What is the "Drive Cycle" needed to reset the engine code

[ziprhead]

Hi,

I'm not sure I'm calling this the right thing which may explain me not being able to find it in the search. But, I have had my check engine light reset and I think (hope) that my problem is fixed, however I understand that there is a certain "drive cycle" that cars need to go through before they have all the information they need to verify that the emissions systems on the car is indeed running properly.

I have heard some people say a certain number of miles, etc.?

It will need to be smog checked, and I don't want to pay just to find out that the computer doesn't have enough data to give an ok. Also, for my own peace of mind I would like to know at what point the car has passed the point of throwing the code again. (although I realize that it could still be an intermittent problem and throw the code a month later anyway)

Thanks!

[SaturnManiac]

I think I've heard 50 miles...and then I've heard a certain amount of open/closed loops. But if you're just trying to reset an SES code, the local auto parts store can usually do that for you.

[ziprhead]

Thanks, yeah I had it reset and just wanted to know how long before the computer has enough data collected to either trip the light again, or give the ok signal.

50 miles sounds reasonable.. What is an open/close loop? is that a starting/ turning off the car?

Thanks for the help.

[OldNuc]

Take a 20 min drive through traffic and on a highway where you can get about 5 to 10 min of cruise time at over 45 mph. Shut it off and go somewhere for lunch. Start it back up and repeat. That should do it for sure.

[fdryer]

Originally Posted by ziprhead

50 miles sounds reasonable.. What is an open/close loop? is that a starting/ turning off the car?

Before I bought my L300 I didn't have a clue too. Open/closed loop is in reference to the BIG BROTHER mandates of emissions control. Essentially, when a car is first started and coolant temperatures are below operating levels the PCM (engine computer) runs in open loop mode where the engine is running as rich as possible to quickly warm up, emissions fall by the wayside, until warm up is complete. The PCM detects the warmed up engine and enters closed loop mode where emissions are closely monitored by the O2 sensor. The O2 sensor is useless below 600F and the main reason open loop is used at the beginning of a cold engine start otherwise a HOT O2 sensor can be used immediately but not after a simple engine shutdown. The exhaust keeps the temps above the 600F operating temperature required to keep the O2 sensor working.

[OU812]

Check out the inspection laws in your state. I'm in New York where up to 2
readiness monitors can be in not ready mode and you still pass inspection.

[Low Saturn]

There answer to your question is here:

OBD-II Driving Cycle
If you have a 96 or newer vehicle you have the OBD-II diagnostic system. This system is constantly monitoring the sensors and solenoids on the engine. If you have replaced the battery, disconnected the battery or cleared the codes after making a repair you will need to do what is called a "Driving Cycle". This will perform a diagnostic on all the systems the computer monitors. This 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 50ºC (122ºF) and within 6ºC (11ºF) 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 maximum 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.

[off-track]

Zipr, it helps if you add an approximate location and your car's vitals to your profile..

Once you've completed the driving cycle Low suggested, go back to the place that reset the code. Their scanner will also indicate which checks are complete, any that are still due and show any pending codes that may have been recorded (make sure they don't re-set it!). If all are complete, and there are no pending codes you should be good to go.

[ragde22]

Hey Low Saturn, I have a 2006 Ion (Sedan) and I have problems to activate the EVAP Monitor, All the rest of the Monitors are OK, only that one. What is the best and fastest way to activate that one!!!

Thanks.

Originally Posted by Low Saturn

There answer to your question is here:

[Madness10]

Originally Posted by ragde22

Hey Low Saturn, I have a 2006 Ion (Sedan) and I have problems to activate the EVAP Monitor, All the rest of the Monitors are OK, only that one. What is the best and fastest way to activate that one!!!

Thanks.

This is a S series forum. You need to post this in the Ion section.

[ragde22]

Sorry, I will.