Conditions for Running the DTC

WARNING: This page is about a different car, the 2009 Saturn Vue. However, it is still accessible from the selected car via links, so may be relevant.

Before the ECM can report DTC P2251 or P2254 failed, DTC P0030, P0031, P0032, P0050, P0051, P0052, P0135 and P0155 must run and pass.
The ignition voltage is between 11-18 volts for greater than 30 seconds.
The HO2S 1 heater control is enabled.
The ECM has not commanded fuel cut-off for greater than 2 seconds.
The HO2S 1 heater is at operating temperature for greater than 20 seconds.
The internal HO2S 1 sensing element resistance is greater than 570 Ω.
The calculated exhaust temperature is colder than 900°C (1,652°F).
The ECM detects the internal HO2S 1 signal voltage is between 1.47-1.53 volts.
DTC P2251 and P2254 run continuously once the above conditions are met for greater than 10 seconds.