How to manually reset the urea system on a Mercedes GL350?

[MacMadelyn]

This requires specialized computer equipment for reset; otherwise, it cannot be reset and may affect the number of engine starts in the future. It is best to go to a 4S shop for reset as soon as possible. The specific introduction of Mercedes GL350 is as follows: 1. Power performance: The 3.0L V6 BlueTEC turbocharged diesel engine represents the most advanced technology in clean diesel engines, certified as ultra-low emissions. It delivers 240 horsepower and 455NM of torque. Mercedes-Benz has improved the original engine technology, including noise reduction, odor and emission enhancement technologies, and the injection of AdBlue solution to reduce nitrogen oxide emissions in the exhaust. 2. Safety: The vehicle is equipped with 13 airbags, including a comprehensive advanced airbag system with dual front airbags (front and side), driver knee airbag, second-row side curtain airbags, and third-row curtain airbags.

[LaAxel]

Last time I drove the GL350, I also encountered the urea warning light coming on. Manual reset isn't actually difficult. First, make sure the ignition is on but don't start the engine. Then locate the control button on the left side of the steering wheel - the one used to adjust the dashboard menu. I usually press the left/right buttons to find the 'Trip' option, then long-press the return button for about three seconds to enter engineering mode. At this point, select 'Actual Values', find the AdBlue-related option, and confirm the reset. However, note that some model years require entering a service code for reset, which you typically need to get from a dealership or professional repair shop. After resetting, remember to drive on the highway for about half an hour to let the system re-monitor. If the warning persists, it might be a sensor issue or clogged nozzle. It's best to buy a urea tester to regularly check the concentration, as running low on urea can trigger speed limitation which is particularly troublesome.

[LaReid]

I've been repairing Mercedes-Benz for about seven or eight years, and manually resetting the GL350 urea system actually involves two methods. The most reliable way is to use a diagnostic tool to access the engine module for reset. If you don't have the equipment, try the engineering menu. First, close the door and fasten your seatbelt, turn the key to the second position without starting the engine. When the odometer is displayed on the dashboard, simultaneously press the phone button and the OK button on the steering wheel for five seconds. Then, select 'ASSYST PLUS workshop' from the hidden menu, navigate to 'Actual values,' and find the AdBlue reset option. However, newer models require the Star Diagnostic tool, and older models will fail to reset without entering the authorization code. After resetting, you must drive the vehicle for at least 20 minutes to allow the system to self-learn. Additionally, check for urea tank crystallization and nozzle blockages, as these are the root causes of most issues.

[VanSienna]

Manual reset can be done in three simple steps. First, turn on the power but do not start the engine. Then, use the steering wheel buttons to access the instrument menu, navigate to the maintenance section, and find the AdBlue reset option. If available, entering the hidden engineering mode makes the process even easier—for newer models, look for the service function reset in the vehicle settings. Before resetting, ensure the urea level is sufficient and the concentration meets standards. If the warning persists despite adequate levels, the NOx sensor likely needs replacement. Many car owners overlook the road test after resetting—it's crucial to drive the vehicle until it reaches operating temperature and covers sufficient distance for the system to update data. If the reset fails, the ECU might be locked, in which case you should promptly visit a 4S shop to read the fault codes.

[CamilaLynn]

Every GL350 diesel owner knows the frustration of the urea warning light. I've dealt with it three times already. First, check the dashboard to see how many kilometers you have left before the system locks you out—if it's under 1,000 km, address it immediately. The key to manual reset is accessing the engineering menu: With the engine off, hold the steering wheel return button and OK button for ten seconds until you hear a beep, then release to enter the special menu. Select the engine module to find the urea reset option. Procedures vary by model year—pre-2012 versions use button combinations, while post-2015 models require using the touchpad to navigate subsystems. I recommend keeping an OBD scanner handy; for around $20, you can monitor real-time urea data. After resetting, always refill with genuine urea—low-quality urea causes crystallization that destroys the system.

[Evelyn]

Actually, the urea system reset for Mercedes is relatively straightforward. First, ensure the urea tank is full, then sit in the driver's seat, fasten the seatbelt, and close the door. Turn the key to the ignition-on position, use the directional buttons to navigate to the left instrument menu's trip interface. Simultaneously hold down the phone hang-up button and the OK button for five seconds to access the hidden menu. Here, locate the special functions item for the engine control unit. When selecting the AdBlue reset, you may need to enter an authorization code—older models might accept the code 0000. The most crucial step is to drive continuously after the operation; stop-and-go city driving won't suffice. You must drive on the highway for at least 20 minutes to allow the system to learn the new data. If the warning light keeps coming on, check the post-treatment system wiring.