The downstream heated oxygen sensor (HO2S) is forced rich and lean and monitored by the ECM. This DTC sets when the ECM does not detect the output of the HO2S in a calibrated amount of time.
Item | Detecting Condition | Possible Cause | |
Case 1 | DTC Strategy |
•
No signal activity | 1. Poor connection 2. Short to Power in signal circuit 3. HO2S(S1/S2) 4. ECM 5. Exhaust leaks |
Enable Conditions |
•
Battery voltage > 10.7 V
•
Lambda = 1.1 for 9 sec. | ||
Threshold Value |
•
Downstream O2S voltage > 0.65 V | ||
Case 2 | DTC Strategy |
•
Oscillation check : Test condition is checked at every 500 sec after oscillation check is performed | |
Enable Conditions |
•
Downstream O2S voltage > 0.65 V for 100 sec.
•
Fuel system status = Closed loop
•
1120 rpm < Engine speed < 3000 rpm
•
20 % < Engine load < 83 %
•
Mass airflow > 20 kg/h
•
EGT around downstream O2S > 700 ℃(1292 °F) or O2S heater voltage > 9.2 V or 0.5 < Downstream O2S voltage < 0.4 | ||
Threshold Value |
•
If All secondary conditions met then Fuel system open loop control Lambda = 1.1 for 9 sec. | ||
Diagnostic Time |
•
10 sec. | ||
MIL ON Condition |
•
2 Driving Cycles | ||
