Drive DTCP0171 – Engine is running lean (bank 1)
System too lean (Bank 1)
Fuel and air · generic OBD-II code
You can drive it, but take it easy and get it looked at soon – waiting usually makes the repair bigger.
Check this first
Look for a split intake hose or a loose oil cap or dipstick – unmetered air is the number one cause.
Lean running makes an engine hot. Fix it before it turns into misfires or a cooked catalytic converter.
What usually fixes it
In the order a good shop checks them. Typical total: $62–$844 at $130 an hour.
Vacuum or intake leak
Cracked hoses and leaking gaskets let in air the computer didn't measure.
Clean or replace the air flow sensor
A dirty sensor under-reads air, so the computer adds too little fuel.
Dirty fuel injectors or weak fuel pressure
Not enough fuel gives the same lean reading.
Upstream oxygen sensor
An aging sensor reports lean when the mixture is fine.
What the vehicle can tell you itself
A stored code is a headline, not the story. The vehicle also holds the conditions when it happened, how close the part is to the limit it fails at, what the fuel trims are doing, and whether the fault is still happening right now. Drive DTC reads all of it with a USB adapter and a Windows PC – and it can't change a single setting on the vehicle.
See what your vehicle says about P0171
Codes in plain English, what usually causes them, what the repair costs, and whether it's safe to drive.