I know your pain. It took me over three months to get the drive cycle to run. I would try it late at nite when traffic was light, around midnight, before turning in. a couple of times at 4 in the morning. Just remember that all of it doesn't have to be done at the same time. I was lucky enough to be able to watch what events ran and passed with a tech2. Talking to a neighbor who is a 30 year GM tech, said the same thing as stated here, should take 20 min.

US$252.00 - GM Tech2 GM Scanner -CANdi & TIS (Works for GM/SAAB/OPEL/SUZUKI/ISUZU/Holden)

 

You are kidding me I just paid $227.00 for a acuscan 9680 not knowing about the tech two ok so you said a co rider can read the scanner as you drive telling you as you pass each part of the evap IM test.Will it also activate the sensors and valves in a gm for you as well.
Because I think you already sold me on it because I have heard of it from each and every moderator on this site and I think if it does all that and more I got to have it.Will sell my other,s to whom ever wants them.And get it for sure.I just ordered new gm shop manuals and this scanner will help as well.

 

Just read this and be aware this is a Chinese or Korean clone: May work fine for your application - but then again may not. However, I would be very interested in how this works for you. Let us know.
GM TECH 2 Diagnostic tool - A quick word before buying on Ebay | eBay

 

If you are asking me, I think that you are probably not failing the evap test - the PCM is just not running one or more of the evap tests. I think there is a big difference.

First you should never be setting any codes, pending or otherwise - and you should not be testing or resetting anything before/after/during your drive cycles. An intermittent or pending code would not turn on the SES light, but could prevent a test or function from running. It seems you are saying that no codes pending or otherwise are present, but I feel I still need to mention this.

It seems all of your tries have been since the first of the year. Is it cold where you are at? I do believe from the Cadillac info there is a minimum cold-start temperature for the evap system testing to be run (39°F-86°F). I think this makes sense because of lack of gasoline volatility at cold temps. I see no reason for other GM models to be different. They all use the same gas.

From the Cadillac info it also does not seem that you can be guaranteed to force all tests to run during a drive cycle as they state to repeat up to 6 times if required on the EVAP - there are multiple EVAP tests to run (see my post #75). Again no reason for them to be different on different models. Furthermore I worry that you might be peturbing the system with your scanner (aka sorta the Heisenberg Uncertainty Priciple - can't watch things without affecting things).

Maybe try it on the next warm day where temps can be verified with your scanner to be above 40°F before startup. Don't forget to shut key off and let sit after pulling the OBD2 plug for 5 minutes to let the O2 sensor heaters cool down before doing the cold start and don't plug in your scanner again during the drive cycle. See if that works for you.

I would continue to do the drive cycle from home as you have been for the Blazer (not the Cadillac procedure).

One more thing... the sensor temp difference requirement when starting the drive cycle is NMT 10.8°F. The 6° difference spec is in Celcius (=6°C), so make sure you are working in the correct units.

Hope this helps... based on what you have told us, it's all I got for you. You will appreciate the manuals if you are keeping this vehicle. I always buy a set of factory manuals whenever I buy a car (that I will be keeping). Warning, you may have to dig and search for the info that you want to learn. They don't always present what you want to know in a logical section. You have to get used to how the manuals are structured if you want to find certain info (especially operational descriptions).

Les

 

Info for running just the EVAP part of the drive cycle tests - 2001 Blazer Factory Manual. This is pretty much the same as the Cadillac procedure I posted (except temp spread between air temp and cooling temp but has additional info here.

--------------

I/M EVAP System Set Procedure DESCRIPTION
The purpose of this test is to satisfy the enable criteria necessary to execute I/M readiness diagnostics for the evaporative emission (EVAP) system. The test may be used to set the I/M System Status indicators to YES. Service Bay Tests are included on the scan tool for some systems depending upon vehicle make and model. The test is designed to allow the EVAP Diagnostic Tests to run in service bay conditions. Ensure the vehicle meets the requirements listed in Conditions for Running before performing either EVAP System Test. Failure to meet the necessary requirements may produce inaccurate test results.

CONDITIONS FOR RUNNING

Non-Scan Tool Service Bay Test Equipped Vehicles

• The barometric pressure is more than 75 kPa .
• The fuel level is between 1/4 and 3/4.
• The battery voltage is between 10-18 volts .
• The test will initiate only after a cold start. The control module considers the engine to be cold it the following conditions are met:
• The engine coolant temperature (ECT) is between 3.75-30°C (39-86°F) .
• The intake air temperature (IAT) is between 3.75-30°C (39-86°F) .
• The difference between the ECT and the IAT is less than 8°C (14°F) .

Scan Tool Service Bay Test Equipped Vehicles

• The barometric pressure is more than 75 kPa .
• The engine coolant temperature (ECT) is less than 80°C (176°F) .
• The fuel level is between 1/4 and 3/4.
• The battery voltage is between 10-18 volts .

DIAGNOSTIC AIDS
Extreme high or low ambient temperatures may prevent the EVAP System Tests from initiating. Performing a visual inspection prior to running the EVAP Service Bay Test may prevent having to repeat the test. A loose fuel cap may cause a Service Bay Test to abort or fail and prevent the I/M System Status from updating. A failed or aborted test will require the vehicle to cool down in order to meet the enable criteria to run another test.

The I/M System Status does not indicate whether the test has passed or failed, only that a decision was made. When all of the diagnostics for a specific system have run and passed, the I/M System Status will update to YES. If a test for a specific system has failed, the I/M System Status will update to YES, indicating a determination was made, even if all of the required tests have not run. When a failure occurs, the Emission Related DTC portion of the I/M System Status display will indicate the malfunction indicator lamp (MIL) is requested. The I/M System Status also registers the number of diagnostic trouble codes (DTCs).

The first failure of a type B DTC does not constitute a final determination of pass or fail, and will not update the I/M System Status to YES. A second trip is required, and all the conditions to run must be met in order for the test to run again. These conditions may include a partial to complete engine cool down.

The I/M System Status will update only when the DTC fails the second time, or all of the tests pass.

If there is an impending failure, the system may require more time to run the diagnostic than was allotted in the set procedure. If the test does not run after numerous attempts and no DTC is set, review the appropriate scan tool data list and the service information for an indication of why the test does not complete. Some tests may abort due to changes in the conditions while the test is running. For example, changes in engine load, such as a cooling fan or an A/C compressor clutch turning ON, may cause the test to abort.

If a diagnostic test is difficult to run, observe the I/M System Status display while maintaining the necessary enable conditions until the system status updates to YES.

TEST DESCRIPTION

Steps 1-6



Steps 7-8


The numbers below refer to the step numbers on the diagnostic table.

1. Make sure you perform the I/M System Check before performing this test. Failure to do so may result in difficulty updating the status to YES. See: Computers and Control Systems\Testing and Inspection\Monitors, Trips, Drive Cycles and Readiness Codes\Inspection/Maintenance (I/M) System Check

1. This step is to determine whether or not the EVAP System Test has passed. If the system is operating correctly, the scan tool indicates that the system has passed and the I/M System Status updates to YES. If the EVAP Service Bay Test aborts because of lost enable conditions, the test can be repeated once the enable criteria is met.
2. A failed DTC during the EVAP Service Bay Test may not appear in the DTC Information display on some vehicles. The Service Bay Test displays an indication of which test failed as a directive to the appropriate service information. Some vehicles will display the test as aborted and the first failure of type B DTC appears in the DTC Information.
3. The EVAP System Test usually begins around an engine coolant temperature of 80°C (176°F) . The vehicle should be operated moderately until this temperature is reached. The engine coolant temperature can be monitored using the scan tool.
4. This step is to identify a first failure of a type B DTC. A DTC only appears on the I/M System Status display when it becomes a MIL illuminating DTC. This occurs on the second failure of a type B DTC. A first failure of a type B DTC will not allow the I/M System Status to update to YES. Refer to Diagnostic Aids.
5. This step is to help identify any unique or unusual criteria required to run the diagnostic test in the event the universal set procedure does not. This information is located in the service information under Conditions for Running the DTC.
6. The I/M System Status only reports on whether or not a diagnostic has run, not what the outcome of the test was. If any emission related DTC sets after the tests are complete, the DTC will require diagnosis.

 

Is this a knock off or is a a built here in USA.

 

I can follow all that but what do you mean pull the OBDII plug for five minutes you mean pull the harness from the computer.Don't think I understand because I am sure you wouldn't tell me to pull the OBDII harness because if that was what you meant just pulling the battery would get all three memories and clear them.And what do you mean by the pcm not running the compleate evap test because that's what I have been thinking since after my 5th or so drive cycle I tell you Les iam not failing there and the temps are at about 54 degrees.Also this not having to perform different parts of the test if the pcm were requesting it all at the same time would the CPM remember the freeway portion of it if done rite and save it and add it to the warm up when done rite.

 

What do you think? Do you want me to Google that for you?

 

No the price is to low besides Les sent a link explaining the knock off,s some do work and some don't let me ask you this on your drive cycle quest did you use a knock off or your neighbors original since he was a certified gm tech I doubt he would own a knock off.

 

[QUOTE=10-78 edac;661473]What do you think? Do you want me to google it for you.No Les But thank you I think I know what you mean don't leave the scanner plugged in after checking the temp with it.One other thing It says to shut off every thing and that even the air pump could cause a fail and with the temps being what they are I have left the temp up and the vent on with the fan off thinking that was good enough.The htr on defrost as to get some warmth while moving every time forgetting the natural kick on function of the compressor during the winter to keep the seals moist so guess I should shut down the venting **** that will stop the compressor from kicking on and off. OK Les one other thing asked the Service manager at gm dealership about using four ways and e brake and he said that shouldn't cause it to fail because of the four ways and e brake but just as you said that I have tried so many drive cycles that it should have passed the evap IM by now unless it was due to the pcm just as you said. Or it could be to cold and leaving the air compressor on could have failed me to.But thank you for all that information on the evap it has made my understanding much better on the system and with the live data I think I will remain with the actron 9680 CP it can take a photo of the live data and with what you have given me to use the two will make everything easier.