A/C System, Operating After Filling Refrigerant Circuit
A/C System, Operating after Filling Refrigerant Circuit
With high voltage systems (hybrid vehicles)
Read and follow all of the supplemental warnings for all work performed on vehicles with the high voltage system.
Risk of unintended engine start
The ignition must be turned off and the ignition key must remain outside of the vehicle when working on vehicles with a high voltage system.
How to handle high voltage cable:
• Do not stand on or place tools on high voltage cables and their components as it may damage the cable insulation.
• Never bend or kink high voltage cables forcefully as it may damage the cable insulation.
• Color-code the round high voltage connector with an external color ring and code them mechanically using the guide- or code tabs. Always make certain that the coding matches when connecting the round connector in order to avoid mechanically damaging the high voltage connector.
There is a risk of electrocution from damaged high voltage components
Observe the following when working around high voltage components and high voltage wires:
• Never work around high voltage components and cables with cutting, deformed, or sharp edged tools, or heat sources such as welding or soldering tools, heated air, and thermal glue.
• Inspect the high voltage components visually before beginning.
• Perform a visual inspection of the electric drive power and control electronics (JX1) , the electro-drive drive motor (V141) , the A/C compressor (V470) and the high voltage lines when working in the engine compartment.
• Perform a visual inspection of the high voltage lines and the cover when working on the underbody.
• Perform a visual inspection of the high voltage lines and the Electrobox with the high voltage system maintenance connector (TW) when working in the luggage compartment.
• Perform a visual inspection on all of the potential equalization cables.
Observe the following items when performing the visual inspection:
• The components do not display any signs of external damage.
• The high voltage cable insulation and the potential equalization cables are not damaged.
• The high voltage cables do not display any abnormal deformations.
• Every high voltage component is marked with a red warning label.
• After the installation of the electrically driven A/C compressor and the subsequent filling of the refrigerant circuit, start up the A/C compressor for the first time using the "compressor intake" function for the basic setting. The A/C compressor may otherwise become damaged if before installation, refrigerant oil was improperly stored in the A/C compressor compression chamber. Refer to Vehicle Diagnostic Tester in the "Guided Fault Finding" Function for A/C System and Battery Regulator.
• Only activate the electrically driven A/C compressor when the refrigerant circuits is filled. Damage to the A/C compressor may occur if the A/C compressor is running while the refrigerant circuit is empty. Refer to Vehicle Diagnostic Tester in the "Guided Fault Finding" Function for A/C System and Battery Regulator.
• All removed parts are installed.
• The refrigerant circuit is filled.
- Switch on the ignition.
- Check the Climatronic control module (J255) display and control head DTC memory and erase any displayed malfunctions if necessary. Refer to Vehicle Diagnostic Tester under "Guided Fault Finding".
- Operate the electric A/C compressor (V470) using the function "Compressor Cut-In". Refer to Vehicle Diagnostic Tester in the "Guided Fault Finding" Function for the A/C System and Battery Control.
• Note the information regarding operating the A/C system after filling.
Without a high voltage system
• Only start engine after refrigerant circuit has been assembled.
• If possible, start engine only with a filled refrigerant circuit.
• Do not start the engine while evacuating the refrigerant circuit or when the circuit is already evacuated (the A/C compressor could be damaged).
• The A/C compressor without an A/C clutch (N25) is always driven when the engine is running. If the vehicle has an A/C compressor without an A/C clutch, then the vehicle may only be started when the refrigerant circuit has been properly assembled. For example; if the refrigerant lines are not connected to A/C compressor, when the engine is running the A/C compressor may heat up (via internal heat generation) so much that the A/C compressor will be damaged. Such internal heat generation results from the fact that - even with delivery near 0% - the compressor is operating with a fixed resistance (sealed circuit).
• An A/C compressor with an A/C clutch is installed as a running change on certain 4-cylinder vehicles from MY 12. Refer to => [ Belt Pulley with A/C Clutch (N25) Overview ] Belt Pulley With A/C Clutch (N25) Overview. The A/C clutch turns off the A/C compressor drive completely under certain conditions (for example "ECON"). The correct Climatronic control module (J255) must be installed and it must be coded correctly so that the Climatronic control module display and control unit can control the A/C clutch. Refer to the Electronic Parts Catalog (ETKA) and to the Vehicle Diagnostic Tester under "Guided Fault Finding".
• The A/C compressor without an A/C clutch is always driven by the belt pulley or driveshaft. To prevent damage when the compressor is idling, it is lubricated by an "internal oil circuit".
• The compressor has an "internal oil circuit" to ensure the A/C compressor is not damaged when refrigerant circuit is empty. Prerequisite for the internal lubrication is residual refrigerant oil in A/C compressor.
• A/C Compressor Regulator Valve (N280) is not activated when the refrigerant circuit is empty and the A/C compressor idles with the engine. As there is no refrigerant in the circuit the oil required to lubricate is not fed to the A/C compressor.
• All removed parts are installed.
If it is necessary to start the engine with a discharged refrigerant circuit:
• Refrigerant circuit must be fully assembled.
• There must be no vacuum in the refrigerant circuit.
• At least 1/4 of the prescribed refrigerant oil must be in the A/C compressor.
• Do not rev engine higher than 2500 rpm.
• The engine should only run as long as is absolutely necessary.
Note the following when starting engine for first time after filling refrigerant circuit:
- Switch on the ignition.
- Check the Climatronic control module (J255) display and control head DTC memory and erase any displayed malfunctions if necessary. Refer to Vehicle Diagnostic Tester under "Guided Fault Finding".
- Start engine with the A/C compressor switched off ("Econ" operating mode set, indicator light in AC button does not light up), and wait until engine idle speed has stabilized.
- Open all instrument panel vents.
- Set the temperature preset on the A/C Control Head Climatronic Control Module (J255) to "cold" (for the driver and passenger side).
- Press the AC button to switch on the A/C compressor ("Auto" mode selected and the indicator light in the AC button is on) and let the engine and A/C compressor idle for at least 5 minutes.
• Note the information regarding operating the A/C system after filling.