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Q: I/M monitors incomplete

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Scanned my car and read the I/M monitor. It said the evap system mon is inc and the oxygen sensor monitor is incomplete. what should I do about it? Please help, thanks.

My car has 148000 miles.
My car has a manual transmission.

A: Hey there. The two monitors not complete le...

Hey there. The two monitors not complete let you know that the computer is unable to complete the tests on both of these systems due to problems with the systems. The first thing to have done is to have the computer scanned for stored codes. You most likely will have codes to the O2 sensors or the engine is running rich like code P0172. The evaporative system may or may not store codes for a problem unless it is a code for an EVAP leak like P0455. This may be caused by a leaking gas cap or a purge valve that can not seal shut causing the leaking evaporative system.

This leaking purge valve will cause excessive fumes from the system to flood the engine with fumes causing the engine to run rich and cause the O2 sensor rich codes and the monitor to not complete. I recommend checking the purge control valve checked for leaks and replace it if it is leaking vacuum. The codes should be cleared and then the vehicle may need to be driven for a week before it will clean all the monitors. If you need to have this checked, a qualified pro from YourMechanic can come to your car's location to diagnose any codes and proceed with repairs.

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