To read the output of the oxygen sensor, connect terminal T or TE1 with terminal El, with the idle contact off. Then measure the voltage at the VF or VF1 terminal. (The output from this terminal is not the actual signal that is output by the oxygen sensor, but a signal that has been digitalized by the ECU for easier reading.) This signal is 5V when the input signal from the oxygen sensor is higher than the comparison voltage set by the ECU, and is 0V when the input signal is lower than the comparison voltage or during an open-loop operation.
- Oxygen sensor output signal: T or TE1 terminal on, idle contact off