Visual examination
Visual examination alone is not sufficient in verifying the performance of a Lambda sensor. Connection leads and sockets, as well as the sensor body are to be checked because deviations in these areas falsify the sensor signal. Damage to the sensor body indicates mechanical impact. Also the condition of the sensor protecting sleeve may give information about possible malfunctions.
| Heavy soot deposits cause the sensor to be blocked and interfere with reaction time. The fuel-air ratio can be either too rich or the sensor heater is damaged. In every case, the sensor should be exchanged. |
| Heavy white or grey deposits indicate that fuel additives are used or that the engine is burning oil. Certain components of the fuel additives and in the oil contaminate the sensor element. The cause must be removed and the sensor replaced.
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| Glossy deposits indicate that there is lead in the fuel. Lead attacks the platinum on the sensor element and in the catalytic converter. The sensor must be replaced. After the change it is absolutely necessary to make sure that only unleaded fuel is used. |
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