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The oxygen sensor is max two years old (Bosch unit), could it be on its last legs already? The MAF was replaced a year ago with a new, rebuilt Bosch-unit.
Could something else cause this?
Have you used any silicone containing products on a intake gasket etc.? A O2 sensor should have a service life of at least 60,000 miles. But they can get fouled by silicone contaminants and stop working. The tip of the O2 sensor will be covered in white residue if this has happened.
Also you should not use any WD40 in the engine bay nearby the O2 sensor. I did not know this and have probably wrecked mine. But mine is probably wrecked anyway as I have a rear cam seal leak that drips oil on the wiring for the driver side O2 sensor....
‘Clearly the oxygen partial pressure on the exhaust sampling side of the sensor is never likely
to exceed that on the inner control surface so there would be a gradual depletion of oxygen
within the sensor if it were totally sealed. Lambda sensors have been made with vent holes in the outer body for this reason but these can be susceptible to contamination from any of the fluids or filth likely to be found in the lower reaches of an engine bay. Fortunately the amount of oxygen required is so minute that seepage between the strands of the signal wire and its insulated sleeving has been found to be sufficient for the purpose. This does mean that anything that might seal the insulation of the wires could cause the switching action to deteriorate so it is very important that crimp connections are used rather than soldered joints when renewing or repairing sensor wires. Even use of contact cleaner spray should be avoided.’
05-29-2015, 10:15 AM
AAN engine fault codes
