ECM assumes the ground circuit is open and shows P2251 when upstream O2 sensor is 1.49~1.53V and internal resistance gets high.
Item | Detecting Condition | Possible Cause |
DTC Strategy |
•
Circuit continuity check | 1. Poor connection 2. Open or short power/ground in signal circuit 3. S1 |
Enable Conditions |
•
Fuel cut condition | |
Threshold Value |
•
sensor voltage is higher than 4.8V | |
Diagnostic Time |
•
2 sec | |
MIL ON Condition |
•
2 driving cycle |
