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Ken, Saturn Mechanic
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Special: a OBD2 drive cycle and Saturn says the sensors..200 miles

Customer Question

Is there a special drive cycle to reset the sensors on a saturn 2001 sl2? if there is what is it? I am being told that I must preform a OBD2 drive cycle and Saturn says the sensors will reset automatically if you drive it for 200 miles?
Submitted: 8 years ago.
Category: Saturn
Expert:  Ken replied 8 years ago.
Hi and thanks for your question. I found a bulletin on the I/M Flags. Read this over and then let me know if you have any question. Ken 2001 Saturn SL2/SC2/SW2 | SL, SL1, SC1, SW1, SL2, SC2, SW2 (VIN Z) Service Manual | Engine | Engine Exhaust | Document ID:(NNN) NNN-NNNN
#00-06-04-033B: Info - I/M Readiness as Part of Emission Inspection and Maintenance Program for OBD II Vehicles - (Oct 10, 2006)

Subject:I/M Readiness as Part of Emission Inspection and Maintenance Program for OBD II Vehicles

Models:1996-2007 GM Passenger Cars and Light Duty Trucks (Including Saturn)
2003-2007 HUMMER H2
2006-2007 HUMMER H3
2005-2007 Saab 9-7X
with OBD II Emissions Systems


Attention: "GM of Canada" and "IPC" Dealers are not authorized to utilize this Service Bulletin.


This bulletin is being revised to add models, model years and additional information on emission testing. Please discard Corporate Bulletin Number 00-06-04-033A (Section 06 - Engine-Engine Controls).

Inspection Maintenance (I/M) Program

Several states require that vehicles pass OBD system l/M emissions inspection. These inspections may apply to any 1996 and newer model year OBD II equipped passenger cars and light duty trucks.

As part of an OBD I/M emission inspection, the vehicle's I/M readiness status is checked to ensure that the vehicle's OBD system has properly evaluated the emissions systems of the vehicle for proper operation. To ensure vehicles are capable of passing this portion of the inspection, technicians can review the l/M readiness test status using the l/M System Status display on the Tech®2. This display provides test data that will verify whether the vehicle's OBD systems have run. States performing inspections on an advisory basis will not reject vehicles for not being I/M-ready.

Conditions for Updating the I/M System Status

Each OBD II system requires at least one diagnostic test. A system monitor is complete when all of the DTCs that report to the system monitor have run and passed or failed. The results of a failed test are reported by a diagnostic trouble code (DTC).

Once all of the tests are complete, the l/M System Status display indicates YES in the "Completed" column. For example, when the HO2S Heater Test indicates YES, all oxygen sensor heaters have been diagnosed.

When any required test for a specified system has not run, the "Completed" column under l/M System Status displays NO. The following is a list of conditions that would set the l/M System Status indicator to NO:

The vehicle is new from the factory and has not yet been driven through the necessary drive conditions to complete the tests.
The battery has been disconnected or discharged below operating voltage.
The control module power or ground has been interrupted.
The control module has been reprogrammed.
The control module DTCs have been cleared as part of a service procedure.

Monitored Emission Control Systems

The OBD II System monitors all emission control systems that are on-board. Not all vehicles have a full complement of emission control systems. For example, a vehicle may not be equipped with AIR or EGR.

The following is a complete list of the vehicle's systems that may require monitoring by the OBD system:

Air conditioning system
Catalytic converter efficiency
Comprehensive component monitoring (emission-related inputs and outputs)
Evaporative Emissions (EVAP) system
Exhaust Gas Recirculation (EGR) system
Fuel delivery system
Heated catalyst monitoring
Misfire monitoring
Oxygen sensor system (O2S or HO2S)
Oxygen sensor heater system (HO2S heater)
Secondary Air Injection (AIR) system

If a specific vehicle is not required to monitor one or more of the above listed systems, the Tech®2 display will read "not supported." Any non-supported system will not be considered when determining the readiness of the overall system.

For the specific DTCs related to each system, refer to SI (Service Information) for further diagnostic information on conditions for running the DTC or refer to the publication information mentioned in this bulletin to order the Inspection Maintenance Emissions Diagnostics Manual and follow the I/M Readiness Testing System DTC Tables. Systems such as fuel delivery, misfire, and comprehensive components may not be listed in a system status list. These tests run continuously on some vehicles and may not require an indicator.

Diagnostic Aids

The l/M System Status display indicates when the control module has completed the required tests. This does not necessarily mean that the test has passed, only that a decision was made. If the diagnostic fails, a DTC will indicate the failure. If a failure indication is present, it may prevent other required tests from running. For example, a DTC for the control circuit of the relay controlling an AIR pump may not be listed in the Inspection Maintenance System DTC Table because it is a continuous test. If this DTC is set, the Active Tests for the AIR system may not run and AIR system readiness could display "NO."

The l/M System Status information may be useful for a technician to determine if diagnostics have run when verifying repairs.

Expert:  Ken replied 8 years ago.
It may take 3 or 4 Cold starts to completely test all of the I/M test. For a cold start you may need to let the car sit over night before it will test more systems. Ken
Customer: replied 8 years ago.
I have failed the emissions test The Coolant temp sensor was not matching the anbient temp sensor when cold. The difference in temp was keeping the monitors from resetting. The coolant temp sensor was replaced and now I am being told that I must preform a OBD2 drive cycle. How do I do that. according to the instructions it sounds impossible. I called Saturn and they claim just normal driving will reset the monitors but they didn't seem to be to positive about it. I need to know the answer normal driving or OBD2 drive cycle.
Expert:  Ken replied 8 years ago.

The purpose of the Inspection/Maintenance (I/M) Complete System Set Procedure is to satisfy the enable criteria necessary to execute all of the I/M readiness diagnostics, and complete the trips for those particular diagnostics. When all diagnostic tests are completed, the I/M System Status indicators are set to YES. Perform this test when more than one of the I/M System Status indicators are set to NO.

Conditions for Running

Cold Start

The barometric pressure (BARO) is more than 74 kPa.
The start-up engine coolant temperature (ECT) is between 4-30°C (39-86°F).
The start-up intake air temperature (IAT) is between 4-30°C (39-86°F).
The difference between the startup IAT and the startup ECT is 8°C (14.4°F) or less.
The battery voltage is between 9-18 volts.
The fuel level is between 15-85 percent.
The Evaporative Emission (EVAP) System requires the above conditions along with the following:
- Three or more drive cycles with a minimum of 17 hours between cycles
- The estimated ambient temperature at the end of this drive cycle is between 2-32°C (36-89°F).
- The shutdown ECT is 70°C (158°F) or higher.
- A refueling event is not detected.
Expert:  Ken replied 8 years ago.
Are you in California? Ken
Customer: replied 8 years ago.
I assume from your answer that I start the car cold and drive it at any speed for several miles, like 50 or so then wait 17 hours and do another cold start and do this for 3 times and all monitors will reset. I do not need to run the air conditioning or the rear window defogger and maintain a constant speed of 55 mph then decelerate to 20 miles per hour for certain periods of time or for a certain mileage?
Expert:  Ken replied 8 years ago.

That is right, First time get on the freeway and go 10 miles at a steady speed, then turn around and come back 10 miles. This should learn the O2 Sensors. Then let it sit over night. Drive again on the freeway 10 miles, same as the first trip. On the 3rd, start and drive in town and on a road that you can do 25 to 40. stop and go is ok. Try to go 4 mins at a steady speed some time in this trip. If you are in California, you do not need to reset all of the flags to get a shog test. Only a majority, 3 out of 5. or 3 out of 4. The evap test can take along time to run and pass.Your local shop can look at the I/M flags to see how may have run and passed.

I am glad you replyed back, Ken
Customer: replied 8 years ago.
In Illinois all must reset. is this answer still good for Illinois?
Expert:  Ken replied 8 years ago.
I am sorry I never answered your first question. There is not a drive cycle that you can do to reset all the I/M flags at one time. They did this so you can't clear trouble codes and then go get a smog check done. It forces people to drive them a few days before they can test. Ken
Ken and 8 other Saturn Specialists are ready to help you
Expert:  Ken replied 8 years ago.
It the same answer and drive pattern to get the flags to reset the fastest. Ken
Expert:  Ken replied 8 years ago.
Have a shop check your I/M flags in 3 or 4 days before you test. Just ask them if they will check them with a scan tool for you. Any shop ,not just the dealer should be able to do this for you. Ken