As the other poster stated, the "Not Ready" status means that the component monitor for that system (EVAP) has not even attempted to "Run" (Not that it has run and failed, this will flag a code and turn on the CEL)
The reason(s) that the EVAP monitor has not run will fall into a couple of different categories:
1. The "Pre test conditions" have not been met.
2. The "Drive Cycle" has not be executed properly.
3. There is a problem with the PCM (Powertrain Control Module) that will not allow the EVAP monitor to run.
4. The Temperature or Elevation are outside of the allowed range for the monitor to "Enable"
5. The FLI (Fuel Level Indicator) is not within the
The EVAP system monitor is the hardest component monitor to get to "Run" on a vehicle!
Depending on your driving habits, It may still not have run even in 6,000 miles, the "Drive Cycle HAS to be followed to a tee or it will not run!
First, scan the PCM to see if code P1000 is stored. (I/M readiness code P1000= Monitor Testing Not Complete)
Pretest conditions:
Engine cool down event completed (ignition "off" for at least 8 hours).
MIL is off.
No Emission related DTC's are present.
BARO signal more than 22" Hg.
Engine load between 20-70%.
Engine runtime between 330-1,800 seconds. (5? to 30 minutes) After 30 minutes engine run time the EVAP monitor will NOT run!
Fuel level between 15-85% (30-85% for fuel tanks larger than 25 gallons). (the higher figure being more desirable)
Fuel tank pressure between -17.5 H2O and 1.5 H2O vacuum.
IAT signal between 40-100oF (4.4-37.8oC).
Purge flow between 0.05 lbm/min and 0.10 lbm/min
Purge duty cycle between 75% and 100%.
VSS signal between 40-75 mph.
EVAP monitor Test Drive Cycle Instructions:
Start the engine without turning off the ignition key. Allow the engine to run at idle speed for 15 seconds.
Accelerate at part-throttle to 40 mph (64 km/h) and maintain that speed until the ECT PID reaches 170oF (76.7oC). Verify that the IAT PID is within a range of 40-100oF (4.4-37.8oC) so the EVAP Monitor will initiate. If it is in range, go to step 4. If it is not, or if the altitude is more than 8,000 feet (2,438 m), the vehicle must be parked for a minimum of 8 hours to bypass the EVAP Monitor and clear the DTC P1000. Once this bypass step is completed, repeat test steps 2 through 5.
Accelerate at part-throttle to between 40-55 mph (64-89 km/h) and maintain that speed for 10 minutes while avoiding any hills or sharp turns. To initiate the EVAP Monitor, the TP MODE PID should = PT, the EVAPDC PID should be > 75%, and the FLI PID should be between 15-85%, or between 30-85% on fuel tanks with a capacity over 25 gallons.
NOTES:
One of the main causes for the EVAP monitor NOT to run is "Fuel Slosh" in the fuel tank, this will abort the EVAP monitor test!
ADDED:
Also, to your question, no, if the gas cap was bad, it would run then "Fail" and would set a P04** series code and request the CEL to come on!
In other words NONE of the EVAP system components have been tested because the monitor has NOT run!
"Not ready" is quite different from failing. The make of the car matters a lot but the model and year could be useful, too. I have found some drive cycles on the 'net for Toyota and GM vehicles.
Replace the gas cap, it's cheap!
Get a mechanic to examine the various vacuum hoses under the car and under the hood.
Is there no way to reset the computer?
I think there is and then you have to drive 200 miles to be "ready".
It won't run the EVAP monitor until it completes the O2 monitor. You can have a slow O2 sensor that's not bad enough to set a code, but too slow to allow the monitor to start.
If you had a bad gas cap that was bad enough to prevent the monitor from running, it should have set a small leak code. I think you're barking up the wrong tree with the cap.
You and your car should probably move to a free state. My son has a diesel pickup. The owner before him installed a new fuel rod and turned the pump up. My son put an 8" stack on it. He does a smog check every time he stomps on it. He can lay a 1/4 mile trail of smog when the wind isn't blowing.
My car cannot be smogged because the EVAP and Cat Monitors show "not ready". I am very aware of all the drive cycle processes and have tried them. Also, this has been well over a year and it's been tested periodically and they still won't reset. The check engine light is NOT on.
The dealer wants a ridiculous amount of money to try to run the car through the drive cycle on a conveyor belt in hopes of getting the monitors to "ready".
My question is this:
Can a bad or loose gas cap cause the "EVAP not ready" problem? If so, and I replace the gas cap, how long would it take before the EVAP monitor would be ready to test? Would it be immediate or would another drive cycle be necessary?
