
The overall smog inspection consists of three parts…the emissions test, which measures the smog coming out of the tailpipe the visual inspection, to look for broken or modified parts and the functional tests, where other systems are checked to see if they are working properly. My car passed the emissions test…who cares if the monitors are incomplete? OBD II helps ensure that the vehicle is in proper condition to run clean. If a problem turned on the check-engine light, a simple battery-disconnect could turn it off long enough to pass a smog test, even though the problem was still there. In earlier systems (OBD I) there was no long-term record stored of the state of the car’s systems. Also, if battery has been disconnected, replaced or needed a jump-start, the monitors may be erased. I f your car has recently been repaired for a problem that set a DTC (check engine on) and the technician cleared the DTC, he also erased the monitors. There are several reasons why the monitors may be incomplete. If they are not, the vehicle fails the test, because there may be problems in the system that can’t be reported by the computer. When your car gets a smog test, one portion of the test involves connecting the smog test machine to the car’s computer and checking if there are any DTC’s, and also checking to see if the monitors are ready. The status of these tests (complete or incomplete) is referred as the “readiness monitors”. (The light may say “CHECK ENGINE”, “SERVICE ENGINE SOON” or merely be an icon that looks like an engine.) What are “Monitors”?Įven if there are no problems with your car, the results of tests that have been run are stored in the computer as having been completed.
#EVAPORATIVE SYSTEM MONITOR INCOMPLETE CODE#
If a problem is detected, a Diagnostic Trouble Code (DTC) is set, and the computer turns on the “Check Engine” light. While you are driving your vehicle, its computer is constantly monitoring and running tests on the various sensors, actuators and electrical parts that make the car run properly.
#EVAPORATIVE SYSTEM MONITOR INCOMPLETE DRIVER#
The primary reason OBD II was invented is to reduce smog emissions caused by malfunctions, but it is also valuable as an alert to the driver that something is wrong…something that can affect gas mileage and drivability, or actually cause further damage to the vehicle.

OBD II is a system that has been installed in most 1996 and later cars and light trucks, intended to inform the driver of problems in the components that control the engine and transmission.

OBD II, “CHECK-ENGINE” LIGHTS, and READINESS MONITORS.WHAT ARE THEY?
