P0131 - OXYGEN SENSOR CIRCUIT LOW VOLTAGE (B1 S1)

The P0131 diagnostic code indicates that the voltage remained low for more than 2 minutes. The PCM (Powertrain Control Module) interprets this voltage as a low voltage condition, and that is where the check engine light activates on your board.

Note: This Sensor (02 Oxygen Lambda Sensor) is located near the Catalytic Converter.

Generally for code P0131 there are no visible symptoms, except for the following:

• The Check Engine Service light is on.
• It can have a high fuel consumption.
• Excessive smoke from the exhaust pipe.

• One of the main causes of this DTC code P0131 is that the Oxygen Sensor (O2 LAMBDA) is defective.
• The Oxygen Sensor Circuit (O2 LAMBDA) may be shorted.
• The circuit may be open at the Oxygen Sensor signal (O2).

• Clean the Oxygen Sensor (O2).
• Mount the sensor on a PCM test bench and verify that the signal in volts is correct.
• If the Oxygen Sensor (O2) circuit is short or open, repair it.
• Verify by reading the data line / live with an advanced automotive scanner and note the readings in volts, both for vehicle in brand, and in idle.
• Replace the Oxygen Sensor (02) defective.

Note: The normal ratio of this sensor should indicate 14/7 parts of air per 1 stoichiometric fuel.

Remember that this sensor is very important for the protection of the environment under SAE standards that regulate the automotive market worldwide.