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p0491
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BMW · SUVs
Secondary Air Injection System Insufficient Flow Bank 1
Quick Answer
Error code P0491 on your BMW SUVs means: Secondary Air Injection System Insufficient Flow Bank 1. This is usually fixable — see the step-by-step guide below.
Affected Models
Applies to all models
X1 M35i 2024X1 xDrive28i 2024X3 M 2024X3 M40i 2024X3 xDrive30i 2024X5 M 2024X5 M60i 2024X5 xDrive40i 2024X5 xDrive50e 2024X6 M 2024X6 M60i 2024X6 xDrive40i 2024X7 M60i 2024X7 xDrive40i 2024iX M60 2024iX xDrive50 2024X1X3 MX3X5 MX5X6X7iX
Likely Causes
  1. Failed secondary air injection pump
  2. Carbon-clogged secondary air check valve
  3. Blocked air passages in the cylinder head
  4. Faulty secondary air pump relay or blown fuse
  5. Cracked or disconnected secondary air hoses
How to Fix It
1
Activate the secondary air pump with a scan tool and verify operation
2
Check the secondary air pump relay and fuse
3
Inspect secondary air check valves for carbon buildup
4
Inspect all secondary air hoses for cracks and proper connections
5
Replace the secondary air pump or check valves as needed
Pro Tip
This issue typically requires professional diagnosis. Attempting this fix without proper training could cause further problems.
Parts You May Need
Secondary air injection pump
Secondary air check valve
Secondary air pump relay
Secondary air hoses
Related Error Codes
P0171P0174P0300P0301P0335
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