p0171
Moderate
GMC · SUVs
System Too Lean (Bank 1)
Quick Answer
Error code P0171 on your GMC SUVs means: System Too Lean (Bank 1). This is usually fixable — see the step-by-step guide below.
Affected Models
Likely Causes
How to Fix It
1
Connect diagnostic scanner to OBD-II port
2
Read and record all freeze frame data
3
Check for vacuum leaks visually
4
Test oxygen sensors with multimeter
5
Inspect and replace air filter if needed
Pro Tip
This fix requires some technical knowledge. If you're unsure about any step, consider contacting support or a qualified technician.
Parts You May Need
Oxygen sensor
Air filter
Spark plugs
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