Hello All,

My 2004 coupe is scheduled for a Vehicle Emissons Test.

In the letter it states that 1996 or newer vehicles will also be tested for the On-Board Diagnostic system to see if the system is functional.

They need to connect to the diagnostic link connector(DLC).

Where is this located in the car??

Thanks!!

Paul

 

under the steering wheel,behind the dash where your feet go.

 

Should he clear any code history? Silly as it sounds they flunk you automatically if your check engine light is on. I guess that's not an issue with a Corvette. The great State of IL tries to get you and your money anyway they can.

 

They do not charge for the test. It only takes 5 minutes or less once your in the bay. It's really not a big deal.

 

Normally if you clear the codes right before you go in the car will fail the OBDII tests. Part of the OBDII system is it monitors and test parts of the emission system. It takes a bit of driving and some time for all the test to be completed. When you clear the codes these tests are reset and have to be performed again. This is by design, it keeps people from clearing their codes and running in to get it checked before it turns the light back on. When the test are reset the report "Not ready" to the emission tester, most places allows 2 "Not Ready", the evaporative fuel system will almost always fail, it will fail every time after you refuel the car.

Like said above, the OBDII connector is located under the steering wheel right above your legs. Open your door and get down on your knees and look up under the dash and you will see the connector. The panels will have a hole allowing access to the connector.

 

Depends on the state ... here in Cali the testing is done by "smog stations" that are licensed by the state, but are independant businesses. Pass or Fail, you pay for the test.

 

Hmm, glad I asked! Thanks

 

Unless you see the Check Engine Light (CEL) you will normaly pass just fine. If you had a CEL and cleared it, the emisions flag for that cell will not be ready and you will not pass. The GM OBDII emissions schedule requires a certain number of engine driving cycles to be completed before the not ready flags to be cleared. There are ways to FORCE the driving cycle to finish sooner than it normaly would:

The drive cycle is the sequence of events that must happen for the various system test programs to run on your car's computer. The drive cycle involves a cold start, and a certain amount of driving time at a variety of different loads. More details on those cycles later.
When is the drive cycle important?
First, to understand why the check engine light takes a while to come on. Not only must the appropriate test monitor run, in many cases, it must run twice, detecting the failure each time. If the test runs successfully two more times, it can turn the light back off.
Second, these system monitors must be complete to pass OBDII based emissions testing (early model years often allow a couple exceptions). If you ever get sent home from an emissions test and told to come back after some driving, you can get the job done faster by understanding the drive cycles. Remember, you can use AutoTap EFI Live, HP Tuners or another scantool to check the drive cycle status.

General Motors Driving Cycle

This will cause diagnostics to be run on all sytems. Have scanner connected while testing, using freeze frame. An interesting (and very dangerous - trust me) exercise is to use AutoTap or other scanner to watch the various monitors change from "incomplete" to "complete" as you go through the various sections of the drive cycle. Hard to look at the scanner and drive at the same time.

A complete driving cycle should perform diagnostics on all systems. A complete driving cycle can be done in under fifteen minutes.
To perform an OBDII Driving cycle do the following:

1) Cold Start. In order to be classified as a cold start the engine coolant temperature must be below 50°C (122°F) and within 6°C (11°F) of the ambient air temperature at startup. Do not leave the key on prior to the cold start or the heated oxygen sensor diagnostic may not run.


2) Idle. The engine must be run for two and a half minutes with the air conditioner on and rear defroster on. The more electrical load you can apply the better. This will test the O2 heater, Passive Air, Purge "No Flow", Misfire and if closed loop is achieved, Fuel Trim.


3) Accelerate. Turn off the air conditioner and all the other loads and apply half throttle until 88km/hr (55mph) is reached. During this time the Misfire, Fuel Trim, and Purge Flow diagnostics will be performed.


4) Hold Steady Speed. Hold a steady speed of 88km/hr (55mph) for 3 minutes. During this time the O2 response, air Intrusive, EGR, Purge, Misfire, and Fuel Trim diagnostics will be performed.


5) Decelerate. Let off the accelerator pedal. Do not shift, touch the brake or clutch. It is important to let the vehicle coast along gradually slowing down to 32km/hr (20 mph). During this time the EGR, Purge and Fuel Trim diagnostics will be performed.


6) Accelerate. Accelerate at 3/4 throttle until 88-96 km/hr (55-60mph). This will perform the same diagnostics as in step 3.


7) Hold Steady Speed. Hold a steady speed of 88km/hr (55mph) for five minutes. During this time, in addition to the diagnostics performed in step 4, the catalyst monitor diagnostics will be performed. If the catalyst is marginal or the battery has been disconnected, it may take 5 complete driving cycles to determine the state of the catalyst.

8) Decelerate. This will perform the same diagnostics as in step 5. Again, don't press the clutch or brakes or shift gears.

Hope this helps

BC

 

Illinois does NOT charge-that's where the poster is.

 

Thanks Everyone!!!

I know I can coun't on you Guys to get me the info I need.

Paul