Oxygen sensors are subject to wear: regular inspection pays off
Oxygen sensors are subject to extreme loads in the exhaust system. The functional reliability of these sensitive exhaust gas sensors should therefore be checked every 30,000 kilometers.
(Ludwigsburg, October 31, 2006) There are many reasons for excessive fuel consumption. Faulty oxygen sensors, for example: a vehicle’s fuel consumption increases by around 15 percent and statutory exhaust gas limits are no longer met. The consequences for the environment are considerable. Drivers complain of black smoke, jerky acceleration and a general lack of engine response.
Oxygen sensors are subject to extreme loads in the exhaust system – not least because of gas exchanges and temperature peaks. Wear is the inevitable consequence. On vehicles with onboard diagnostics (OBD), the sensitive sensors are positioned before and after the catalytic converter, where they continually measure the residual oxygen content in the exhaust gas. They pass on their data to the control unit, which adjusts the mixture to make it richer or leaner.
Overheating due to combustion faults, inaccurate ignition point or valve timing errors is one of the most common causes of defects. Oxygen sensors also age prematurely as a result of too frequent short journeys. Poor contacts due to oxidized connectors or contamination of the sensor element by oil residues and fuel additives can also lead to defects.
Failure to take immediate action can cause the catalytic converter to be damaged. That is why as a general rule BERU experts recommend testing the functional reliability of these waste gas sensors – which are critical to the entire vehicle system – every 30,000 kilometers and replacing them immediately if they are worn or defective. Oxygen sensors should be replaced routinely after 50,000 kilometers in the case of unheated types and after 100,000 kilometers in the case of heated types.
BERU range: oxygen sensors for around 3,000 vehicle models
BERU’s oxygen sensor range covers virtually all vehicle models on the road across Europe that are affected by wear. BERU oxygen sensors in OEM quality are currently available for around 3,000 vehicle models. What’s more, BERU oxygen sensors are simple, quick and safe to install, since they are fitted with vehicle-specific original connectors. This avoids the need for adapters and time-consuming additional installation work.
Using so-called universal oxygen sensors involves much more time and effort in the workshop. Up to five shrink-down plastic tubes have to be fitted one at a time to insulate the contact points. There is a risk of cable mix-up, inadequate electrical insulation, fatigue failure at the connectors and misinterpretation of the lambda signal due to cold soldered joints or transfer resistance. In addition, oxidation of the old connectors can corrupt the signal from the sensor to the control unit. BERU oxygen sensors, on the other hand, correspond to the original. They are tested by the TÜV in stringent test procedures and have been granted a general operating license by the German Department of Transportation.
BERU tips: how to fit oxygen sensors correctly
When fitting BERU oxygen sensors, workshop professionals must use special tools and be sure to set the correct torque. Too high a torque can destroy the special ceramic body of the sensor. The key techniques for the proper inspection and detection of faults on oxygen sensors are illustrated in an A2 poster available from BERU.
Further information for workshops and parts dealers can be found in Technical Information no. 03 “All you need to know about oxygen sensors”. This 16-page BERU brochure is packed with photos and drawings illustrating the structure, function and testing of exhaust gas sensors and identifying typical defects. The TecDoc-based BERU product CD includes up-to-date usage lists. All BERU publications are available free of charge in printed format or on CD. You can request them by e-mail to produktpresse@beru.de or order them from your parts dealer. And for rapid online searching, try the BERU product finder at http://www.beru.com/english/produkte/produktfinder.php
