I obviously should have had inspection done first. Replaced battery today on 09 LTZ 3.6L. Didn't want to wait until dead of winter and get stuck. Since I had the time, and inspection is due soon, I went to get that done. Car failed because "3 monitors are not ready". They are Evap, O2 sensor, and O2 Heater. Shop said car has to be driven 50 to 150 miles for computer to reset (since battery was disconnected) and pass inspection.
Does anyone know if these monitors reset strictly on mileage or on number of drive cycles?
Drive cycles. Cold to hot is one drive cycle. IE going to work, parked all day and driving home works out to 2 drive cycles as long as the trip is long enough and fast enough so PCM can run it's tests. O2 will cycle quick, evap. needs steady state cruise for a certain distance at a certain speed to complete. (35-40mph steady cruise ?)
It has been 9 days and 700 miles including 400 mile round trip from Long Island to Vermont since new battery installed and EVAP monitor has still not reset. (No codes present.) Ant ideas how much longer before the computer will finally reset? Any tricks to help things along? Car drives perfectly.
Inspection/Maintenance (I/M) System Set Procedure
Important: Whenever the ignition is turned ON, ignition positive voltage is supplied to the heated oxygen sensor (HO2S) heaters. After verifying the enable criteria, turn OFF the ignition for approximately 5 minutes to allow the sensors to cool before continuing with the test. Once the engine is started, do NOT turn the engine OFF for the remaining portion of the set procedure.
Ensure that the vehicle meets the conditions for a cold start listed above.
⇒ If the evaporative emission (EVAP) I/M System Status indicator displays NO, perform the EVAP Service bay test if applicable.
⇒ If the EVAP Service Bay Test is NOT available, it may take up to 6 drive cycles, with up to 17 hours between drive cycles, for the EVAP I/M System Status indicator to transition to YES.
⇒ If the O2S Heater System Status indicator displays NO, ensure that the ignition has been turned OFF for at least 10 hours.
Turn OFF all accessories; HVAC system, other electrical loads, including aftermarket/add-on equipment, etc.
Set the vehicle parking brake and ensure the vehicle is in park for automatic transmission or neutral for manual transmission.
Turn the ignition ON with the engine OFF for 1 minute.
Start and idle the engine for 2 minutes and until 65°C (149°F) is achieved.
Run the engine for 8 minutes within the following conditions:
• MAF parameter between 4-30 g/s
• Engine speed steady between 1,000-3,000 RPM
Apply and hold brake pedal, and shift to Drive for automatic, or apply clutch pedal for manual and operate the vehicle within the following conditions for 2 minutes:
• Mass air flow (MAF) signal between 15-30 g/s
• RPM steady between 1,200-1,500 RPM
Important: Do NOT touch the accelerator pedal during the idle period. A change in throttle position (TP) Sensor angle or an increase in engine speed may invalidate this portion of the test.
Release the accelerator pedal and allow the engine to idle for 2 minutes.
Caution: Refer to Road Test Caution in the Preface section.
Release the parking brake and drive vehicle at 24 km/h (15 mph) or slower for 2 minutes.
Continue to drive the vehicle for at least 5.5 miles between 45-112 km/h (28-70 mph) with the vehicle reaching at least 80 km/h (50 mph).
Safely stop the vehicle, apply the parking brake and shift to Park for automatic, or Neutral and release clutch pedal for manual.
Important: Do NOT disturb the vehicle or turn ON the ignition until told to do so. Disturbing the vehicle may invalidate this portion of the test.
Turn OFF the ignition and exit the vehicle. Do NOT disturb the vehicle for 45 minutes.
Observe the I/M System Status with a scan tool. All of the I/M System Status indicators should display YES.
⇒ If the EVAP I/M System Status indicator displays NO turn OFF the ignition for 17 hours, ensure that the vehicle meets the conditions for a cold start, and repeat steps 10-13 six more times, or until the EVAP I/M System Status indicator transitions to YES. If the indicator continues to display NO, refer to the Inspection/Maintenance (I/M) System DTC Table to identify the DTCs that did not run.
⇒ If any of the I/M System Status indicators display NO, refer to the Inspection/Maintenance (I/M) System DTC Table for the indicator which did not display YES. The I/M System DTC Table identifies the DTCs associated with each I/M System Status Indicator.
^ what he said, its not a s simple as the car warming up and cooling down. fuel level and engine load come into play. IIRC fuel level has to be between 85 and 15%, alot of variables that have to be right.
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