1/1 O2 Sensor Shorted to Ground (OBD II)
1/1 UPSTREAMName of Code:
O2S Voltage Shorted To Ground
When Monitored:
With engine coolant temperature above 170 ° F on the previous key on, after a cold start, engine coolant below, 98 ° F and ambient/battery sensor reading within 27 ° F of engine coolant.
Set Condition:
The oxygen sensor signal voltage is below 0.156 voltage for 25 seconds after starting engine.
Theory of Operation:
The oxygen sensor is a voltage generating device. The PCM receives exhaust gas information from this O2 sensor. The sensor detects exhaust gas content by a galvanic reaction with in the sensor that produces a voltage. After measuring the amount of oxygen in the exhaust gases, the oxygen sensor tells the PCM how well its output signals are controlling the air/fuel ratio. Variations in the signal from this O2 sensor serve as air/fuel ratio indicators. Changes in the sensor signal occur because the air/fuel ratio is constantly changing. When oxygen content is low (rich mixture), the voltage signal will us high, approximately 10 volt
Possible Causes:
- Sensor output wire shorted to ground
- Dirty/Wet connection causing voltage tracking in connector
- O2 sensor failure
- Powertrain control module failure
- Connector terminals
- Connector wires