P0131
O2 Sensor Circuit Low Voltage (Bank 1 Sensor 1)
System: Emissions
Severity: medium
What does P0131 mean?
The DTC P0131 (O2 Sensor Circuit Low Voltage (Bank 1 Sensor 1)) is a fault code stored by the ECU when it detects a O2 B1S1 low condition in the emissions subsystem. It is commonly seen on European and Asian vehicles using Bosch, Continental, Siemens or Denso ECUs.
Common causes of P0131
- Lean condition (vacuum leak)
- Failed O2 sensor
- Short to ground in signal wire
- Exhaust leak before sensor
How to fix P0131
Smoke test for vacuum leaks first — most P0131s are vac leaks, not bad sensors.
Tuning approach with DaVinci Deluxe
For P0131, DaVinci Deluxe offers the following ECU map adjustments and software solutions:
- Fuel trim recalibrate
- Lambda target adjust
- Lean cruise enable
Need to fix P0131 on your ECU?
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