General Repair Information
Installed on Vehicles with High Voltage Systems (Hybrid Vehicles)
For all procedures on vehicles with a high-voltage system, pay attention to the additional warnings for these vehicles. Refer to SAFETY PRECAUTIONS WHEN WORKING ON VEHICLES WITH HIGH-VOLTAGE SYSTEM .
For the following procedures work near the high-voltage system components is necessary, "Safety Precautions when Working near High-Voltage Components". Refer to SAFETY PRECAUTIONS WHEN WORKING NEAR HIGH-VOLTAGE COMPONENTS .
Working on a high voltage system when activated or with the ignition turned on
-- To minimize the number of automatic motor starts during the testing and measuring procedures while the ready mode is active, charge the vehicle batteries in battery support mode with the Battery Charger :VAS5904 , for example. Refer to BATTERY, DISCONNECTING AND CONNECTING and SAFETY PRECAUTIONS WHEN WORKING ON THE HIGH-VOLTAGE SYSTEM .
-- Move the selector level into position "P", activate the parking brake and arrange the necessary tools for testing and measuring procedures that require the ready mode to be active or that require the ignition to be on, so that they cannot come into contact with the turning components in the engine and so that they are not in the vicinity of the turning components of a running engine.
Also move the selector lever into position "P" and activate the parking brake for testing and measuring procedures which require the ignition to be on, but do not require the ready mode to be active.
The ready mode is displayed in the Instrument Cluster Control Module -J285- above the "powermeter". Refer to Owner's Manual.
Activate and deactivate the ready mode. Refer to Owner's Manual (consult the display in the Instrument Cluster Control Module -J285-).
-- On vehicles with a high-voltage system, switch off (deactivate) the "auxiliary climate control" function. Refer to the Owner's Manual and Infotainment/MMI Operating Manual.
All Vehicles
Remove the appropriate fuse(s) before working on electrical wires.
Disconnect the battery before performing any electric welding on the vehicle. Refer to BATTERY, DISCONNECTING AND CONNECTING .
The refrigerant circuit for the A/C system may only be discharged and opened when:
- It is necessary due to safety precautions (refer to SAFETY PRECAUTIONS WHEN HANDLING REFRIGERANT ).
- It is necessary to remove other components.
- Refrigerant circuit components for the A/C system must be removed or replaced.
When performing all other usual vehicle repair work, the refrigerant circuit of the A/C system should remain closed.
The connections for the sensors/switches described in this Service Information are fitted with a valve which closes automatically when the switches are unscrewed. These switches can thus be replaced in any workshop even though the refrigerant circuit is fully charged.
If it is necessary to discharge and open the refrigerant circuit for the A/C system for certain repair work on the heating and air conditioning system, this is described in the respective work procedure. Certain tools are required to discharge the refrigerant circuit. These work procedures must only be performed by trained personnel as well. Refer to REFRIGERANT CIRCUIT, DISCHARGING WITH A/C SERVICE STATION (R134a) (Refrigerant R134a Servicing, Refrigerant Circuit, Working with A/C Service Station) and REFRIGERANT CIRCUIT, DISCHARGING (R1234yf) .
If the necessary tools are not available or no qualified personnel is present, do not perform repairs on the refrigerant circuit for the A/C system that require the refrigerant circuit to be discharged and opened. If necessary, the vehicle must be transferred to a workshop that has the necessary tools and equipment and where the work can be performed by qualified personnel. There the refrigerant circuit can be discharged and opened according to the legal specifications. Refer to A/C SYSTEM, GENERAL INFORMATION (R134a) / REFRIGERANT CIRCUIT, DISCHARGING WITH A/C SERVICE STATION (R134a) or LAWS AND REGULATIONS (R1234yf) .