Cause
Thermal shock damage from exhaust condensation
A hot exhaust component cracked or destroyed by sudden cooling, most often by water. Exhaust systems produce a great deal of water vapour, which condenses in cool sections and pools; a sensor or a ceramic element that meets a slug of that water at operating temperature can crack instantly.
Oxygen sensors are the classic casualty. Their ceramic element runs at several hundred degrees, and water striking it cracks it — so the failure is sudden and complete rather than gradual, and it happens on a specific journey rather than over months. A sensor that failed abruptly on a short cold trip, or after driving through standing water, fits this, and the same event takes converter substrates.
Short journeys are the underlying cause, because an exhaust that never gets hot enough to evaporate its own condensation accumulates water in the silencer and low sections. So a vehicle used only for short trips destroys sensors repeatedly, which is a usage finding worth giving the owner. Check for water in the exhaust and for a blocked drain where one is fitted, before treating the failure as bad luck.
Typically a moderate job.
Codes this can cause (3)
Codes where this is a likely explanation first, rather than merely a possible one.
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