P2A00 Citroen Oxygen (O2) Sensor Circuit Range / Performance (Bank 1 – Sensor 1)

Possible causes

– Faulty Air fuel Ratio (A/F) Bank 1 Sensor 1
– Air fuel Ratio (A/F) Bank 1 Sensor 1 harness is open or shorted
– Air fuel Ratio (A/F) Bank 1 Sensor 1 circuit poor electrical connection
– Fuel pressure
– Fuel injector
– Intake air leaks

What about the obd code?

The P2A00 Citroen Code is set when A/F sensor output voltage change value is below regular value against fuel trim change value.

Symptoms

– Engine Light ON (or Service Engine Soon Warning Light)

P2a00 Description

The Air-Fuel ratio (A/F) sensor varies its output voltage in proportion to the air-fuel ratio. Based on the output voltage, the ECM determines if the air-fuel ratio is RICH or LEAN and adjusts the stoichiometric air-fuel ratio. The ECM also checks the fuel injection volume compensation value to check if the A/F sensor is deteriorating or not. A/F sensor response deterioration is determined by the ratio of the A/F sensor output voltage variation and fuel trim variation.