What Does P0131 Mean on Your 2020 Nissan Murano?
The P0131 code on your 2020 Murano indicates the Bank 1 Sensor 1 upstream O2 sensor is reading consistently low voltage. The 2020 Murano is the third generation (Z52) powered by the VQ35DE 3.5L V6 with Xtronic CVT. On the transverse-mounted VQ35DE in the Murano, Bank 1 is the front cylinder bank (facing the radiator and front bumper). Sensor 1 is the upstream O2 sensor in the front exhaust manifold before the catalytic converter.
The sensor should generate a voltage oscillating between 0.1V and 0.9V. A sustained signal below 0.2V triggers P0131. The Nissan OEM part for the front bank upstream sensor is typically 226A0-JA10C.
Symptoms to Watch For
- Check engine light on
- Fuel economy decrease from the expected 20/28 MPG
- Rough or uneven idle
- Sluggish acceleration response
- CVT may feel less smooth during moderate acceleration
Most Likely Causes on the 2020 Murano
1. Worn O2 Sensor
With 4-6 years of service and potentially 50,000-80,000 miles, the 2020 Murano's upstream sensor is in the typical failure range. The VQ35DE in the Murano is a well-proven engine, but the O2 sensor's zirconia element degrades from years of exhaust heat exposure. The Murano tends to be driven in mixed city/highway conditions that create frequent heat cycling — the engine heats up, the owner parks for errands, then starts again — which is harder on sensors than sustained highway driving.
2. Wiring Harness Corrosion
The Murano's crossover body style exposes the underbody to road spray and salt. The front bank O2 sensor connector on the 2020 Murano sits in the engine bay but the harness runs through areas where moisture can accumulate. After several years in northern climates, connector pin corrosion is a common finding. Look for green or white deposits on the four-wire connector pins.
3. Exhaust Manifold Leak
The front exhaust manifold on the VQ35DE can develop gasket leaks from thermal cycling. The manifold-to-head joint is the most common leak point. An exhaust leak here allows ambient air to dilute the exhaust gases before reaching the sensor, causing a lean reading. Listen for ticking or tapping from the front of the engine during cold starts.
4. Lean Fuel Condition
Vacuum leaks from aged intake gaskets, cracked PCV hoses, or a stuck-open EVAP purge valve can cause the Murano to run lean. The O2 sensor is accurately reporting the lean condition. Check fuel trims with a scan tool — long-term fuel trim above +10% on Bank 1 suggests a genuine lean issue. The CVT may also behave differently when the ECM modifies torque output to compensate for lean operation.
How to Diagnose
Use a scan tool to monitor Bank 1 Sensor 1 voltage at warm idle. A working sensor oscillates between 0.1V and 0.9V several times per second. If stuck below 0.2V, test the sensor's heater circuit (3-15 ohms resistance) and verify heater power.
On the Murano, the front bank sensor is accessible from the top of the engine bay. Look at the front exhaust manifold between the engine and the radiator. A 22mm O2 sensor socket with a ratchet provides good leverage. Apply penetrating oil before removal if the sensor has been in place for several years.
Repair Costs
- O2 sensor replacement: $150–$350
- Wiring or connector repair: $80–$220
- Front exhaust manifold gasket: $250–$500
- Vacuum leak or fuel system repair: $150–$400
Can You Keep Driving?
Yes, the 2020 Murano will drive safely with P0131. The ECM uses open-loop fueling as a fallback. The CVT will continue to function, though acceleration may feel slightly less refined. Fix the issue within a couple of weeks to avoid catalytic converter stress and maintain fuel efficiency.