Crossover Counts (Numeric Display)

The O2 sensor voltage fluctuates around a threshold voltage: the value of which is stored in the PROM. A counter within the ECM "counts" the number of times that actual oxygen sensor voltage crosses this threshold to indicate how fast the sensor is oscillating. The crossover count is the value representing the number of times that the sensor value crosses this threshold in 1.25 seconds. A higher crossover count number indicates a more closely air/fuel mixture ratio.