Code Enable Criteria

WARNING: This page is about a different car, the 2002 Isuzu Trooper. However, it is still accessible from the selected car via links, so may be relevant.

Following conditions must be met for DTC diagnostic test to run:

No related DTCs.
Engine coolant temperature is 140°F (60°C) or more.
Engine is operating in closed loop.
Engine has been running at least one minute.
Canister purge duty cycle is 2 percent or more.
Engine speed is between 1500 and 3000 RPM.
Mass air flow is between 18 and 42 grams/sec.
Above conditions are present for a 3 second monitoring period.
Ninety seconds after closed loop operation has been enabled, Bank 1 HO2S No. 1 transition ratio between lean-to-rich and rich-to-lean is less than 0.44 or more than 3.8.