[Lara]

One of my Caymans (2009 Cayman S), which is predominantly a track car, was throwing a check engine code at the beginning of June. When we were at tech on 6/12, a mechanic hooked it up, discovered it was nothing, and cleared the code. We drove it for 3 days at Pitt Race the last weekend in June. Since then, it hasn't been driven and there are no codes.

I took it to the MD VEIP (emissions inspection place) yesterday. (12 min drive, if it matters.) They said their system wasn't connecting to the car (OBD, but they didn't say that) and to "drive it for a week" and come back in 8 days. What on earth? I asked how much/how long/why/what is going on. After pressing and pressing, she said -- drive it for 10 min a day in stop and go traffic. (Not ideal because it has JRZ shocks and track R comps on it, but. . .)

Can anyone shed any light on this issue? What would cause it? Ideas on how to resolve it? Thanks!!!

[cmartin]

dont overthink it. The emissions test is very simple. Connect obd2 dongle and it checks for codes and that a drive cycle is complete. Basically confirms the car is working correctly and you didnt just reset a code trying to fool them. 'Just drive it' usually works, I've never had one come back after doing so.

I found this as a pretty good description of a drive cycle

Pre-Conditioning Requirements:

Ensure the Check Engine Light is not on.

Gas tank fuel level must be between 15% and 85% during the drive cycle.

Engine temperature requirement is between 68 and 86 degrees F prior to drive cycle start.

START HERE - The Drive Trace:

NOTE: While performing the drive cycle do not exceed 3,000 rpm or 60 mph during any time.

A. Start your Porsche Cayman and let it idle for approximately 2 1/2 minutes. This will allow the ECU to diagnose oxygen sensor aging; meaning the computer will be monitoring the oxygen sensor warm-up period and reaction to rising exhaust temperatures. During this period the ECU is also testing the Secondary Air Injection system.

B. Begin driving. Accelerate to 20-30 MPH and maintain your speed for 3 1/2 minutes. The ECU will be testing catalytic converter efficiency.

C. Next, accelerate to 40-60 MPH. Once again maintain steady speed, this time for approximately 15 minutes. The EVAP system is now being tested along with adaptation range (2) and the oxygen sensor (switching).

D. Decelerate and come to a complete stop. If equipped with a manual transmission, idle in neutral for 3 minutes. If equipped with an Doppelkupplung (PDK) automatic transmission, idle in drive (D) for 3 minutes. Adaptation range (2) is now being tested.

E. Repeat steps B through D. Drive cycle complete.

Should the catalyst monitor and/or the oxygen sensor monitor not complete after completing the drive cycle twice, we recommend having your vehicle inspected by either a Porsche dealer or test and repair certified smog check center. Each of your vehicle's emission monitors have strict input parameters which must be met before the emission monitor test is initiated. For example, if your vehicle's engine never achieves closed-loop, the catalyst monitor will not run. Or, should the ECT (engine coolant temperature) sensor indicate an irregular engine temperature, the air injection monitor may not initiate. Keep in mind that neither of these two conditions may trigger the check engine light on, but they will stop the drive cycle from getting the required monitors ready. Having a repair shop attempt to complete the drive cycle utilizing a dynamometer (eliminating the need for street/highway driving) will allow them to view in real-time all sensor inputs while the drive cycle is in progress. This way they can pinpoint what may be causing your Porsche's emission monitors to not set or the drive cycle not engage.

oops. forgot to reference the src, https://www.smogtips.com/smog-questi...an-Drive-Cycle

[HoodPin]

I have similar issues with our 07 Cayman S. Emissions Testing requires the computer to be "Ready" before it will test/collect data. If the check engine light has been reset, it prevents being Ready until certain data from driving is collected.

There is apparently a "drive cycle" that can put the car in Ready status with minimal driving. Here's one of many online links that describe the procedure: https://www.smogtips.com/smog-questi...an-Drive-Cycle

Unfortunately, the Durametric reader for our cars doesn't provide Emissions Ready status; only the much pricier system used by dealers/shops can do that.

However, I had already owned a OBDLink MX reader, that I got for connecting to my 2017 Ford pickup. It plugs into the car's OBD port, and then connect via Bluetooth to your phone. I discovered it has a Emissions Readiness screen, which shows the 4 "generic" parameters that must be set before an emissions test station can validate the car.

Here's a link to the tool (also available on Amazon): https://www.obdlink.com/products/obdlink-mxp/

To be honest, I'm currently in the waiting period for getting our Cayman S through emissions testing. About a month ago, before I learned about "drive cycle" and the OBDLink tool, I cleared the CEL with my Durametric, drove it 150 miles over about a week. And when I planned to take it for testing, the CEL came back on. I've confirmed the OBDLink tool sees the emissions data, and I was even able to clear the CEL. Now the 4 parameters show waiting. I'm planning to do the drive cycle soon, to confirm if the parameters turn green, at which point I'll immediately take it for testing.

I hope this is helpful. It's been a good edumacation for me.

[Modian]

I’ve heard the drive cycle can be a little finicky to get right so everything goes into ready state. It is also possible to have a dealer use PIWIS to force the monitors to be ready. At least on the 996 it is, so I assume the cayman too.

Then, maybe they could also do the emissions test.

[matt de maria]

Two things to realize here:
One, The testers are very ignorant. I had one look for my cadillac converter under the drivers door of my 911.
Two, there are 2 major areas that the obd system has to pass. The first is that there has to be no codes that are active. These include o2 sensors, fuel trims etc. (Basically anything that is continuosly monitored that when failed will cause an increase in emissions by 50%) The second area is for non-continuos monitors. These are test that are performed at least every key cycle or timed periodically. Supplementary air injection, evap system, catalyst efficiency etc. Before the year 2000 you are allowed 2 non continuos monitors to not set (pass) The year 2000 onward you are allowed one to not set (pass). However for the stat of maryland the evap test has to pass. I believe that in a clumsy way this is what the tester is trying to get across to you.

[Racer29]

My Audi did the same thing.....be sure you have at least a half tank of gas. Drive normally , no cruise control approximately 100 miles.... That should do it,

[Goggles Paesano]

Everyone is correct in saying the computer has to reset after the codes are cleared. In other words all the monitors have to become active again. what you may face though is the CEL returning before you get back to emissions if the original issue wasn't resolved, but only cleared.
On another note... I was once in line at emissions with a perfect running car and no CEL's. Like an idiot, I thought I would double my chances of passing by scanning and clearing the OBD2 port while in line. Lesson learned because I had just cleared all the monitors and had to go back after 2 weeks basically like what you are going through. D'oh!

[Lara]

I appreciate everyone's insights. Could the tire pressure monitors not being connected, which causes that "code" affect the test???

[Vicegrip]

No. The OBD11 system has to see enough varied running data to be "ready" This is to prevent someone from simply clearing all the codes while waiting in line. TPMS should not throw an emissions failing code. You have to drive it enough both in distance and variables to put the OBD11 system back into "ready" mode.

[tbernard]

Getting a ODBII reader takes all the guess work out of if you are going to pass or not. I always hook up my reader and check before going to the testing station.

A reader like this can be used to read the "Ready" state of the I/M. My 993 was a pain to become ready, the drive cycle was very finicky and without a reader I would have never known if the car was in a "ready" state or not. Took several drive cycles for things to become "Ready"

https://www.amazon.com/Autel-MS309-U..._t1_B0743X5WV8