P2197: O2 Sensor Signal Biased/Stuck Lean Bank 2 Sensor 1
A generic powertrain (engine and transmission) trouble code, same meaning on every brand.
Yes - economy suffers and the mixture may drift.
Symptoms
- Poor fuel economy
- Uneven running
- Fuel smell from the exhaust
Likely causes, most common first
- Bank 2 upstream sensor biased lean
- Exhaust leak upstream of the sensor
- Sensor contamination
- Ground or wiring fault
Read P2197 yourself before paying for diagnosis
A basic Bluetooth OBD-II scanner ($20-40) plugs into the port under the dashboard and shows this code with live sensor data on your phone - useful both for confirming the fix and for talking to a shop from an informed position.
What is going on and how it gets diagnosed
P2197 is the bank 2 version of a lean-biased upstream sensor. On V engines an exhaust manifold crack is a frequent cause and one that is easy to miss, because the crack often closes as the metal expands and only leaks when the engine is cold.
Listening at a cold start is the practical test. A ticking that fades within a minute or two as the manifold warms is the sound of a crack sealing itself, and it explains a lean-biased sensor without any fault in the sensor at all.
Repair options and cost
Typical US independent-shop ranges, parts and labor. Dealers run higher; regional labor rates vary.
Owner reports mentioning P2197
“This is in reference to Field Service Action 13N02 with codes P2195 and P2197. There was an extended warranty, but I never knew that as I bought the vehicle pre-owned. I am a college student and the vehicle poses a danger as I am not able to stop every time. I called the local Ford dealership, and without even looking at the vehicle. He said, yes we know about the issue, but it's to late for you to have it repaired for free. I am filing a complaint with with the Wyoming Attorney General as well, and looking into a civil action. I want to make sure I document everything in case there is a serious injury or death.”2011 Ford Edge · Jul 2025
Cars that report P2197 most often
Based on mentions of this code in NHTSA owner complaints.
Frequently asked questions
Can I drive with P2197?
Yes - economy suffers and the mixture may drift.
How much does it cost to fix P2197?
Typical US repair costs range from $80 for the simplest fix (upstream oxygen sensor) to $600 in the worst case. The right number depends on which cause your car has - see the causes list.
Related codes
The codes closest to P2197. They often appear together, and telling them apart is usually what narrows the diagnosis.
Definition per SAE J2012 standard nomenclature. Symptoms, causes and costs are editorial guidance - always confirm with a diagnosis of your specific vehicle.