P0405 egr sensor A circuit low

SOURCE: Failed the emission test

check tcc fuse in the underhood fuse box

SOURCE: egr valve on a 99 saturn sl

Take it off and look at it internally, See if you can move the diaphragm if not then it needs replacement. But you should just go ahead and replace it anyways since it is a 99 it would just be worth it

SOURCE: 2000 Saturn SL2 fails smog due to failure of OBD Self test

Some vehicles require very specific drive cycles (called "drive traces" if you perform them on a road simulator or dyno) to activate certain self-checks like the catalyst and EVAP monitors. As a general rule, doing some stop-and-go driving around town at speeds up to about 30 mph followed by five to seven minutes of steady 55 mph highway speed driving will usually set most or all of the monitors. Consequently, if you're checking an OBD II system and discover that one or more of the monitors have not run, it may be necessary to test drive the vehicle to set the remaining monitors.

You should talk to a good emission tec, if this is not throwing a code, it is hard to say if that one of the components could be bad. O2,pump,convert, HeO2, every part of the emission system.

With a 1000 miles, and doing what is says above just before the test, and ending driving at the test
should be plenty. If it is not, you will have to have each emission part checked, or when the computer
is plugged in it might show a code that did not trip dash light.

SOURCE: EGR Valve, O2 Sensor

Absolutely a bad o2 sensor can cause problems with performance. If you replace one it is highly recommended to replace both or all four depending on your vehicle. If one o2 sensor is making your vehicle run rich you will burn more fuel and in return increase the amount of carbon or unburnt fuel if you will in your egr valve you could probably get away with cleaning it but I would recommend replacing it, it will save you from having to pull it off again. Check your catyletic converter because long exposure to carbon will mess it up.

SOURCE: Service Engine light staying on

A code P0442 most likely means one or more of the following has happened: a loose or improperly affixed gas cap; a non-conforming gas cap (i.e. not factory/original brand); a small leak/hole in a fuel vapor hose/tube; other small leak in EVAP system; faulty vent o-ring seal

The EGR Valve is located on top of the intake manifold. If you are standing in front of the car it would be on your right hand side. It is cylinder in shape and has wire harness that connects to the back of the engine!

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