Waveform Check
To speed up the warm-up of the oxygen sensor, the ECM energizes the sensor heating elements, except during cold starts and sudden accelerations.
The ECM uses signals from two sensors to keep the air-fuel ratio close to stoichiometric
Wiring check
With the ignition on, measure the voltage between the pins of the wired part of the connector and «weight».
Circuit under test | Rated voltage |
Contact 2 - «weight» | 0.45V |
Pin 4 - «weight» | B+ |
Contact 3 - «weight» | Approximately 3.5 V |
1. «Weight» sensor
2. Sensor signal
3. Heater control
4. Heater power
Heater check
Switch off the ignition and disconnect the sensor connector. Measure the resistance of the heating element with an ohmmeter. Rated value: 9.0 ohm (at 20°C).