Titania Oxygen Sensor Testing: Operation
A 5-volt reference voltage signal is sent through a fixed resistor internal to Renix ECU. See Fig 1 . The output from the resistor is monitored by ECU. The reference voltage is connected to input of O2 sensor. Unlike zirconia O2 sensors, when oxygen content is low (rich mixture), voltage signal is less than 2.5 volts. When oxygen content is high (lean mixture), voltage signal is more than 2.5 volts.
Titania O2 sensors are heated. Voltage is supplied to heating element by a PCM-controlled relay. Titania O2 sensor heating element resistance is 5-7 ohms. Titania O2 sensor output should be similar (response time, cross counts), except for voltage. Instead of 0-1 volt, low voltage equals lean (Zirconia), Titania O2 sensor voltages are 1-5 volts, high voltage equals lean.