Conditions for Running the DTC

WARNING: This page is about a different variant/trim than selected.

Before the ECM can report DTC P2251 failed, DTC P0030, P0031, P0032, and P0135 must run and pass.
The ignition 1 voltage is between 10.7-18.0 volts for more than 30 seconds.
The HO2S heater control is enabled.
The ECM has not commanded fuel cut-off for more than 2 seconds.
The HO2S heater is at operating temperature for more than 20 seconds.
The internal HO2S sensing element resistance is more than 570 ohms.
The calculated exhaust temperature is less than 900°C (1,652°F).
The ECM detects the internal HO2S signal voltage is between 1.47-1.53 volts.
DTC P2251 runs continuously once the above conditions are met for more than 10 seconds.