Car failed inspection; told I need to "build up the drive cycle"?

[irocz0r]

Hey guys, I've got a 2015 FR-S with just under 25,000 miles. My only mechanical mod is an axleback exhaust.

I just got the car inspected and it failed for "O2 sensor not ready" and "evap system not ready".

It doesn't have a 'check engine light' and it drives great.

The guys at the inspection shop told me to try driving it for about 50 miles and come back in a couple days, and I think they did mention "drive cycles". That sounded like BS so I called the dealership and spoke with a tech advisor. He said something similar. There doesn't seem to be anything wrong with the car, so just drive it to "build the drive cycles up".

The dealer tech also asked me if I changed the battery or jump started the car recently, which would reset the car's computer. I haven't had to jump start the car in months.

Now, what the heck is a drive cycle? What exactly is going on? I haven't been driving the car for more than a couple miles at a time lately, could that have an effect on it? Should I disconnect and reconnect the battery to reset the computer, then drive it for 50 miles, like I would reset my modem? Do I need to get on the highway and drive for a period of time, or will driving 50 miles throughout short drives of a couple of miles at a time do it?

[jasonojordan]

Did you buy the car used or new?

[irocz0r]

Originally Posted by jasonojordan

Did you buy the car used or new?

Brand new

[Tcoat]

Originally Posted by irocz0r

Hey guys, I've got a 2015 FR-S with just under 25,000 miles. My only mechanical mod is an axleback exhaust.

I just got the car inspected and it failed for "O2 sensor not ready" and "evap system not ready".

It doesn't have a 'check engine light' and it drives great.

The guys at the inspection shop told me to try driving it for about 50 miles and come back in a couple days, and I think they did mention "drive cycles". That sounded like BS so I called the dealership and spoke with a tech advisor. He said something similar. There doesn't seem to be anything wrong with the car, so just drive it to "build the drive cycles up".

The dealer tech also asked me if I changed the battery or jump started the car recently, which would reset the car's computer. I haven't had to jump start the car in months.

Now, what the heck is a drive cycle? What exactly is going on? I haven't been driving the car for more than a couple miles at a time lately, could that have an effect on it? Should I disconnect and reconnect the battery to reset the computer, then drive it for 50 miles, like I would reset my modem? Do I need to get on the highway and drive for a period of time, or will driving 50 miles throughout short drives of a couple of miles at a time do it?

Drive cycle would be just that. Do some mixed high and low speed driving. Hit the highway and vary the speed and revs. I would do as many miles as you can.
DO NOT reset the ECU or you will be back to square one.
Cars that do not get driven much frequently fail emissions tests for several reasons and like your case they are frequently simple sensor items where a bit of driving will bring them back into line.


Oh almost forgot! Go back for the retest right after driving for a while. Don't let it sit for days or the sensors may go back to the issue.

[jasonojordan]

Originally Posted by Tcoat

Drive cycle would be just that. Do some mixed high and low speed driving. Hit the highway and vary the speed and revs. I would do as many miles as you can.
DO NOT reset the ECU or you will be back to square one.
Cars that do not get driven much frequently fail emissions tests for several reasons and like your case they are frequently simple sensor items where a bit of driving will bring them back into line.

This ^ I was going to ask if you replied it was gotten used if it had been tuned but since it was new good to go.

[irocz0r]

Originally Posted by Tcoat

Cars that do not get driven much frequently fail emissions tests for several reasons and like your case they are frequently simple sensor items where a bit of driving will bring them back into line.


Oh almost forgot! Go back for the retest right after driving for a while. Don't let it sit for days or the sensors may go back to the issue.

Thanks for the tips, this explains a lot. I have been using the FR-S like a weekend car and have been driving my Accord and E30 a lot more.

[Tcoat]

Originally Posted by irocz0r

Thanks for the tips, this explains a lot. I have been using the FR-S like a weekend car and have been driving my Accord and E30 a lot more.

Yep, that would do it. It always seems like a good idea to run them as little as possible but that can bring up some issues (as you have found out) even if they are really minor. Would be better for the car if you took it out at least one day of the week. When you do take it out make sure that you run it long enough that it gets fully warmed up as well. Running for a couple of miles and then shutting down can result in some weird moisture build up in intakes and exhaust. Nothing quite like a muffler that rots from the inside out (it takes years so don't panic).

[DarkSideFRS]

i usually rev the car like crazy before i go for a smog test... drive it for a good 15 mins like that and u should be good

[ls1ac]

There are readiness codes that need to be cleared. this is to keep people from clearing the a failed code and driving in the test station. There are certain drive requirements to clear the codes. Most states will pass with one readiness code not cleared.
Most of the OBD2 readers will display both types of codes.

[gravitylover]

In my state a car must have a minimum of 75 miles driven after codes have been cleared. A car that is rarely driven, like a weekend car, also needs the same minimum miles driven in a short amount of time (don't remember specifics) to ensure nothing is wrong. If these requirements aren't met the vehicle will fail.

[Tcoat]

Originally Posted by gravitylover

In my state a car must have a minimum of 75 miles driven after codes have been cleared. A car that is rarely driven, like a weekend car, also needs the same minimum miles driven in a short amount of time (don't remember specifics) to ensure nothing is wrong. If these requirements aren't met the vehicle will fail.

This makes sense!

[extrashaky]

The easiest way to understand this is to suppose you have a problem that gives you a CEL. Maybe it's a vacuum leak, or a marginal O2 sensor, a bad gas cap, an intermittent misfire, etc. If you reset the computer or clear the codes, it might take a while for the monitoring system to be sure again that the problem is still there. Maybe you could drive it 20 or 30 miles before the CEL lights up again.

Knowing you can't pass your inspection with a CEL, you might try to get clever at this point and clear all your codes before taking the car for inspection, hoping that the CEL doesn't come back before you pass. However, the car is equipped with readiness monitors that prevent you from doing that by tracking whether the car has been driven long enough for OBDII system to give an accurate picture of the condition of the vehicle. The readiness monitors tell the inspector, "This car may or may not pass inspection, but I don't know yet because this guy reset his codes, and I haven't been watching long enough since then to be sure."

When the inspection station hooks up to your OBDII port, they can see the state of the readiness monitors. Different states have different rules, but usually if you have two or three incomplete or not ready readings, you can't pass until you come back with those monitors showing ready. To get to that, they must go through enough "cycles" for there to be confidence that the OBDII system has accurate readings and still isn't throwing trouble codes. Depending on the monitor, "cycle" can mean engine start/stop cycles or just sufficient miles or run time. When they told you to go build up the cycles, they just mean to drive it long enough for the monitors to show ready.

For most people that's a guessing game, but I use Torque with a bluetooth OBDII adapter and can see my readiness monitors. That's a pretty handy thing to have if you've been told to go drive it and come back later, but you need your emissions sticker today and don't have time to waste on several days of driving to be sure.