How to check lambda probe tester?

The Modern car has a fairly sophisticated device, and the engine is not complete without the whole set of sensors. Among these may be noted the element that is responsible for the crankshaft position, throttle plate angle, the temperature of the antifreeze and spark timing. But there is another important element. This lambda probe. What is this sensor and how to check it? Consider in our today's article.

Characteristics

Lambda probe – a small mechanism that is designed to measure the amount of residual oxygen in the exhaust gases of the vehicle. Also called an oxygen sensor. It is located in the exhaust manifold. Access to the sensor is from underneath or from under the hood (depending on the type and design of the car).

Also note that these sensors in the system may be several. One is installed behind the catalyst, the second – after. Both elements are closely interrelated. In the event of a malfunction of at least one of them on the electronic control unit of the engine will receive wrong signals. The system will prepare obviously incorrect mixture with a high or conversely a low concentration of fuel.

Note

An Important condition for the operation of the sensor is a high temperature ceramic tip. He begins to analyze the concentration of oxygen ions at 300-400 degrees Celsius. Therefore, during warm-up the ECU is guided by the averaged parameters before you heat up the tip. But in recent years, the lambda probe is modified. So, often complement his heater. It operates from a network of 12 V.

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Reasons for diagnostics

Before you test the sensor of the oxygen sensor, you need to find out whether the problems associated with its malfunction. In case of breakage of this element the driver may experience the following problems:

• Failures during acceleration.
• Jerks when trying to pick up speed.
• Unstable work of the engine idling.
• Increased fuel consumption.
• Lamp “Check engine" on the instrument panel.

If there is at least one of the above faults, it is an occasion for a more detailed examination of sensor oxygen sensor tester. But ways to diagnose several. We will look at next.

Test Options

There are several methods of how to test the sensor:

• Diagnostics of the heater.
• Check the reference voltage.
• Diagnosis signal of the lambda.

The First two are the most simple. And to check the sensor signal, this would require a dial, not a digital tester.

Define circuit heating

How to test a lambda probe? For this we need a multimeter. It must be in the mode of the voltmeter. After that you should warm up the motor, so that its temperature was 80-90 degrees. Next, kill the engine, do not turn off the ignition, and do not disconnect the probe connector (the system can write it to the memory as an error). Check the voltage first at the battery. It must be at least 12 Volts. The positive wire to the heater via a suitable fuse or relay. Find it in the circuit and connect the probes of the multimeter. Also need to find the “ground”. She served with the ECU of the engine. If the conclusions there is no voltage (less than 12 Volts), most likely lost one of the contacts in the connector. Need to find open circuit and eliminate it.

You can Also find out what the resistance of the heater probe. How to check lambda probe? The tester mode is set to measure resistance and measure this indicator between the wires of the heater. The resistance shall be not less than two and not more than ten ohms. Otherwise, there is a break contact. This sensor needs to be replaced.

Define reference voltage

How to check lambda probe multimeter? For this transfer the device back in measurement mode voltage. Turn the ignition on the car. Heat sensor not necessarily. Next, measure the voltage between the negative and signal wire. An indicator that is of the order of 0.45 Volts.

A Valid run – 0,2 Volt. If this error more than normal, most likely, the sensor has poor contact with the ground, or there is a problem in the signal circuit.

Diagnostics signal probe

This is the most complex operation. For this we need a motor-tester or a voltmeter with a needle indicator. Diagnosis is as follows. Prior to checking the lambda probe, the first step is to heat the device to operating temperatures. To do this, turn on the engine and give it run at idle three to five minutes of time. Then connect to the engine block negative probe of the tester. The designated contacts of the sensor (there may be one, two or four). To the signal wire connected the positive probe of the tester. The voltage should be between 0.2 to 0.9 Volts and switched on with a frequency ofeight to ten times in ten seconds. If the voltage is 0.45 Volts and does not change, most likely the element is faulty and requires replacement.

Note: the voltage in the diagnosis should be changed in a wide range. If this figure is around 0,3-0,7 Volts, most likely the item is defective.

Also a tester you need to check the battery voltage on the chip power supply of heater (process described above). That is heater may cause a malfunction of the oxygen sensor. Not superfluous will check its grounding.

Code values

If the sensor is warmed up and working properly, the voltage level at the signal output should be between 0.2 and 1 Volt when engine speed is 2.5 thousand per minute.

With a sharp press on the gas pedal, the meter should show exactly 1 Volt voltage. With a sharp throttle valve is closed, the tester should decrease the voltage to zero.

Experts say that the most accurate in the operation for diagnosis is the oscilloscope. The cost of the device is about a half-two thousand rubles.

How to test the oxygen sensor with 4 wires?

Such devices often found on cars «Mercedes» and «Volkswagen». How to test an oxygen sensor with four wires? First you need to make measurements of the resistance at the contacts of the heater. Responsible two white wires. Between them, the nominal resistance should be about five Ohms. Then take in hands the multimeter and connect the positive probe to the signal output. Thus untwist the engine up to three thousand revs. Hold the pedal for a few minutes. How to check lambda probe Vase? Without releasing the gas pedal, measure the voltage. After this time it should be from 0.3 to 1 Volt. Please note that on the four-pin sensor is also not allowed a run in narrow ranges. If the voltage is between 0.4 to 0.5 Volts, then the element is inoperable.

How to check the lambda sensor yourself? If you have a mechanical throttle, you can just pull the cable on the intake manifold. If the vehicle is equipped with electronic gas pedal, definitely need an assistant, which will be on your team to keep and, if necessary, to let go of the accelerator.

Summing up

Now, we find out what sensor and how to test it in several ways. As you can see, the operation is simple, but requires specific instruments. As a minimum, tests should be carried out using multi - or voltmeter. But for a more detailed diagnosis will need to have an oscilloscope.