Oxygen Tech Tips

Discolored / Seared Protection Tube Sensor Diagnosis Guide All Bosch Oxygen go through a full functional test to ensure State of oxygen sensor: sensor quality and performance as part of our manufacturing process. Greenish, grainy discoloration.

Some customers have noticed a dark discoloration on Bosch sensors and Possible cause: has escaped and entered question if the part is used. Rest assured that this discoloration is the . normal and the result Note the discoloration of Measure: of one of many the sensor protection tube Replace the oxygen sensor. Check the , head, processes that we manifold and head for wear and cracks. utilize to ensure that you receive a high-quality sensor State of oxygen sensor: Blackened, with oily contamination. from Bosch! Possible cause: Excessive oil consumption.

Measure: Pre-coated Threads Check the valve guides and seals, which may be worn. Replace the Bosch Oxygen Sensors come with conductive anti-seize compound oxygen sensor. applied to the threads right out of the box for easy installation. You do not need to add any State of oxygen sensor: additional anti-seize Dark brown discoloration. as it may get on the Possible cause: sensor protection Air-fuel mixture too rich. Measure: tube and sensing Check the fuel pressure. element and may Replace the oxygen sensor. affect sensor performance. State of oxygen sensor: Reddish or white discoloration. Reference Air Possible cause: Fuel additives in the .

Oxygen Sensors require a clean reference air sample to function properly. Measure: Bosch Oxygen Sensors are the only sensors that draw their reference air from Do not use fuel additives. Replace the oxygen sensor. the connector and through the wire harness to ensure the reference air sample is clean. It is critical that the wiring harness is not damaged during installation or that no State of oxygen sensor: Broken cable. dielectric grease is Possible cause: added to the Excessive cable tension. connector as this will Measure: Replace the oxygen sensor. affect the sensor’s Route the new cable without tension. ability to draw its reference air.

State of oxygen sensor: The molded cable tubing is damaged. Product Warranty Policy Reminder Possible cause: Bosch Premium Oxygen Sensors Impact by stone chippings. Measure: Covered: 12 Months/Unlimited Miles* Replace the oxygen sensor. Applies to Non-Commercial Passenger and Light Trucks *Please see website for additional product information: www.boschautoparts.com

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