P0131 on Your 2022 Buick Enclave
Code P0131 on your 2022 Buick Enclave indicates the Bank 1 Sensor 1 oxygen sensor is reading below the ECM's expected voltage threshold. The 2022 Enclave uses the 3.6L V6 (LGX) producing 310 hp, shared across many GM vehicles. This naturally aspirated V6 is mounted transversely, with Bank 1 being the rear bank (firewall side). Sensor 1 is the upstream O2 sensor positioned before the catalytic converter on the Bank 1 side.
Symptoms
- Check engine light on
- Reduced fuel economy on a three-row SUV where efficiency matters
- Subtle rough idle
- Mild hesitation during acceleration
- Possible rich exhaust smell
Common Causes on the Enclave
1. O2 Sensor Wear
The 3.6L V6's rear bank exhaust manifold runs hot, and the upstream sensor at that location endures significant thermal cycling. Over time, the sensor's internal zirconia element loses reactivity and defaults to a low-voltage reading. With a 2022 model potentially at 25,000–50,000 miles, this is the most common P0131 cause.
2. Connector Corrosion
The Enclave is a family SUV that sees all weather conditions. The rear bank O2 sensor connector sits in an area prone to heat and moisture accumulation. Road salt exposure, especially in northern climates, can corrode the connector pins and introduce resistance on the signal wire.
3. Exhaust Manifold Leak
The 3.6L V6's exhaust manifold gaskets can degrade from thermal cycling. A leak at the Bank 1 (rear) manifold introduces ambient air past the O2 sensor, creating a false lean reading. Listen for a ticking sound at cold start that fades as the engine warms.
4. Lean Fuel Condition
A genuine lean condition from a vacuum leak at the intake manifold, a failing fuel pump, or dirty fuel injectors can cause accurate lean readings. P0171 alongside P0131 confirms a real lean condition rather than a sensor fault.
Diagnostic Steps
- Scan all codes — check for P0171 companion code.
- Monitor Bank 1 Sensor 1 voltage with a scan tool. Should oscillate 0.1V to 0.9V at warm idle.
- Compare Bank 1 and Bank 2 upstream sensor readings for asymmetry.
- Inspect the rear bank sensor connector for corrosion or moisture.
- Check the rear bank exhaust manifold for leak signs (soot marks, ticking).
- Review fuel trims — LTFT above +15% on Bank 1 indicates genuine lean operation.
Repair Costs
An OE-spec upstream O2 sensor for the Enclave's 3.6L: $60–$150. Shop labor: $100–$200. Total: $160–$350. Exhaust manifold gasket repair: $200–$500. The 2022 Enclave should still be under the 8-year/80,000-mile federal emissions warranty for the O2 sensor.
Priority
Fix within two weeks. The Enclave is a family vehicle where reliability and efficiency matter. Under emissions warranty, this may be a free repair at your Buick dealer.