P0491
AIR System Insufficient Flow Bank 1
P0491 is an OBD-II diagnostic trouble code meaning: AIR System Insufficient Flow Bank 1. Common causes: clogged air channels of the secondary air system, secondary air system valve malfunction. Estimated repair cost: $56–167.
Symptoms
- Increased emissions
- Unstable engine operation at idle
- Check Engine light comes on
Causes
- Clogged air channels of the secondary air system
- Secondary air system valve malfunction
- Problems with the secondary air pump
- Open or short circuit in wiring harness
- Air pressure sensor malfunction
How to Fix
- Check the condition of the air channels of the secondary air system
- Check the operation of the secondary air system valve
- Check the secondary air system pump
- Check wiring harness for damage
- Check air pressure sensor
Related codes
Error P0491 by Vehicle Brand
FAQ
What does the P0491 code mean?
P0491 is an OBD-II diagnostic trouble code that indicates: AIR System Insufficient Flow Bank 1
What causes a P0491 error code?
The most common causes of P0491 include: Clogged air channels of the secondary air system; Secondary air system valve malfunction; Problems with the secondary air pump; Open or short circuit in wiring harness.
How do I fix a P0491 diagnostic trouble code?
To fix P0491: Check the condition of the air channels of the secondary air system. Check the operation of the secondary air system valve. Check the secondary air system pump. For a complete diagnosis, use an OBD-II scanner.
Is it safe to drive with P0491?
Limited driving only, diagnose soon
How much does it cost to fix P0491?
The estimated repair cost for P0491 is $56–167. Actual cost depends on your vehicle, location, and labor rates.
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