Notes On Refrigerant Circuit
On vehicles with a high voltage system (hybrid vehicles)
Observe all of the additional warnings for all work performed on vehicles with the high voltage system. Refer to HIGH VOLTAGE VEHICLES SAFETY PRECAUTIONS and HIGH VOLTAGE SYSTEM GENERAL WARNINGS for Hybrid .
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.
Handling high voltage cables:
- 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.
- The round high voltage connectors are color coded with an external color ring and are mechanically coded using the guide- or code tabs. Always make certain that the coding matches when connecting the round connector in order to avoid any mechanical damage 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 Electrical 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 covers 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.
If it is necessary to perform work in the vicinity of high voltage components, perform a "visual inspection" of the high voltage components and cables for damages (refer to PERFORMING A VISUAL INSPECTION OF DAMAGE TO HIGH VOLTAGE COMPONENTS AND CABLES ) and follow the "warnings when working on the high voltage system". Refer to HIGH VOLTAGE SYSTEM GENERAL WARNINGS for Hybrid .
If it is necessary to perform work on the high voltage system components, de-energize the high voltage system. Refer to HIGH VOLTAGE SYSTEM, DE-ENERGIZING and read and follow the HIGH VOLTAGE SYSTEM GENERAL WARNINGS for Hybrid .
The A/C Compressor Control Module -J842- integrated in the electrically-driven A/C compressor regulates the blower speed and therefore the A/C compressor output (Electrical A/C Compressor -V470-).
For vehicles without a high voltage system
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 -N25-, 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 A/C compressor is confronted with a fixed resistance (sealed circuit).
An A/C compressor with an A/C Clutch -N25- is installed as a running change on certain 4-Cylinder vehicles from MY 2012. Refer to BELT PULLEY, REMOVING AND INSTALLING, A/C COMPRESSOR WITH A/C Clutch -N25- . The A/C clutch turns off the A/C compressor drive completely under certain conditions (for example "ECON"). The correct Climatronic Control Module -J255- version must be installed and coded correctly so that the A/C Clutch -N25- can be activated by the Climatronic Control Module -J255- display and control head. Using the Vehicle Diagnostic Tester in the "Guided Fault Finding" function.
To stop the A/C compressor being destroyed when the refrigerant circuit is empty, it is designed such that delivery is reduced to roughly 0% and lubrication is maintained by way of an internal oil circuit with the oil left in the A/C compressor.
All vehicles
Refrigerant in refrigerant circuit is never to be topped up (drain, evacuate and refill circuit). Refer to USING SERVICE STATION .
Replacement compressors contain the full quantity of refrigerant oil required for the refrigerant circuit. Refer to REFRIGERANT R134A CAPACITIES, REFRIGERANT OIL AND APPROVED REFRIGERANT OILS .
Different refrigerant oils are required for A/C compressors made by Denso, Sanden and Zexel/Valeo. Refer to REFRIGERANT R134A CAPACITIES, REFRIGERANT OIL AND APPROVED REFRIGERANT OILS .
Coat the O-ring seals lightly with refrigerant oil prior to installation. Refer to REFRIGERANT CIRCUIT SEALS .
The specified diameters for O-rings and the tightening torque pertain also to the threaded connections of the refrigerant lines or refrigerant hoses between the separate components.
Only install O-ring seals that are suitable for use with refrigerant R134a. Refer to REFRIGERANT CIRCUIT SEALS , and A/C SYSTEM, GENERAL INFORMATION .
Check the cooling output. Refer to COOLING OUTPUT, CHECKING .
Check the pressures in the refrigerant circuit. Refer to USING SERVICE STATION .
All additional refrigerant circuit servicing and test procedures that are not described in this repair information. Refer to A/C SYSTEM, GENERAL INFORMATION .
Operate the A/C system after filling the refrigerant circuit. Refer to A/C SYSTEM, STARTING OPERATION AFTER FILLING REFRIGERANT CIRCUIT .
From the start of production up to the changeover from MY 2012, evaporators approximately 40 mm wide (block depth) were installed (A/C unit part number "8K_ 820 005"). From MY 2012 as a running change, an evaporator with an approximately 50 mm width (block depth) is being installed depending on the vehicle version (A/C unit part number "8T_ 820 005"). Pay attention to the correct allocation of the expansion valve to the evaporator (there are different versions).