Conditions for Running the DTC

Condition 1

• Before the ECM can report DTC P2237 or P2240 failed, DTCs P0101, P0121, P0122, P0123, P0133, P0135, P0153, P0155, P0221, P0222, P0223, P0336, and P0338 must run and pass.
• The engine is operating in closed loop.
• The HO2S heater is at operating temperature.
• The ECM is commanding the lambda more than 1.03 or less than 0.97.
• DTC P2237 and P2240 run continuously once the above conditions are met.

Condition 2

• Before the ECM can report DTC P2237 or P2240 failed, DTCs P0101, P0121, P0122, P0123, P0221, P0222, P0223, P0336, and P0338 must run and pass.
• The engine is operating in closed loop.
• The HO2S heater is at operating temperature.
• The ECM detects the internal HO2S signal voltage is between 1.48-1.52 volts.
• The ECM is commanding the lambda rich and then lean periodically with a change of more than 2 percent.
• DTC P2237 and P2240 run continuously once the above conditions are met.

Condition 3

• The HO2S heater is at operating temperature.
• DTCs P0133 and P0153 ran and completed.
• DTC P2237 and P2240 run continuously once the above conditions are met.