Is your Mercedes-Benz check engine light stubbornly staying on? Before you rush to the mechanic, you might be able to reset your OBD2 system and clear those pesky codes yourself. This guide will walk you through a specific drive cycle designed to reset your Benz OBD2 monitors, potentially turning off that check engine light and getting your car ready for an emissions test.
Highway Drive Cycle for Benz OBD2 Reset
This drive cycle is a series of specific driving maneuvers that can help your Mercedes-Benz’s onboard diagnostic system complete its self-tests. Successfully completing this cycle can set all your OBD2 monitors to “READY,” indicating that your emission system is functioning correctly. It’s crucial to perform this cycle precisely as described, starting with a cold engine.
Here’s the step-by-step highway drive cycle for your Benz:
- Initial Idle and Gentle Acceleration: Start your Mercedes with a cold engine. Let it idle for 20 seconds. Then, gradually accelerate and drive at a speed between 20-25 mph for 1 minute, slightly varying your speed within this range.
- Moderate Speed and Deceleration: Drive at 25-31 mph for 35 seconds. Afterward, decelerate to 0 mph over a period of 10 seconds. Let the car idle again for 40 seconds.
- Varied Speed Driving: Accelerate moderately and drive at 20-25 mph for 20 seconds. Increase your speed to 40-55 mph for 85 seconds. Then, decelerate to 0 mph over a longer period of 50 seconds. Idle for 15 seconds.
- 36 mph and Quick Stop: Accelerate to 36 mph in 35 seconds. Decelerate to 0 mph in just 15 seconds. Idle for 10 seconds.
- 30 mph Acceleration and Deceleration: Accelerate to 30 mph and then decelerate back to 0 mph over a 25-second period. Idle for 20 seconds.
- 36 mph Drive and Stop: Accelerate to 36 mph in 20 seconds. Drive at a steady 35 mph for 20 seconds. Decelerate to 0 mph in 15 seconds. Idle for only 5 seconds.
- 26 mph Acceleration and Deceleration: Accelerate to 26 mph and decelerate to 0 mph in 40 seconds. Idle for 15 seconds.
- 27 mph and Quick Stop: Accelerate to 27 mph in 40 seconds. Decelerate to 0 mph in just 8 seconds. Idle for 25 seconds.
- 26 mph and Deceleration: Accelerate to 26 mph and decelerate to 0 mph in 35 seconds. Idle for 15 seconds.
- Stop and Go Traffic Simulation: Drive in stop-and-go traffic conditions for 1 minute. During this minute, reach speeds of 25-30 mph twice, without coming to a complete stop.
- Varied 20-30 mph Driving: Drive at 20-30 mph for 2 minutes, varying your speed. Stop. Then, drive at 20-28 mph for 2 and a half minutes at varying speeds. Stop again and idle for 30 seconds.
- 28 mph and 20 mph Segments: Accelerate to 28 mph and decelerate back to 0 mph in 50 seconds. Then, accelerate to 20 mph in 10 seconds, drive at 20-27 mph for 20 seconds, and decelerate to 0 mph in 10 seconds. Idle for 15 seconds.
- 23 mph and 22 mph Segments: Accelerate to 23 mph and decelerate back to 0 mph in 20 seconds. Idle for 10 seconds. Accelerate to 22 mph and decelerate back to 0 mph in 45 seconds. Idle for another 10 seconds.
- 25 mph Drive and Quick Stop: Accelerate to 25 mph in 30 seconds. Drive at 23-28 mph for 25 seconds. Decelerate to 0 mph in less than 10 seconds.
- Final Idle and Acceleration: Idle for 25 seconds. Accelerate to 22 mph and decelerate back to 0 mph in 30 seconds.
Repeat this entire 15-step cycle two times for the best chance of resetting your Benz OBD2 monitors.
If this highway drive cycle doesn’t set your monitors to “READY”, there is also a 15-step city drive cycle available which might be more suitable for your Mercedes-Benz model. Consult your vehicle’s repair manual or a professional mechanic for further assistance and to diagnose any underlying issues that may be preventing your monitors from resetting. This process is intended to help your vehicle complete its self-tests; it does not fix mechanical problems. If your check engine light persists, it’s important to get a proper diagnosis to ensure your Mercedes-Benz is running optimally and to address any potential emissions concerns.
