The most obvious phenomenon of a bad front oxygen sensor is as follows:
The fault phenomenon of a bad front oxygen sensor:
(1) The engine malfunction lamp lights up.
(2) The engine idles and shakes.
(3) Gasoline fuel consumption increases.
(4) Unqualified exhaust emissions.
(5) Black smoke from the exhaust pipe.
Front oxygen sensor bad fault causes:
(1) Front oxygen sensor aging.
(2) poisoning of the front oxygen sensor (lead poisoning, silicon poisoning, phosphorus poisoning).
(3) Damaged front oxygen sensor.
(4) Front oxygen sensor line break or short circuit.
(5) Engine control unit failure.
Bad front oxygen sensor fault analysis and troubleshooting:
Use the computer diagnostic instrument to read the engine fault code, observe whether there is a fault of the front oxygen sensor, and confirm whether it is a temporary or permanent fault:
1, read the data stream of the front oxygen sensor, the voltage in the 0.1 ~ 1V between the constant changes, changes in the The number of times 10s is more than 8 times. If the voltage changes between 0.1~0.5V, it means that the mixture is too thin; if the voltage changes between 0.5~1V, it means that the mixture is too thick; if the voltage does not move between 0.4~0.5V, it means that the oxygen sensor is damaged.
2, check the oxygen sensor resistance, when the engine temperature reaches normal, unplug the oxygen sensor wire connector, with a resistance meter to detect the resistance value between the pressure sensor terminals, the resistance value should be in line with the requirements of the standard value of the specific model (generally 440 Ω), such as the resistance value is not in line with the requirements, the oxygen sensor should be replaced.
3, the oxygen sensor voltage output signal detection, is installed in the oxygen sensor wire connector, from the signal terminal lead a wire, start the engine, so that the engine reaches the normal operating temperature, and maintain the engine idling, at this time, with a voltmeter to detect the output voltage of the oxygen sensor signal terminal.
When unplugging the high-pressure wire of a cylinder (fire break), the oxygen content in the exhaust will drop, if the voltage indicated by the voltmeter voltage increases, indicating that the oxygen sensor performance is good (the oxygen sensor output voltage is generally between 0.2 ~ 0.9V, and its range of variation is about 0.5V).