Safety Precautions

Safety Precautions

Note the following when working on the fuel system:


There is a risk of injury because the fuel is under very high pressure.

• Reduce the fuel pressure down to residual pressure before opening high pressure area of the fuel injection system.

• To reduce remaining residual pressure, place clean cloth around the connector and carefully loosen connector.

- Procedures before opening high pressure fuel injection system.

To prevent personal injury and damage to the injection and ignition system, observe the following:

• Turn off the ignition before disconnecting and connecting the wiring for the injection and ignition system. This includes tester cables as well.

• Only clean engine with ignition switched off.

• If the connectors were disconnected and the engine was started, then malfunctions have been stored in the engine control module DTC memory: "Generate readiness code" in Guided Functions .


Danger of causing damage to electrical components when disconnecting the battery.

• Complete the steps for disconnecting the battery.

• Turn off the ignition and disconnect the battery.

- Disconnect the battery.

Note the following when working on the cooling system:


Risk of scalding due to hot steam and hot coolant.

• The coolant system is under pressure when the engine is warm.

• Cover the coolant reservoir cap with a cloth and then open it slowly to release the pressure in the system.

Risk of injury from coolant fan starting by itself.

• Before working in fan shroud area, disconnect electrical connectors.


The vehicle could overheat if the cap is installed incorrectly.

• The cap must engage noticeably when sealing.

When working on a vehicle with the Start/Stop System, note the following:


Danger of serious personal injury if the engine starts automatically on vehicles with the Start/Stop System.

• If the Start/Stop System is activated (message in the instrument cluster), the engine can start automatically.

• Make sure the Start/Stop System is deactivated whenever working on the vehicle. Switch off the ignition and switch it on only when necessary.

If it is necessary to use testing and measuring devices on road tests, observe the following:


Distraction and improperly secured test equipment can lead to accidents.

There is a risk that the passenger airbag could deploy in a collision.

• Operating testing and measuring equipment while driving creates a distraction.

• There is an increased risk of injury due to unsecured testing and measuring equipment.

• Always secure testers on the rear seat with a strap and have a second person on the rear seat to operate them.

Note the following when working on the exhaust system:


Danger of damaging the decoupling element.

• Decoupling element must not be bent more than 10°.

• Do not load decoupling element on cable.

• Do not damage wire mesh at decoupling element.