`98 A4 51,000 mi. Dont get much mileage, about 400 this summer, with NO issues. Has been sitting for 3 Mo. with out driving. I start it about once a week or so, warm it up a little, no codes. NOW its time for (Colorado) emission test, plates due. Started it today to warm it up, CHECK ENGINE light came on ? Half tank of gas, checked gas cap..... I know there is something about reseting codes and not being able to get emissions till it cycles? Any truth to this? I know I need to check the codes. Any advice to the check engine light or any procedure I can due to get it pass emissions going forward? I have never had any issues before. Thanks for any advice.

 

To enter the Diagnostic Display function perform the following steps in order:

1. Turn ON the ignition switch, engine OFF.
2. Press the RESET button to acknowledge any warning messages present.
3. Press the OPTIONS button on the Driver Information Center (DIC) and hold.
4. While holding the OPTIONS button press the FUEL button 4 times within a 10 second period.
5. System will first enter automatic display mode followed by the manual display mode.

The automatic display feature allow you to read each module DTC display function in an automatic display sequence. Each system module DTC will be displayed for 3 seconds followed by a 1 second pause before the next DTC is displayed in an automatic sequence. If no DTC information is sent to the IPC from the system currently displayed on the IPC, the IPC will display NO CODES for that system. At any time during the automatic display function, the manual display feature can be activated by pressing any button on the DIC except the E/M 5 button. The E/M 5 button is used to completely exit the DIAGNOSTICS mode at any time. If there is a communications problem between any system, the IPC will display NO COMM when the IPC is trying to communicate with that system. When all DTCs have been displayed for all systems, the IPC will display NO MORE CODES for 2 seconds then will enter the manual display mode, waiting for manual mode operation.

The manual display feature allows you to manually select each module DTC display function. The manual mode will automatically be entered after the automatic DTC display sequence is complete, or can be entered at any time during the automatic mode by pressing any button on the DIC except the E/M 5 (E/M 5 button is used to exit the DIAGNOSTIC mode at any time). When the manual mode is selected, the IPC will display the MANUAL DIAGNOSTICS mode message for 2 seconds, or until any button on the DIC except the E/M 5 is pressed. After the MANUAL DIAGNOSTICS mode message is displayed, the IPC will display the first system abbreviation and quantity of codes stored for that system, then the IPC will wait for further instructions. The buttons on the DIC provide the following functions when operating the on-board diagnostic feature in the manual mode:

DIC Button Function
FUEL 1 Previous DTC
GAGES 2 Next DTC
TRIP 3 Previous System
OPTIONS 4 Next System
E/M 5 Exit Diagnostics
RESET Clear DTCs

 

That is exactly what you need to do. Without knowing why the CEL is one, we cannot help.

 

IF,,,you clear any DTCs, disconnect the battery, or reprogram the PCM, the emissions NOT ready flag in the PCM will prevent you from passing the emissions test. You have to complete a number of drive cycles before the emissions ready status flags are set.

There is a GM Drive Cycle procedure that you can do to accelerate the time necessary to set the emissions ready status.

If you run out of time before the test is due, go ahead and take the emissions test and get a Emissions FAILURE slip. That will give you an additional 30 days to hash things out and fix what needs to be fixed to pass the test 100%

BC

 

Yes Bill is correct--after a battery disconnect or after deleting codes the ECM goes thru a seies of " readiness tests" basically it's just checking all the emmisions related sensors---There are vehicle specific procedures to get all the readiness tests re-set to "ready" but basically you have to do 2 complete cold start drive cylces---And by cold i mean cold like an AM start----Then you need to drive it about 25 miles in each cold stat cycle in various condtions----city stop and go-- a few WOT blasts thru 2 gear and then freeway cruising at at 55--60- and 70 MPH-----Another thing that I've done is to volenteer to the smog guy that you have dis-connected the battery to do some maintenance--Quite often if they know that you dis connected the battery recently they will let you slide on the readiness tests-----