On-board diagnostic interface

If you connect equipment to the on-board WARNING
If you connect equipment to the on-board diagnostics interface, it can affect the operation of the vehicle systems. This can impair the operating safety of your vehicle while driving. There is a risk of accident.
Do not connect any equipment to the onboard diagnostics interface.

Loose equipment or equipment cables which WARNING
Loose equipment or equipment cables which are connected to the on-board diagnostics interface can obstruct the area around the pedals. The equipment or the cables could get between the pedals in the event of sudden braking or acceleration. You may then no longer be able to brake, operate the clutch or accelerate as intended. There is a risk of accident.
Do not attach any equipment or cables in the driver footwell.

Connecting equipment to the on-board diagnostics interface can lead to emissions monitoring information being reset. This may lead to the vehicle failing to meet the requirements at the next special emissions test or main inspection.

If the engine is switched off and equipment on the on-board diagnostic interface is used, the starter battery may discharge.

The on-board diagnostics interface is only intended for the connection of diagnostic equipment at a qualified specialist workshop.

    See also:

    Switching off the engine
    Important safety notes WARNING   Do not turn off the engine before the vehicle has come to a complete stop. With the engine not running, there is no power assistance for the brake and s ...

    General notes
    The Active Driving Assistance package consists of DISTRONIC PLUS (Y page 169), Active Blind Spot Assist (Y page 202) and Active Lane Keeping Assist (Y page 205). ...

    High outside temperatures
    If DEF heats up to over 122 °F (50 °C ) for extended periods, e.g. as a result of direct sunlight on the DEF reservoir, DEF can decompose. Ammonia vapors develop as a result. WARNING When o ...