lawrence1

every time you disconnect the battery, clear fault codes in the DME, or re-flash the DME, a full emission readiness drive cycle is required in order to set the emission monitors to a "Ready" state. The monitor readiness does not get "resolved" at the smog station - the drive cycle needs to be completed by you. Each car brand and model has different parameters that you must replicate while driving, sometimes in a specific sequence, in order to complete the cycle. It is not mileage driven so those smog techs that tell you drive 500 miles either don't know the specific drive cycle for the car and are telling you to go drive it hoping the monitors will set, or are idiots.

That said, there is no reason to go to the smog station unless all monitors set to "ready" or "completed". Even the cheapest OBD II readers will show you I/M (aka emissions monitor) readiness.

Last but not least, not all aftermarket software will trigger a checksum error, so as long as none of the monitors are showing "incomplete" or "not ready", one can pass even with an aftermarket tune. Passing a visual with aftermarket exhaust modifications is another story. Do keep in mind that Porsche has far more sophisticated equipment at its disposal, and should a warranty claim ever present itself, they will know whether the car was tuned, even if you flashed it back to stock before taking it to the dealer.

d93

When I got my 991.2 GTS smoked they guys at the shop didn't know where to look to see if there were any aftermarket parts or if the cats were present. I didn't get the impression that they really cared to much abut being an enforcement arm for the DMV. They plugged it in, ran it for a few minute and I was on my way.

dreaming

Quick question here: When you say "removed the Cobb tune" do you mean you used the Cobb AP to re-install the backup that was taken when you first installed the AP, or did you do something more drastic like go to Porsche and ask to have ECU reflashed to stock? I think you did the former.

Next question is do we know if the shop was using the new checksum protocol? I think the answer is we don't, but curious if it came up somehow.

I appreciate you sharing your experience!

moswissa

The AP can completely uninstall cobb like nothing ever happened. You can also flash to a stock map but to be safe, its best to remove it completely as having a flashed ECU may hinder the OBD2 readiness

SoCalC4S

Spoke with Cobb a few weeks ago and they have a CARB approved tune in the works it has already been submitted to CARB and im sure they will offer an update to those of us in CARBifornia. I personally am waiting for the new approved version to come out so i do not have to deal with installing and uninstalling multiple times. I can wait a few months.

Need4S

You can and should use an OBD II test scanner to check readiness of the I/M monitors before a smog check. Not all ordinary driving will reset them. They will definitely not show ready if the battery recently has been disconnected or you recently got a check engine light. Scanners only cost about $40 or so. You don’t want a history of failed tests, or else at some point, you car will be flagged for having to go to a Star Certified smog check station, instead of any station convenient to your house. An Ancel AD310 is just one simple scanner for about $35 on Amazon.

If the monitors don’t all show ready, here is the reset procedure I found on the net. Be careful not to get into an accident! The drive cycle is not normal driving. You must start with a cold engine, preferably having the car sit overnight.

”Porsche 911 Drive Cycle - OBDII Emission Monitor Reset Procedure Prior to starting the driving cycle ensure your Porsche's fuel tank is between 1/4 and 3/4 full. Also do not exceed 3,000 rpm or 60 mph during any portion of the drive cycle. Take extra caution when perform the Porsche drive cycle on public roadways. if you think you will be unable to safely perform the drive cycle please seek assistance from an experienced Porsche mechanic or smog check repair center.

A. Start your Porsche 911 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 automatic Tiptronic transmission, idle in drive (D) for 3 minutes. Adaptation range (2) is now being tested.

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

The thing about the checks for OEM ecu firmware is that you can’t test for it using a reader like you can for OBD monitor readiness. So you don’t know if yours will be read by the smog check machine or not. To be safe, restore the OEM firmware and do a drive cycle. I’m looking forward to a CARB-certified Cobb tune to avoid having to do this re-flash every two years.

Greg D.

Gawd....that is exactly the same sequence as old E46 BMWs ! Must be a german ECU thing ! I had my M3 fail smog for a disconnected battery (replaced) and had to do all that - the hard part is the 40-60 mph for 15 minutes and almost got killed in the process, getting passed by busses etc... in the case of the bimmer - so I'm adding this here just in case - you also cannot exceed 3000 rpm on that 40-60 mph drive ! no fun ! The bimmer indicated that it was not ready for ODB test (had I thought of checking) so you can tell if the drive cycle worked or not... Have not tried on the Porsche !

LeJerk

California makes you do emissions testing TWICE A YEAR??

Wow that sounds like a pain in the ***. What a waste of time.

misterioso

No, actually the emissions test schedule for California is much the same as Colorado. New vehicles are not required to be tested for the first 8 years; In the 8th year, the car is subject to biennial testing.

Need4S

Once every two years, not twice a year.

Live Steam

I'm curious about this. My indie, who is gold certified by Porsche, says he cannot detect a tune. How can the DMV detect it? Even if the tune increases carbon emissions and fail the test, there's no way they can claim it's tuned from what I was told.