The lambda probe, it's the oxygen sensor, is one of the most important sensors for the engine control unit. It defines the oxygen content of the vehicle exhaust and, accordingly, provides information on the completeness of the combustion of the fuel. As with any other sensor, the lambda-probe may, over time, be inoperable. To make sure that the problem with the engine originated precisely because of the xylorod sensor, its functionality must be tested. How to check the lambda probe (oxygen sensor)?
How to check the lambda probe (oxygen sensor)?
To start the lambda probe, you need to look visually. On the tip of the lambda there should not be an attack of soot or lead; otherwise, the oxygen sensor is likely to change.
If the external lambda probe looks absolutely working, you can proceed to check it using a tester. Note that most of the modern oxygen sensor has a 4-wire system (the sensor has two wires going to the heating circuit, one wire is signal and one is "mass"), but there are also sensors with 2 or 3 wires.
The first thing you need to check is the oxygen sensor's heating circuits. This requires:
1. Ignition start. The lambda probe connector is not disconnected.
2. To puncture the tuntmeter (or the tester in the rain-voltmeter) of the wire which goes on the heater, or stick those prodders into the wiring slots. The voltage must be the same as the battery-about 12 V.
If you have not detected a "plus", you must check the integrity of the battery circuit (the "plus" on the lambda-through the safety). If there is no "minus", the chain with the ECU should be checked.
In addition, a voltmeter or a tester in voltmeter mode can be checked to see if the reference voltage in the oxygen sensor is present. To do this, you need to:
1. Ignition start.
2. Pin the voltage between the signal wire and the mass.
The normal reference voltage is about 0.45 V. If you get a result greater than or equal to 0.2 V, it means that there is a problem with the mass or the wing in the signal chain of the lambda probe.
Then, verify the operation of the lambda probe heater. To do this, you need to do the following:
1. Disable the lambda probe connector.
2. Measure the resistance between the wires leading to the heater by means of an ommeter or tester.
The normal resistance is between 2 and 10 Ohm. If there is no resistance at all, it means that the oxygen sensor must be changed.
If you have special equipment, you can also check if there is a signal from the oxygen sensor. To perform this test, you will need a oscilloscope or a voltmeter with an arrow. The procedure for determining the lambda probe signal is as follows:
1. Start the engine and warm it up to the operating temperature.
2. Attach the devices between the signal cable and the "mass".
3. Tale to 3,000.
Changes in the instrument indicators need to be carefully monitored. The oxygen sensor shall give a signal within 0.1 to 0.9 V. If the change range is smaller, then the sensor is not valid and it is time to change the sensor. In addition, it should be verified that 9 to 10 times are changed in 10 seconds. If the reading changes slowly, it means that the sensor has a problem with the response.
