We understand your Porsche 911 GTS is having difficulty getting its emission monitors (readiness flags) to complete. Typically driving your Porsche for a few hundred miles over the course of a few days (in both city and highway traffic conditions) is enough to get the emission monitors ready for the smog test. Sometimes however the driving pattern required to complete the emission monitors are not met during normal city/highway driving, and following the required and specific Porsche drive cycle/pattern is needed.
Below we outline the driving cycle you'll need to perform in order to get your Porsche's OBD-II emission monitors to become READY or COMPLETE, and pass the smog check. Perform the entire drive cycle. Completing only one portion of the drive cycle will not make the particular monitor which you're trying to make READY complete. The entire drive cycle must be performed every time you attempt to set any of the monitors.
Porsche 911 Drive Cycle - OBDII Emission Monitor Ready Driving Pattern
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. They will be able to complete the drive cycle in-house and on a dynamometer. Perform the drive cycle at your own risk.
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. You must not make any stops and starts during this step. 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.
Should the Catalyst Monitor and/or the Oxygen Sensor Monitor not complete after completing the drive cycle a few time, we'd recommend having your vehicle inspected by either a Porsche dealer repair center or reputable smog check test and repair 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 the 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. It's possible that neither of these two conditions trigger the check engine light to turn on, but they will stop the drive cycle from making the required monitors ready. Having an auto repair shop attempt to complete the drive cycle in-house will allow them to monitor all system parameters while the drive cycle is in progress. They can pinpoint what may be causing your Porsche's emission monitors to not set.
