P00D5 HO2S Sensor Correlation Bank 1 Sensor 1/Bank 1 Sensor 2

During fuel cut-off on overrun the exhaust gas is pure air, so the oxygen sensors before and behind the catalytic converter must both report the same lean value. A documented method averages and normalises the signals of both sensors during fuel cut-off and sets the code when they differ by more than a limit; it runs once per drive cycle and needs several overrun phases. The code points to one of the sensors having drifted, not to the catalytic converter. The manufacturer documenting it uses wide-band sensors in both positions.

Likely causes

Symptoms

• Check engine light on
• Usually no noticeable drivability problem
• Catalyst readiness may stay incomplete

Repair estimate

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

Related codes

References: law.cornell.edu, estimateca.mymitchell.com, en.wikipedia.org.