Ever since I did my lower intake gaskets on my 2003 Blazer L/S 4.3 liter I heard a air noise passenger side intake found noise to be coming from the evap control valve the small o ring below the valve.I fixed it now I am going on three Gm drive cycles still awaiting the evap im to stop blinking no hard code in commuter memory.In the Innova booklet it calls for three drive cycles and or 40 warm ups.Hope it clears soon its almost emission testing time.

 

One General Motors Driving Cycle, performed correctly, with no DTC's set before or during, will force ALL of the monitors to run and complete their tests. That's the purpose of the drive cycle. The "40 consecutive warm ups without a failure" will turn the light off, (if there is one), but it will not force any monitor to run. If there are incomplete monitors after the drive cycle, it was not performed correctly. EVAP is the most complicated monitor. Nearly every step in the drive cycle includes something for the EVAP system, which is why each step must be performed exactly as written. If the check engine light comes on before or during the drive cycle, it will abort until the problem is diagnosed and repaired, and the memories are cleared. The steps do not need to be performed in order, but they all must be performed. Trust me, if you mess up, even one time, it will know

 

Ok Captain thank you for the quick response.Now like you said the gm drive cycle has to be followed to a T now my question after the 2 1/2 minutes warm up I used the heater instead of the air like it requires so i will try it again by the book but my question is after the initial warm up it says turn off every thing and my headlights are auto on will that make a difference were it says to turn off everything.

 

What they're looking for in the first part of the test, is to create maximum load on the electrical system, to make sure the alternator can supply sufficient voltage/amperage for the oxygen sensor heaters, (hence the reason for the AC to be turned on). When it instructs to turn everything off, before you turn the ignition on, apply the park brake to the first "click", that will keep the headlights off for the test.

 

Ok Captain I get it now so today I set out to do a real drive cycle but one problem the temps here are 32 here and lower at night.And the air wont stay engaged so is the air conditioner the only way to do the drive cycle or can I use heater on full rear defrost all electrical for 2 1/2 minutes then click the e brake one notch for the rest of the test with everything off for the freeway part of it.?

 

That should be fine. It needs a heavy electrical load: high beam headlights, heater blower on high, rear defroster, wipers, etc.

 

Ok Captain I can do the warm up in my drive way 2 1/2 minutes everything on, shut off every thing drive to the freeway pull over to the side shut off car and head lights if e brake don,t work while running. apply e brake one notch if that works to shut off the auto light feature with engine running if it don,t can remove fuses left right headlight park lights and if you don,t touch the brake the lights wont come on.do the 3 min drive cycle coast to 20 mph accelerate to 55 for 5 minutes then coast to 20 mph and that should do it write.

 

The PCM is continuously "watching" for the driver to perform each requirement for each monitor. When the requirements in each step are met, the monitor completes. In other words, in step #4 you are instructed to go 55mph for 3 minutes; if you go 55mph for 5 minutes, the catalyst monitor, (step #7) will also complete. On the other hand, step #5 instructs not to touch the brake, if you do, the monitor will not complete. It will again start "watching" for the driver to duplicate the requirements in the step. Once the requirements are met exactly as written, the monitor completes.

 

Ok Captain now I know how to do it if I had a dyno it would be really easy.The E brake wont work for the head lights I can pull the left and right headlamp and the park fuses but for some reason that leaves the high beam indicator on at the dash don,t know if there is a way around it.But every thing else is possible so maybe the lights don,t need to be disconnected.I can hook up my Innova code reader put the car on heavy duty 3 ton jack stands start it run it for the warm up cycle shut off every thing accelerate to 55 mph hold for 3 minutes coast down to 20 mph again then accelerate back up to 55 mph hold for 5 minutes then coast down to 20 mph. and that should ready the evap monitor because like I said there isn't a hard code or a check engine light.It comes down to the head lights there has to be a way to turn them off without leaving a light on in the dash and one other question other drive cycles say use the speed control to keep the speed accurate do you think that would be ok or should i manual it.Also I don,t like the jack stand idea but it should be quite safe with heave duty jack stands and a 3 ton jack under it wont be driving off on me but it may take a little longer to coast down to 20 mph.

 

Cruise is ok to use.


No DTC's in memory.... If there are no hard faults in the EVAP system, it will not set an EVAP DTC until after the monitor runs, completes, and detects a fault.