Conditions for Running the DTC: P2251

WARNING: This page is about a different car, the 2010 Chevrolet Cobalt. However, it is still accessible from the selected car via links, so may be relevant.

DTCs P0030, P0031, P0032 are not set.
The ignition voltage is between 10.7-18.1 volts.
The engine is running.
The HO2S 1 heater temperature has been within the normal range for more than 20 seconds.
HO2S 1 internal resistance is more than 950 ohms.
The following are true for more than 20 seconds.
- The HO2S 1 heater is ready.
- The engine is running.
- The ignition voltage is more than 11 volts.
DTC P2251 runs continuously when the above conditions are met.