehicle may still be drivable for short trips if it runs normally, but avoid hard driving and repair it soon.

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Code Popularity 18,012

How popular is this code, among other codes? Low

Repair Importance Level

Moderate (Service soon) (2 / 3)

Repair Difficulty Level

Intermediate (2 / 3)

What is this?

Table of contents Created and updated by William Orellana on Apr 12, 2019

Description
Possible Causes
How To Fix
Tech Notes
Cost to Diagnose
FAQs
Comments
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Code P0140 Audi Description

The heated oxygen sensor 2 (HO2S), after three way catalyst (manifold), monitors the oxygen level in the exhaust gas on each bank. For optimum catalyst operation, the air fuel mixture (air-fuel ratio) must be maintained near the ideal stoichiometric ratio. The HO2S output voltage changes suddenly in the vicinity of the stoichiometric ratio. The Engine Control Module (ECM) adjusts the fuel injection time so that the air-fuel ratio is nearly stoichiometric. The HO2S generates a voltage between 0.1 and 0.9 V in response to oxygen in the exhaust gas. If the oxygen in the exhaust gas increases, the air-fuel ratio becomes Lean. The ECM interprets Lean when the HO2S voltage is below 0.45 V. If the oxygen in the exhaust gas decreases, the air-fuel ratio becomes Rich. The ECM interprets Rich when the HO2S voltage is above 0.45 V.

OBDII Code P0140 Audi - HO2S12 Sensor Circuit No Activity Detected - AutoCodes.com — P0140 Audi Code - HO2S12 Sensor Circuit No Activity Detected

What does this mean?

What are the Possible Causes of the DTC P0140 Audi?

Faulty Rear Heated Oxygen Sensor Bank 1
Rear Heated Oxygen Sensor Bank 1 harness is open or shorted
Rear Heated Oxygen Sensor Bank 1 circuit poor electrical connection
Inappropriate fuel pressure
Faulty fuel injectors
Intake air leaks may be faulty
Exhaust gas leaks

How to Fix the DTC P0140 Audi?

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 does this mean?

Code Tech Notes

Replacing the Rear Heated Oxygen Sensor Bank 1 usually takes care of the problem.

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P0140 Audi 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.

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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 P0140 Audi Code

1. What does the OBDII code P0140 for an Audi indicate?

The P0140 code specifically relates to the HO2S12 sensor circuit detecting no activity.

2. What are the common symptoms of a P0140 code in an Audi?

Common symptoms include poor fuel economy, engine misfires, rough idling, and potential stalling.

3. What are the possible causes of a P0140 code in an Audi?

Potential causes include a faulty HO2S12 sensor, wiring issues in the sensor circuit, exhaust system leaks, or a malfunctioning PCM.

4. How can I diagnose the cause of a P0140 code in my Audi?

Diagnosing the issue involves checking the sensor's wiring for damage, inspecting the sensor for physical defects, and using a scan tool to monitor sensor data.

5. Can I drive my Audi with a P0140 code present?

It is not recommended to drive with a P0140 code, as it can lead to further damage and potential safety hazards.

6. How can I repair a P0140 code in my Audi?

Repairing the issue may involve replacing the HO2S12 sensor, repairing damaged wiring, fixing exhaust leaks, or resetting the PCM.

7. Is it possible to prevent the recurrence of a P0140 code in my Audi?

Regular maintenance, including checking and replacing oxygen sensors as needed, can help prevent the recurrence of a P0140 code.

8. Are there any DIY tips for addressing a P0140 code in an Audi?

While some basic diagnostic steps can be taken at home, addressing a P0140 code may require specialized tools and knowledge, making professional assistance advisable.

9. How much does it typically cost to repair a P0140 code in an Audi?

Repair costs for a P0140 code can vary depending on the exact cause of the issue, but it's advisable to budget for sensor replacement or potential wiring repairs.

10. Can a P0140 code in an Audi affect emissions and overall vehicle performance?

Yes, a P0140 code can impact emissions output and vehicle performance, making it essential to address the issue promptly to maintain optimal engine function.