Vehicle Front and Engine Compartment Components
Vehicle Front and Engine Compartment Components
1 Sunroof (with Solar Cells (C20) )
• Only in vehicles with this optional equipment.
• Check the function of the solar cells, refer to => [ Sunroof Solar Panel ] Sunroof Solar Panel.
• The activation and operation of the fresh air blower (V2) by the fresh air blower control module (J126) depends on the sunlight, the MMI (Multi Media Interface) setting, and the Climatronic control module (J255). Refer to => [ Sunroof Solar Panel ] Sunroof Solar Panel and Operating instructions.
2 Heated Windshield (Z2)
• Only in vehicles with this optional equipment.
• Activation is performed via the windshield defogger control module (J505) (installed in the luggage compartment on the left next to the battery) - item 5 => [ (Item 5) ] Vehicle Rear and Luggage Compartment Components.
• The windshield defogger control module is activated by the Climatronic control module (J255) via the data bus. For this purpose, the request is first sent via the data bus to the data bus on board diagnostic interface (J533) and is then relayed to the comfort system central control module (J393). Refer to and Vehicle Diagnostic Tester in the "Guided Fault Finding" function.
• Refer to => [ Windshield Defogger ] Windshield Defogger.
3 Fresh Air Intake With Intake Grille
• Check cowl panel trim with the cover for the fresh air intake for correct installation and damage. Check the seals between the fresh air intake cover, the cowl panel trim and the window cross member for damage and proper fit. This seals prevent water from entering between window cross member and cover and running into A/C unit air intake shroud.
• Checking, removing and installing, refer to => [ Fresh Air Intake ] Service and Repair.
• Make sure the intake grille fits correctly. The intake grille prevents foreign objects such as leaves from getting into the A/C intake shroud.
• Depending on the version, a filter is installed instead of intake air grille, which prevents dust and sand from entering the fresh air blower. Refer to => [ Fresh Air Intake ] Service and Repair and the Electronic Parts Catalog (ETKA).
4 Air Quality Sensor (G238) with Humidity Sensor In Fresh Air Intake Duct (G657)
• In this vehicle the Air Quality Sensor and Humidity Sensor In Fresh Air Intake Duct are combined in one component.
• Function of the air quality sensor and humidity sensor in fresh air intake duct, refer to => [ Air Quality Sensor (G238) ] Description and Operation or => [ Humidity Sensor In Fresh Air Intake Duct (G657) ] Humidity Sensor In Fresh Air Intake Duct (G657).
• Check the Air quality sensor and humidity sensor in fresh air intake duct. Refer to => [ Air Quality Sensor (G238), Checking ] Air Quality Sensor (G238), Checking and => [ Humidity Sensor In Fresh Air Intake Duct (G657), Checking ] Humidity Sensor In Fresh Air Intake Duct (G657), Checking.
• Removal and installation, refer to => [ Air Quality Sensor (G238) With Humidity Sensor In Fresh Air Intake Duct (G657) ] Service and Repair.
• The measured value of the Air quality sensor and humidity sensor in fresh air intake duct is evaluated by the vehicle electrical system control module (J519) and is transmitted via the data bus to the Climatronic control module (J255). Upon request, the Climatronic control module switches to recirculation mode if no shut-off condition is present. Check using the Vehicle Diagnostic Tester in the "Guided Fault Finding" function.
5 Label
• With specifications for type of refrigerant and designated fill capacity. R134a Servicing 00 Specifications.
6 Heater Coolant Shut-Off Valve (N279)
- Not available in the NAR market
- The Heater coolant shut-off valve is currently only installed in vehicles with a parking heater.
7 Coolant Recirculation Pump (V50)
• The coolant recirculation pump is currently not installed in all vehicles.
• Checking function, refer to => [ Heat Output and Temperature Door Activation, Checking ] Heat Output and Temperature Door Activation, Checking.
• Removing and installing, refer to => [ Coolant Recirculation Pump (V50) ] Coolant Recirculation Pump (V50).
• Integration in the coolant circuit, refer to => [ Incorporation of A/C System in Coolant Circuit ] Incorporation of A/C System in Coolant Circuit.
• The installed location of the coolant recirculation pump varies. For most vehicles, it is installed in the plenum chamber as shown in the illustration.
• The activation of the coolant recirculation pump varies. For most vehicles, the Climatronic control module (J255) is activated directly by the front Climatronic control module A/C display and control head.
8 Coolant Shut-Off Valve (N82)
• Depending on the engine, the coolant shut-off valve is installed in the coolant feed and return line from the engine to the heater core.
- The shut-off valve is currently only installed on certain engines.
• Activation, removing and installing, refer to => [ Coolant Shut-Off Valve (N82) ] Coolant Shut-Off Valve (N82).
• Refer to => [ Incorporation of A/C System in Coolant Circuit ] Incorporation of A/C System in Coolant Circuit.
9 Parking Heater With the Auxiliary Heater Control Module (J364)
• Only in vehicles with this optional equipment.
• Not available in the NAR market.
10 Coolant Fan (V7) and Coolant Fan 2 (V177)
• Different versions of the coolant fan and coolant fan 2 are installed depending on the vehicle equipment. Refer to the Electronic Parts Catalog.
• The request to switch on the coolant fan/coolant fan 2 is sent by the Climatronic control module (J255) , via the data bus to the engine control module. The engine control module then activates the fan(s) (coolant fan and coolant fan 2) directly or via the Coolant fan control module (J293).
• Check the activation of the coolant fans by the Climatronic control module using the Vehicle Diagnostic Tester in the "Guided Fault Finding" function.
• The respective engine control module switches, for example, the coolant fan and the coolant fan 2 (directly or via the coolant fan control module) continuously without stages to the desired output (depending on engine type). Refer to and the Vehicle Diagnostic Tester in the "Guided Fault Finding" function.
11 Outside Air Temperature Sensor (G17)
• The measured value of the outside air temperature sensor is evaluated by the vehicle electrical system control module (J519) and is transmitted via the data bus to the Climatronic control module (J255). Refer to and the Vehicle Diagnostic Tester in the "Guided Fault Finding" function.
• Removal and Installation, refer to => [ Outside Air Temperature Sensor ] Outside Air Temperature Sensor (G17).
12 Plenum Chamber Water Drains
• Two water drains are installed on the left and right in the plenum chamber.
• Removing and installing, checking and cleaning, refer to => [ Plenum Chamber Water Drain ] Service and Repair.