AutoCodes – MINI – P0491 MINI

P0491 MINI Code - AIR System Insufficient Flow Bank 1

Quick Answer

The AIR system refers to an emissions control system. Common causes include Secondary Air Injection Valve blocked, Faulty Secondary Air Injection Valve, Faulty Secondary Air Injection Pump. 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: P0491 MINI indicates AIR System Insufficient Flow Bank 1.
Common causes: Common causes include Secondary Air Injection Valve blocked, Faulty Secondary Air Injection Valve, Faulty Secondary Air Injection Pump.
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 1,679

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 Aug 11, 2020

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code P0491 MINI Description

The AIR system refers to an emissions control system. It is often called secondary air injection because air, more specifically oxygen, is injected into the exhaust manifold after startup. Vehicles start on a comparatively rich mixture to allow for smoother running conditions. However, this has a significant impact on exhaust gas emissions. A notable increase in hydrocarbon (HC) and carbon monoxide (CO) emissions are found under these rich start conditions. By injecting air into the exhaust manifold the CO and HC can be oxidized. This reaction increases the temperature within the exhaust and the exhaust gas after-treatment system i.e. catalytic converter can begin working earlier due to meeting its light-off temperature.
The system consists of an air pump, a one-way check valve and associated pipework. The system operates for a predetermined time after startup. Normally this duration is approximately three minutes, when cold.

OBDII Code P0491 MINI - AIR System Insufficient Flow Bank 1 - AutoCodes.com — P0491 MINI Code - AIR System Insufficient Flow Bank 1

What does this mean?

What are the Possible Causes of the DTC P0491 MINI?

Secondary Air Injection Valve blocked
Faulty Secondary Air Injection Valve
Faulty Secondary Air Injection Pump

How to Fix the DTC P0491 MINI?

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 P0491 MINI 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 P0491 MINI Code

1. What are common symptoms of OBDII code P0491 in a MINI vehicle?

- Common symptoms include decreased engine performance, rough idling, and the illumination of the check engine light.

2. What does the OBDII code P0491 "AIR System Insufficient Flow Bank 1" in a MINI indicate?

- This code indicates that there is not enough airflow in the secondary air injection system on bank 1 of the engine.

3. What are possible causes of OBDII code P0491 in a MINI?

- Potential causes include a faulty air pump, blocked or leaking air hoses, a malfunctioning check valve, or issues with the air injection system's electrical components.

4. How can I diagnose the cause of OBDII code P0491 in my MINI?

- Diagnosis typically involves visually inspecting the air injection system components, checking for leaks, testing the air pump and related components, and using a scan tool to monitor system operation.

5. Can I continue driving my MINI with OBDII code P0491 present?

- It is generally not recommended to continue driving with this code active, as it can lead to further damage to the engine and emissions system.

6. How can I repair OBDII code P0491 in my MINI?

- Repair may involve replacing a faulty air pump, repairing or replacing damaged air hoses, fixing a faulty check valve, or addressing any electrical issues in the air injection system.

7. Will resetting the check engine light resolve OBDII code P0491 in my MINI?

- Simply resetting the check engine light will not fix the underlying issue causing the code. It is important to diagnose and repair the root cause of the problem.

8. Can a DIY enthusiast fix OBDII code P0491 in a MINI?

- Depending on the level of expertise and access to tools, some DIY enthusiasts may be able to address this code themselves by following repair guides and using proper diagnostic equipment.

9. How much does it typically cost to repair OBDII code P0491 in a MINI at a professional auto repair shop?

- The cost of repair can vary depending on the specific issue, but it may range from $200 to $800 or more, including parts and labor.

10. Are there any preventative maintenance tips to avoid OBDII code P0491 in a MINI?

- Regularly inspecting and maintaining the air injection system components, ensuring proper engine air filter maintenance, and addressing any engine performance issues promptly can help prevent this code from occurring.