Dealing with smog check failures can be a frustrating experience for any car owner. Often, after a service or battery disconnect, your vehicle’s computer system needs to complete a “drive cycle” to reset its emissions monitors. If these monitors are not ready, your car will fail the smog test, even if there are no underlying mechanical issues. One common scenario is encountering incomplete Catalyst and Evap monitors, preventing you from passing inspection. This was exactly the situation I faced, and after some trial and error, I found a solution using the Autel Autolink Al319 Obd2 Scanner Automotive Engine tool.
Initially, following advice to simply take a long drive seemed like the straightforward answer. I drove over 200 miles, navigating various roads, but unfortunately, the monitors remained incomplete. This led me to realize a more targeted approach was necessary. That’s when I decided to invest in an OBD2 scanner to understand what was truly happening with my vehicle’s system. After a quick search, the Autel AutoLink AL319 OBD2 Scanner from Walmart became my tool of choice.
The key to completing a drive cycle isn’t just about mileage; it’s about following a specific set of driving conditions that allow your car’s computer to run all the necessary diagnostic checks. I discovered a detailed OBD2 drive cycle procedure online and decided to follow it precisely. This particular drive cycle emphasizes condition-based completion rather than just distance. It’s crucial to perform this cycle accurately, ideally over two consecutive days.
Here’s the drive cycle I followed, and it needs to be executed exactly as described:
OBD2 Drive Cycle Procedure:
Important Notes Before Starting:
- Perform Twice: This drive cycle should be performed twice on consecutive days for best results.
- Road Conditions: For the final phase, you’ll need a straight, safe road where you can maintain a steady 35 mph without interruption. Avoid traffic, excessive throttle, and do not lift off the throttle completely.
Steps:
- Ignition On: Turn the ignition to the “ON” position for 30 seconds (do not start the engine).
- Check for DTCs: Use the Autel AutoLink AL319 OBD2 Scanner to check for Diagnostic Trouble Codes (DTCs).
- Coolant Temperature: Ensure the engine coolant temperature is below 140°F (60°C) before starting.
- Start Engine and Idle: Start the engine and let it idle for 2 minutes.
- Light Accelerations: Perform two light accelerations from 0 to 35 mph using light pedal pressure.
- Medium Accelerations: Perform two medium accelerations from 0 to 45 mph using moderate pedal pressure.
- Hard Accelerations: Perform two hard accelerations from 0 to 55 mph using heavy pedal pressure.
- 60 mph Cruise: Cruise at 60 mph for 5 minutes.
- 50 mph Cruise: Cruise at 50 mph for 5 minutes.
- 35 mph Cruise: Cruise at 35 mph for 5 minutes.
- Engine Idle: Let the engine idle for 2 minutes.
- Check for DTCs Again: Use the Autel AutoLink AL319 to check for DTCs again.
Critical Considerations:
- Do Not Turn Off Car: Avoid turning off the car in the middle of the drive cycle.
- Avoid Air Conditioning: Keep the air conditioning off during the procedure.
For my attempt, I kept the Autel AutoLink AL319 OBD2 scanner automotive engine plugged in from step two onwards to monitor the process in real-time. With a timer in hand, I executed each step during an evening drive. While sticking precisely to the speed during accelerations wasn’t always possible due to traffic, I tried to adhere to the sequence and pedal pressure as closely as I could. The highway cruise at 60 mph was manageable, but the 50 mph segment required a detour to a less busy beachside road to maintain a safe and consistent speed.
The most critical part was the 35 mph cruise. I maintained a speed slightly above 35 mph (around 37 mph) to ensure I didn’t drop below the required minimum. About three minutes into this 35 mph cruise, the Autel AutoLink AL319 OBD2 scanner gave a different beep, indicating the Catalyst monitor had finally completed! Although the Evap monitor remained incomplete, which is often acceptable for smog tests depending on your location’s regulations, my car successfully passed the smog check.
The Autel AutoLink AL319 proved to be an invaluable tool. Its constant beeping as it checks the monitors can be a bit noticeable during the drive, but it provides essential real-time feedback. Remarkably, completing the drive cycle on the first day was enough; a second cycle wasn’t needed in my case.
If you’re facing smog check issues due to incomplete monitors, especially after ECU resets or battery changes, the Autel AutoLink AL319 OBD2 scanner automotive engine and this specific drive cycle procedure can be your solution. It takes patience and precision, but it can save you time and further headaches in getting your vehicle to pass its emissions test.
