Drive Cycle?
Thread Starter
Race Director
Joined: Mar 2005
Posts: 10,399
Likes: 25
From: Austin Texas
Drive Cycle?
I just replaced the battery in my '08 C6. My State Inspection is due this month and I know from previous threads that when the battery has been disconnected the the computer requires a specific number of "drive cycles" before it will show as clear.
What exactly is a Drive Cycle and how many do I need or how long do I have to wait to pass Inspection in Texas?
What exactly is a Drive Cycle and how many do I need or how long do I have to wait to pass Inspection in Texas?
Team Owner
Joined: Sep 2005
Posts: 20,352
Likes: 568
From: Ventura County, Calif
Don't have an actual answer, sorry.
A drive cycle is one ignition on/start/drive/ignition off sequence. I've read 10 cycles to clear and also read 25 cycles to clear. Hopefully someone will have the real answer.
A drive cycle is one ignition on/start/drive/ignition off sequence. I've read 10 cycles to clear and also read 25 cycles to clear. Hopefully someone will have the real answer.
Melting Slicks
Joined: Dec 2006
Posts: 2,694
Likes: 106
Nobody knows, but yes, disconnecting the stupid battery erases the emissions 'readiness codes'. I also learned that the hard way with another car. I was told 50 miles, but that didn't do it for me. I had to put almost 100. I think it has more to do with 'ignition cycles' than miles, to be honest. But you should at least put enough miles on each ignition cycle to allow full operating temperatures, and then allow engine to cool down. By the way, as long as 2 out of the 3 codes are set, the car passes. Mine still had the 3rd not ready the last time I took the car, so glad it passed because I didn't want to put any more wasted miles on that car.
Last edited by JCtx; Mar 27, 2012 at 01:37 AM.
Race Director
Joined: Sep 2007
Posts: 16,557
Likes: 2,102
From: Peoria/Phoenix AZ
C6 of Year Finalist (performance mods) 2019
I remember reading that in the manual a couple of months ago in relation to some other problem. Something makes me think it's 3 ignition cycles but there is a time sequence involved. I'm pretty sure if you drive a couple miles and shut it down for a bit that would be a cycle. It's not that much, but that'd be a safe number.
Damn, it sucks to get old and forget stuff.
Damn, it sucks to get old and forget stuff.
Sr.Random input generator
Joined: Jan 2008
Posts: 7,719
Likes: 2,164
From: Sammamish, WA
It's not "unknown". There are actually steps to quickly finish the cycle in about 20-30 minutes. You let the car warm up idling, then go on the highway, stay at constant speed for it to do the evaporation testing, etc.; I forgot the steps, but I'm sure you can find it if you search on here or on Google.
Drifting
Joined: Nov 2011
Posts: 1,843
Likes: 330
From: western NY
http://www.obdii.com/drivecycle.html
http://www.lyberty.com/car/drive-cycle.html
I'm not at the shop right now to get the specific info for your car, but this is close. Usually the EVAP readiness monitor takes the longest to set, however, at least in NY, they allow at least one monitor to be open without failing the emissions portion of the inspection. EVAP won't run if the fuel level is below 1/4 or above 3/4 fuel level. This is handy to know if you have an older car with an EVAP problem & keeps setting the CEL. Keep the tank full, clear the codes, do a drive cycle, all monitors set except EVAP, get car inspected. Naturally it is advisable to get it repaired otherwise the CEL is always ON, and if another problem developed, you would never know it was there unless the car started to run poorly.
Sometimes it takes a bit for the cat monitor to set as well. I usually pull over to a parking lot after the last 55 mph part of the drive cycle & let it sit at idle for a few minutes, in gear (if automatic trans).
For the most part, the drive cycle is usually pretty painless. The trick is to get it up on the highway at the steady state speed like it says & all will be good. Strictly city driving will not usually work out too well.
Joe T
http://www.lyberty.com/car/drive-cycle.html
I'm not at the shop right now to get the specific info for your car, but this is close. Usually the EVAP readiness monitor takes the longest to set, however, at least in NY, they allow at least one monitor to be open without failing the emissions portion of the inspection. EVAP won't run if the fuel level is below 1/4 or above 3/4 fuel level. This is handy to know if you have an older car with an EVAP problem & keeps setting the CEL. Keep the tank full, clear the codes, do a drive cycle, all monitors set except EVAP, get car inspected. Naturally it is advisable to get it repaired otherwise the CEL is always ON, and if another problem developed, you would never know it was there unless the car started to run poorly.
Sometimes it takes a bit for the cat monitor to set as well. I usually pull over to a parking lot after the last 55 mph part of the drive cycle & let it sit at idle for a few minutes, in gear (if automatic trans).
For the most part, the drive cycle is usually pretty painless. The trick is to get it up on the highway at the steady state speed like it says & all will be good. Strictly city driving will not usually work out too well.
Joe T
Thread Starter
Race Director
Joined: Mar 2005
Posts: 10,399
Likes: 25
From: Austin Texas
http://www.obdii.com/drivecycle.html
http://www.lyberty.com/car/drive-cycle.html
I'm not at the shop right now to get the specific info for your car, but this is close. Usually the EVAP readiness monitor takes the longest to set, however, at least in NY, they allow at least one monitor to be open without failing the emissions portion of the inspection. EVAP won't run if the fuel level is below 1/4 or above 3/4 fuel level. This is handy to know if you have an older car with an EVAP problem & keeps setting the CEL. Keep the tank full, clear the codes, do a drive cycle, all monitors set except EVAP, get car inspected. Naturally it is advisable to get it repaired otherwise the CEL is always ON, and if another problem developed, you would never know it was there unless the car started to run poorly.
Sometimes it takes a bit for the cat monitor to set as well. I usually pull over to a parking lot after the last 55 mph part of the drive cycle & let it sit at idle for a few minutes, in gear (if automatic trans).
For the most part, the drive cycle is usually pretty painless. The trick is to get it up on the highway at the steady state speed like it says & all will be good. Strictly city driving will not usually work out too well.
Joe T
http://www.lyberty.com/car/drive-cycle.html
I'm not at the shop right now to get the specific info for your car, but this is close. Usually the EVAP readiness monitor takes the longest to set, however, at least in NY, they allow at least one monitor to be open without failing the emissions portion of the inspection. EVAP won't run if the fuel level is below 1/4 or above 3/4 fuel level. This is handy to know if you have an older car with an EVAP problem & keeps setting the CEL. Keep the tank full, clear the codes, do a drive cycle, all monitors set except EVAP, get car inspected. Naturally it is advisable to get it repaired otherwise the CEL is always ON, and if another problem developed, you would never know it was there unless the car started to run poorly.
Sometimes it takes a bit for the cat monitor to set as well. I usually pull over to a parking lot after the last 55 mph part of the drive cycle & let it sit at idle for a few minutes, in gear (if automatic trans).
For the most part, the drive cycle is usually pretty painless. The trick is to get it up on the highway at the steady state speed like it says & all will be good. Strictly city driving will not usually work out too well.
Joe T
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Melting Slicks
Joined: Jan 2009
Posts: 2,466
Likes: 104
From: Texas
http://www.obdii.com/drivecycle.html
http://www.lyberty.com/car/drive-cycle.html
I'm not at the shop right now to get the specific info for your car, but this is close. Usually the EVAP readiness monitor takes the longest to set, however, at least in NY, they allow at least one monitor to be open without failing the emissions portion of the inspection. EVAP won't run if the fuel level is below 1/4 or above 3/4 fuel level. This is handy to know if you have an older car with an EVAP problem & keeps setting the CEL. Keep the tank full, clear the codes, do a drive cycle, all monitors set except EVAP, get car inspected. Naturally it is advisable to get it repaired otherwise the CEL is always ON, and if another problem developed, you would never know it was there unless the car started to run poorly.
Sometimes it takes a bit for the cat monitor to set as well. I usually pull over to a parking lot after the last 55 mph part of the drive cycle & let it sit at idle for a few minutes, in gear (if automatic trans).
For the most part, the drive cycle is usually pretty painless. The trick is to get it up on the highway at the steady state speed like it says & all will be good. Strictly city driving will not usually work out too well.
Joe T
http://www.lyberty.com/car/drive-cycle.html
I'm not at the shop right now to get the specific info for your car, but this is close. Usually the EVAP readiness monitor takes the longest to set, however, at least in NY, they allow at least one monitor to be open without failing the emissions portion of the inspection. EVAP won't run if the fuel level is below 1/4 or above 3/4 fuel level. This is handy to know if you have an older car with an EVAP problem & keeps setting the CEL. Keep the tank full, clear the codes, do a drive cycle, all monitors set except EVAP, get car inspected. Naturally it is advisable to get it repaired otherwise the CEL is always ON, and if another problem developed, you would never know it was there unless the car started to run poorly.
Sometimes it takes a bit for the cat monitor to set as well. I usually pull over to a parking lot after the last 55 mph part of the drive cycle & let it sit at idle for a few minutes, in gear (if automatic trans).
For the most part, the drive cycle is usually pretty painless. The trick is to get it up on the highway at the steady state speed like it says & all will be good. Strictly city driving will not usually work out too well.
Joe T
Sr.Random input generator
Joined: Jan 2008
Posts: 7,719
Likes: 2,164
From: Sammamish, WA
Here is my question...in a drive cycle it usually starts off with the need for one to start the engine with a cold engine and idle for approximately 2 to 3 minutes...then immediately go to 40-55 MPH and keep it steady for 3 to 5 minutes. Then typically 3 to 4 other things...etcetc. My question is do they have to occur one immediately after the other? because I dont live by the freeway which means driving the car to the freeway...waiting for it to cool down then starting car letting it idle and hoping that some idiot does not interfer with reaching 55 mph at a steady pace? HELP!!! Same problem Cat not ready cant pass stupid emissions...
I'm sure you can complete the cycle regardless of where you drive. The guidelines are meant to help you complete the cycle as soon as possible.
Melting Slicks
Joined: Jan 2009
Posts: 2,466
Likes: 104
From: Texas
I dont think its thats simple unless you want to drive hundreds of miles to activate the catalyst which is the main one that does not kick in. However, in theory if you do the drive cycle perfectly it should kick in. However, many drivers are finding that even the drive cycle does not work and it may be due to them not following it to the T like I mentioned...unsure but tommorow I am hooking up my Actron OBD Scanner (it shows I/M monitors-just bought today) and doing the cycle perfectly one exactly after the other .... I will report back to see if the cat kicks in. I have already over 100 miles and still has not activated.
Last edited by Cor430vette; Mar 31, 2012 at 12:03 AM.
Instructor
Joined: May 2008
Posts: 224
Likes: 22
From: Houston TX
I finally got mine to pass inspection today. It took a period of two days from the time I reconnected the battery. At first I thought it was a matter of just putting on miles on the car but I've learned the emphasis is really the number of drive cycles and how close you can follow the suggested method to get the sensors ready for test.
I was able to get it done after 8 drive cycles but remember, numbers may vary per individual. I only needed three of four sensors ready for test (Texas). By the end of the first day the catalyst sensor was ready. Morning of day two, the O2 sensor was
. After a trip to the grocery store the O2 Heat sensor gave me the , leaving the Evaporator sensor in not ready status.
I'm fortunate enough to still be near what would be considered country backroads with plenty of straights. Just glad to get it out of the way so I can enjoy a few beers.
I was able to get it done after 8 drive cycles but remember, numbers may vary per individual. I only needed three of four sensors ready for test (Texas). By the end of the first day the catalyst sensor was ready. Morning of day two, the O2 sensor was
. After a trip to the grocery store the O2 Heat sensor gave me the , leaving the Evaporator sensor in not ready status.I'm fortunate enough to still be near what would be considered country backroads with plenty of straights. Just glad to get it out of the way so I can enjoy a few beers.
Racer
Joined: Aug 2007
Posts: 452
Likes: 2
From: Middleton Ma.
The hole thing can be done in 15mins. disconnect the battery, with a cold engine, start the engine ,turn on everything in the car, the more power drain the better. AC rear window defogger ect. Let her idle for about 3-5 mins. Get in turn off everything. Drive 50 -60 MPH for 5 miles or so. take your foot off the gas and don't touch nothing. Let her coast to almost a stop. Go get inspected. I had a 01Z06 that would not pass because some of the O2 sensors were not turning on. Took her to Chevy and they wanted to replace all of them. Search 15 min. OBD 2 test on the forum. Saved me BIG $$$$.
