OBD Operation Summary for Fiesta - MotorCraftService.com

Downstream HO2S12 Functional Check Operation:DTCs Sensor 2Monitor executionMonitor SequenceSensors OKMonitoring DurationP0140 HO2S12 No activityP2270 HO2S12 Signal Stuck LeanP2271 HO2S12 Signal Stuck Richonce per driving cycle for activity testNoneCKP, CMP, VVT, MAF, HO2S, HO2S heater, misfire, CPS, TPS, ECT, Fuelmonitorcontinuous until monitor completedTypical Downstream HO2S12 functional check entry conditions:Entry condition Minimum MaximumLambda set point for lean fault detection 0.80Integrated mass air flow outside of DFCOIntegrated mass air flow needed for open loop test to ensure thedesired lambda at downstream sensorIntegrated mass air flow in DFCOTime after start10 g120 s400 g50 gTypical Downstream HO2S12 functional check malfunction thresholds:P0140No activity, O2 sensor voltage stuck between 0.298 V and 0.550 VP2270Rich voltage could not be achieved, O2 sensor stuck lean: < 0.249 VP2271Lean voltage could not be achieved, O2 sensor stuck rich:> 0.555 VCONTINENTAL REVISED: SEPTEMBER 17, 2010 PAGE 55 OF 111