Theft of catalytic converter
catalytic converter are also at risk of theft,
Pipe cutters are often use to quietly remove the catalytic converter
but other tools such as a portable reciprocating saw can damage other components of the car of catalytic converter,
such as the alternator, wiring or fuel lines, with potentially dangerous consequences.
Rising metal prices in the U.S.
during the 2000s commodities boom led to a significant increase in converter theft.
A catalytic converter can cost more than $1,000 to replace, more if the vehicle is damage during the theft.
From 2019–2020, thieves in the United Kingdom were targeting older-model hybrid cars which have more precious metals than newer vehicles
—sometimes worth more than the value of the car—leading to scarcity and long delays in replacing them.
Diagnostics of catalytic converter
Various jurisdictions now require on-board diagnostics to monitor the function and condition of the emissions-control system, including the catalytic converter.
Vehicles equipped with OBD-II diagnostic systems are designe to alert the driver to a misfire condition
by means of illuminating the “check engine” light on the dashboard
, or flashing it if the current misfire conditions are severe enough to potentially damage the catalytic converter.
diagnostic systems take several forms
Temperature sensors are use for two purposes.
Modern catalytic-converter designs are not as susceptible to temperature damage and can withstand sustained temperatures of 900 °C (1,650 °F).
Temperature sensors are also use to monitor catalyst functioning:
usually two sensors will fit, with one before the catalyst and one after to monitor the temperature rise over the catalytic-converter core.
The oxygen sensor is the basis of the closed-loop control system on a spark-ignited rich-burn engine;
however, it is also use for diagnostics.
In vehicles with OBD II, a second oxygen sensor fit after the catalytic converter to monitor the O2 levels. The O2 levels are monitor to see the efficiency of the burn process. The on-board computer makes comparisons between the readings of the two sensors.
The readings are tak by voltage measurements.
If both sensors show the same output or the rear O2 is “switching”,
the computer recognizes that the catalytic converter either is not functioning or has been remove,
and will operate a malfunction indicator lamp and affect engine performance.Simple “oxygen sensor simulators” have been develope to circumvent
this problem by simulating the change across the catalytic converter with plans and pre-assembled devices available on the Internet.
Although these are not legal for on-road use, they have been use with mixed results.
Similar devices apply an offset to the sensor signals, allowing the engine to run
NOx sensors are extremely expensive and are in general use only when a compression-ignition engine fit with a selective catalytic-reduction (SCR) converter
When fitted to an SCR system, there may be one or two sensors.