As of 2015, 2001 and newer vehicles are only allowed one (1) incomplete monitor; and on certain model vehicles plus an EVAP monitor.
If your Mitusbishi Galant's battery was recently replaced, needed to be charged, disconnected, or if your Mitsubishi Galant recently needed smog check related repairs during which the ECU (engine control unit) was disconnected from the power source, more than likely the Emission Monitors (also known as Readiness Flags) were erased and you must drive your Mitsubishi Galant through an OBD II Drive Cycle in order to complete them (referred to as "Setting the Monitors").
Follow the Mitsubish Galant Drive Cycle below in order to complete (make READY) all the emission monitors:
Begin the Mitsubishi Emission Monitor Drive Cycle:
STEP 1. Begin from Cold Start, and ignition in OFF position for at least 1 hour. Insure your Mitsubishi Galant's fuel tank is between 1/4 and 3/4 full. Engine coolant temperature must be below 122°F and within 11°F of the ambient air temperature.
STEP 2. Idle. Run engine (do not drive) for 2 1/2 minutes with the accessories on (air conditioner and rear defroster). The ECU will run the Oxygen Sensor Heater self-test and EVAP Purge "No Flow" test.
STEP 3. Accelerate. Turn off the air conditioner and rear defroster and begin driving your Mitsubishi Montero. Apply half throttle until 55mph is reached. The ECU will now begin the EVAP Purge Flow test.
STEP 4. Hold your speed steady at 55mph for three minutes. During this time the Oxygen Sensor O2 response, Air Intrusive (AIS System), EGR Flow, Purge Valve, Misfire Detection, and Fuel Trim diagnostics will be performed.
STEP 5. During this step slowly let off the accelerator pedal. Do not brake or shift in order to slow down. It is important to let your Montero coast along gradually slowing down to 20 mph. The ECU will once again self-test the EGR System, EVAP Purge System and Long Term Fuel Trims.
STEP 6. Accelerate again at 3/4 throttle until 55-60mph is reached. This will perform the same self tests as during the first acceleration step.
STEP 7. Hold steady speed once again. This time at 55mph for five minutes. During this time the ECU will perform the catalyst monitor diagnostics.
STEP 8. Decelerate. This will perform the same diagnostics as in the first deceleration step. Remember not to press the brakes or shift gears.
This ends the Mitsubishi Galant Drive Cycle. Performing the drive cycle at least twice, or using your scan tool check to see if all the emission monitors are now complete prior to your next smog inspection.
