Getting your Porsche 996 ready for an emissions test after a service can be tricky. Disconnecting the battery resets the OBDII system, requiring you to complete a drive cycle to set all readiness monitors. This guide outlines the OBDII readiness procedure for the Porsche 996.
Understanding OBDII Readiness Monitors
OBDII readiness monitors are self-diagnostic tests that constantly evaluate various emission control systems in your 996. When the battery is disconnected, these monitors are reset to “not ready.” A certain number of monitors must be in the “ready” state before an emissions test can be performed.
Porsche 996 Drive Cycle Procedure
While a specific drive cycle procedure for the 996 is often cited, it can be challenging to execute precisely. This procedure generally involves specific speeds, durations, and RPM limits:
- Cold Start: Start the engine cold and let it idle for approximately 2 minutes and 10 seconds.
- Acceleration and Steady Speed: Accelerate to 20-30 MPH and maintain a steady speed for around 3 minutes and 15 seconds.
- Higher Speed Cruise: Accelerate to 40-60 MPH and maintain a steady speed for about 15 minutes. This step often proves difficult in real-world driving conditions.
- Deceleration and Idle: Decelerate to a stop without using the brakes heavily. Idle in gear for roughly 5 minutes.
Practical Tips for Setting Readiness Monitors
Following the precise procedure can be challenging. A more practical approach involves a combination of driving conditions:
- Warm-up: Start the engine cold and allow it to idle until the idle smooths out and the engine reaches operating temperature.
- Varied Driving: Incorporate a mix of city driving with stop-and-go traffic, highway driving at moderate speeds (under 60 MPH and preferably below 3500 RPM), and some boulevard cruising.
- Monitor Progress: An OBDII code reader with readiness monitor viewing capabilities can track the status of each monitor. This allows you to monitor progress without guessing. Avoid clearing codes after resetting the check engine light, as this will restart the process.
Pre-Emissions Test Checklist
Before heading to the emissions testing facility:
- Warm Engine: Ensure the engine is fully warmed up. Drive the car for at least 20-30 minutes using the varied driving approach described above.
- Avoid Shutting Off: Keep the engine running while waiting for the test. This prevents the monitors from resetting.
Conclusion
Preparing your Porsche 996 for an emissions test after battery disconnection requires completing a drive cycle to set the OBDII readiness monitors. While a specific procedure exists, a more practical approach involving varied driving conditions is often more effective. Using an OBDII code reader and following the pre-emissions checklist will increase your chances of passing the test.
