P0131: O2 Sensor Circuit Low Voltage Bank 1 Sensor 1
A generic powertrain (engine and transmission) trouble code, same meaning on every brand.
Yes - expect worse fuel economy until repaired.
Symptoms
- Check engine light
- Reduced economy, occasional rough idle
Likely causes, most common first
- Aged upstream O2 sensor biased low
- Exhaust leak near the sensor pulling in air
- Wiring chafe shorting the signal
- A genuinely lean condition the sensor is honestly reporting
Read P0131 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
P0131 flags the bank 1 upstream oxygen sensor for reading persistently low voltage - either the sensor is failing, or it is truthfully reporting a lean exhaust stream. That distinction is the whole diagnosis.
A scan tool answers it quickly: if fuel trims are heavily positive, the engine really is lean and the sensor is the messenger, not the fault - go hunt the lean cause. If trims are normal, the sensor itself has drifted. Replacing O2 sensors on trim data rather than reflex saves a lot of misdirected parts money.
Repair options and cost
Typical US independent-shop ranges, parts and labor. Dealers run higher; regional labor rates vary.
Owner reports mentioning P0131
“While driving 60 MPH on the highway my car started stuttering then lost all power. It threw 3 codes P0131, P2097 and P0171. I have spent over $1,000.00 and a month later they tell me it was my intake bolts that were loose. They replaced every part PCV valve, MAF sensor, O2 sensor and car still wouldn't run right. PLEASE address this issue as that is UNSAFE for a car to just stop on the highway.”2014 Chevrolet Malibu · Mar 2024 · 167,611 mi
“When starting my vehicle this morning my check engine light was on and my car was sputtering whenot sitting at a light or idling. Went to repair shop for duagnosis. Came up with several codes. P0171- system 2 lean bank 1. Second code p0106 manifold absolute oressure/barometer sensor, p0131 02 circuit low voltage be s1. P1101 intake air flow system performance low. Tcs on. I need to know if this covered by the vehicle warranty.”2015 Chevrolet Cruze · Jan 2019 · 62,100 mi
“Car starts bucking, check engine light comes on, white smoke blowing out exhaust, eventually car dies. Dealer states, 02 sensor in bank one failed. Car has been back to dealer for same failure 5 times in a 4 month period. P0131, p1133, p0300 and p0171. Purchased vehicle june 20, 2008 fist issue was july 15, 2008. Vehicle was purchased as a gm certified used vehicle with less then 25000 miles on it. Gm case # 10447543. Car was last in the shop 11/2008 and has been put in my garage for the winter. Will not know if problem has been resolved until spring. *tr”2006 Chevrolet Corvette · Nov 2008 · 21,113 mi
Cars that report P0131 most often
Based on mentions of this code in NHTSA owner complaints.
Frequently asked questions
Can I drive with P0131?
Yes - expect worse fuel economy until repaired.
How much does it cost to fix P0131?
Typical US repair costs range from $80 for the simplest fix (upstream o2 sensor) to $450 in the worst case. The right number depends on which cause your car has - see the causes list.
Definition per SAE J2012 standard nomenclature. Symptoms, causes and costs are editorial guidance - always confirm with a diagnosis of your specific vehicle.