How Long Does It Take to Reset Readiness Codes
#1
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How Long Does It Take to Reset Readiness Codes
My car has Nismo cams and occassionally it throws a check engine light for a misfire at idle. My inspection ran out at the end of February. Before I could get it inspected a couple of weeks ago my check engine light came on again. It usually clears up after three or four engine cycles. However, because the car needed to be inspected I cleared codes, but the codes have not reset to ready. I had driven the car at least 100 miles since I cleared the codes, but when I tried to get inspected the codes had not reset. After that I drove it another 30 miles and then checked today with my Scan Guage and it is still reading Not Ready when I scan it. The check engine light has not come back on. Any thoughts? How many miles do I have to drive it to get the codes to reset?
#2
350Z-holic
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It's not miles, per se, it's the completion of a "drive cycle". As a rule of thumb, most people are told to drive 100 miles, two weeks, etc. BTW, the "drive cycle" is a complex series of driving tasks, i.e. - drive for 1 minute at 60 mph, slow to 30 within 5 seconds then drive 2 minutes at 30 mph, etc.
#3
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Originally Posted by DavesZ#3
It's not miles, per se, it's the completion of a "drive cycle". As a rule of thumb, most people are told to drive 100 miles, two weeks, etc. BTW, the "drive cycle" is a complex series of driving tasks, i.e. - drive for 1 minute at 60 mph, slow to 30 within 5 seconds then drive 2 minutes at 30 mph, etc.
#4
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After a 30 mile drive this morning the codes finally reset and I was able to get the car inspected. I finally ended up driving approximately 150 miles before I got ready codes.
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OBD2 readiness drive cycle is fully explained in FSM. More about number of warm up cycles and 55 mph.............a continuous drive will take forever vs following correct proceedure.
#6
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Originally Posted by Q45tech
OBD2 readiness drive cycle is fully explained in FSM. More about number of warm up cycles and 55 mph.............a continuous drive will take forever vs following correct proceedure.
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#8
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Here's a good example of what a drive cycle looks like.
http://lyberty.com/car/drive-cycle_maxima.html
It's not for a Z but a Nissan Maxima but you get the idea of what's involved.
http://lyberty.com/car/drive-cycle_maxima.html
It's not for a Z but a Nissan Maxima but you get the idea of what's involved.
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Originally Posted by Q45tech
OBD2 readiness drive cycle is fully explained in FSM. More about number of warm up cycles and 55 mph.............a continuous drive will take forever vs following correct proceedure.
Edit: Apparently the image I posted from the FSM was not related to this issue, so I removed it. Could someone post a page or section number where this applies in the FSM?
Originally Posted by DavesZ#3
Here's a good example of what a drive cycle looks like.
http://lyberty.com/car/drive-cycle_maxima.html
It's not for a Z but a Nissan Maxima but you get the idea of what's involved.
http://lyberty.com/car/drive-cycle_maxima.html
It's not for a Z but a Nissan Maxima but you get the idea of what's involved.
Last edited by __jb; 03-31-2008 at 04:28 PM.
#10
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Originally Posted by __jb
Thanks for posting this... good information... I hunted around a bit and found the info in the EC (Electronic Controls) section of the FSM.
Here's a screen print of the page that shows how to tell if the System Readiness Test (SRT) code is thrown or not. This is useful for people that do not have a scanner. I highlighted the area in red.
Good information. Florida doesn't test for this yet, but I have a feeling that it is coming.
Here's a screen print of the page that shows how to tell if the System Readiness Test (SRT) code is thrown or not. This is useful for people that do not have a scanner. I highlighted the area in red.
Good information. Florida doesn't test for this yet, but I have a feeling that it is coming.
Is that what FSM stands for?
Be glad that Florida doesn't have it. The larger population areas of NC now have emissions testing and I believe next year it goes statewide.
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Originally Posted by ZPirate
I'm assuming from your post that this page is from a service manual for the Z.
Is that what FSM stands for?
Is that what FSM stands for?
The page I quoted is actually from the 2005 G35 Coupe Service Manual. I have a G, not a Z, but I believe the ECU and DTC codes are identical between the two.
Originally Posted by ZPirate
Be glad that Florida doesn't have it. The larger population areas of NC now have emissions testing and I believe next year it goes statewide.
#12
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FSM = Factory Service Manual.
That section from the service manual is NOT the same thing that the OP was talking about. If you reset the ECU, clear the codes with a scan tool, disconnect your battery overnight, etc. - the ODBII status will report not-ready until a drive cycle is completed. That gives the system time to determine if any problems exist. Otherwise, you could clear a code then drive to the local inspection station and you'd pass with flying colors even though you still had a problem with your car. It has to come ready on its own based on the operation of the engine, emissions systems, etc.
That section from the service manual is NOT the same thing that the OP was talking about. If you reset the ECU, clear the codes with a scan tool, disconnect your battery overnight, etc. - the ODBII status will report not-ready until a drive cycle is completed. That gives the system time to determine if any problems exist. Otherwise, you could clear a code then drive to the local inspection station and you'd pass with flying colors even though you still had a problem with your car. It has to come ready on its own based on the operation of the engine, emissions systems, etc.
#13
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Originally Posted by DavesZ#3
FSM = Factory Service Manual.
That section from the service manual is NOT the same thing that the OP was talking about. If you reset the ECU, clear the codes with a scan tool, disconnect your battery overnight, etc. - the ODBII status will report not-ready until a drive cycle is completed. That gives the system time to determine if any problems exist. Otherwise, you could clear a code then drive to the local inspection station and you'd pass with flying colors even though you still had a problem with your car. It has to come ready on its own based on the operation of the engine, emissions systems, etc.
That section from the service manual is NOT the same thing that the OP was talking about. If you reset the ECU, clear the codes with a scan tool, disconnect your battery overnight, etc. - the ODBII status will report not-ready until a drive cycle is completed. That gives the system time to determine if any problems exist. Otherwise, you could clear a code then drive to the local inspection station and you'd pass with flying colors even though you still had a problem with your car. It has to come ready on its own based on the operation of the engine, emissions systems, etc.
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Originally Posted by DavesZ#3
FSM = Factory Service Manual.
That section from the service manual is NOT the same thing that the OP was talking about. If you reset the ECU, clear the codes with a scan tool, disconnect your battery overnight, etc. - the ODBII status will report not-ready until a drive cycle is completed. That gives the system time to determine if any problems exist. Otherwise, you could clear a code then drive to the local inspection station and you'd pass with flying colors even though you still had a problem with your car. It has to come ready on its own based on the operation of the engine, emissions systems, etc.
That section from the service manual is NOT the same thing that the OP was talking about. If you reset the ECU, clear the codes with a scan tool, disconnect your battery overnight, etc. - the ODBII status will report not-ready until a drive cycle is completed. That gives the system time to determine if any problems exist. Otherwise, you could clear a code then drive to the local inspection station and you'd pass with flying colors even though you still had a problem with your car. It has to come ready on its own based on the operation of the engine, emissions systems, etc.
Here is another page from the FSM. Please read the area I highlighted in red. I believe the System Readiness Test (SRT) code is exactly what the OP was talking about.
Please understand that I am not trying to argue with you. I'm trying to figure out what is going on and what is correct.
This FSM page mentions that the SRT code is used to verify ECM self diagnosis (what you are talking about) completion for State emissions inspection testing.
There is much more to this in the FSM. I'm not going to bother posting anything else about it until I'm sure I'm on the right track.
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You get a GOLD STAR! Now read on to the desription of the drive cycle necessary.
Once you know the exact miles, number of cranks, warm up time and speed.........you can optimize [minimize] the amount of time/miles necessary to show ready for test.
Once you know the exact miles, number of cranks, warm up time and speed.........you can optimize [minimize] the amount of time/miles necessary to show ready for test.
#16
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Originally Posted by Q45tech
Once you know the exact miles, number of cranks, warm up time and speed.........you can optimize [minimize] the amount of time/miles necessary to show ready for test.
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Originally Posted by Q45tech
You get a GOLD STAR! Now read on to the desription of the drive cycle necessary.
Once you know the exact miles, number of cranks, warm up time and speed.........you can optimize [minimize] the amount of time/miles necessary to show ready for test.
Once you know the exact miles, number of cranks, warm up time and speed.........you can optimize [minimize] the amount of time/miles necessary to show ready for test.
I followed up and found the drive cycle description, but it is not as simple as the Maxima drive cycle DavesZ#3 posted above. I'll break it down and post it if anyone is interested. Seems like we might not need it anymore since ZPirate already got his Z inspected.
#18
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Originally Posted by __jb
I followed up and found the drive cycle description, but it is not as simple as the Maxima drive cycle DavesZ#3 posted above. I'll break it down and post it if anyone is interested. Seems like we might not need it anymore since ZPirate already got his Z inspected.
However, all that being said I wouldn't mind knowing what the sequence is for future reference if you don't mind posting it.
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