ECM/PCM 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 |
•
Reference Ground Circuit Open check | 1. Poor connection 2. Open or short power/ground in signal circuit 3. Upstream O2S |
Enable Conditions |
•
Internal Resist Value > 950 Ω | |
Threshold Value |
•
Sensor voltage is at 1.47~1.53V | |
Diagnostic Time |
•
- | |
MIL ON Condition |
•
2 Driving Cycle |
