Safety Precautions

Safety Precautions

Note the following when working on the fuel system:


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

• To reduce pressure in fuel system, lay a clean cloth around the connector and carefully loosen connector.

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 electrical connectors were disconnected, faults are saved in the ECM:

- Connect the vehicle diagnosis, testing and information system (VAS 5051B).

- Start "Guided Functions" operating mode.

- Generate readiness code in ECM.


Risk of destroying electronic components when disconnecting the battery.

• Observe measures for disconnecting battery.

• Only disconnect the battery with ignition switched off.

- 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.

If testing equipment must be used during a road test, observe the following:


Distraction and testing equipment that is not secured properly can cause accidents.

Risk of the passenger airbag deploying in an accident.

• Operating testing equipment while driving causes it to shift position.

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

• Always secure testing equipment on the rear seat using a strap and have a second person in the rear seat operate it.