Experiencing an “OBDII Not Ready” error during your Mercedes W210 emissions test can be frustrating. Often, this issue arises after a battery replacement, as the car’s computer systems need to recalibrate. Completing an OBDII drive cycle is crucial to reset these systems and ensure your Mercedes W210 is ready for its emissions test. This article outlines the specific drive cycle procedure for your W210 to help you clear those “Not Ready” flags.
Step-by-Step OBDII Drive Cycle for Mercedes W210
To initiate the OBDII drive cycle on your Mercedes W210, begin with a cold start. This means the engine coolant temperature should be below 122 degrees Fahrenheit (50 degrees Celsius), and the ambient air temperature and coolant temperature sensors should be within 11 degrees Fahrenheit (6 degrees Celsius) of each other. Crucially, avoid turning the ignition key to the ‘on’ position before starting the engine, as this may prevent the heated oxygen sensor diagnostic from running.
Phase 1: Initial Idle
Start the engine and let it idle in drive for two and a half minutes. Ensure the air conditioning (A/C) and rear defrost are turned on during this phase. This step allows the OBDII system to check the oxygen sensor heater circuits, air pump, and EVAP purge system.
Phase 2: Acceleration and Cruise
Turn off the A/C and rear defrost. Accelerate to 55 mph (88 km/h) at half throttle. The OBDII system will now assess for ignition misfire, fuel trim, and canister purge.
Phase 3: Steady Speed Monitoring
Maintain a constant speed of 55 mph (88 km/h) for three minutes. During this phase, the OBDII system monitors the EGR system, air pump, oxygen sensors, and canister purge.
Phase 4: Deceleration
Safely decelerate (coast down) to 20 mph (32 km/h) without applying the brakes or depressing the clutch. This allows the OBDII to check the EGR and purge functions during deceleration.
Phase 5: Re-acceleration and Cruise
Accelerate again to 55 to 60 mph (88-96 km/h) at approximately quarter throttle. The system re-checks for misfire, fuel trim, and purge.
Phase 6: Extended Monitoring
Hold a steady speed of 55 to 60 mph (88-96 km/h) for five minutes. This extended phase allows the OBDII system to monitor catalytic converter efficiency, misfire, EGR, fuel trim, oxygen sensors, and purge functions more thoroughly.
Phase 7: Final Deceleration and Stop
Finally, decelerate (coast down) to a complete stop without using the brakes. This final step allows the OBDII system to make a last check of the EGR and canister purge systems.
By carefully following these steps for your Mercedes W210 OBDII drive cycle, you should successfully reset the necessary monitors and prepare your vehicle for a successful emissions test. Remember to perform the drive cycle exactly as described for optimal results.
