Porsche P-80 2005 Manual Download Page 97

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BUS Communications

Climate Control Systems Diagnosis & Repair

Page 6.7

1 - Gateway

2 - Steering Column Switch (with electronic unit)

3 - Vehicle Electrical System Control Unit

4 - Passenger Compartment Roof Control Unit

5 - Rear Convenience System Control Unit

6 - KESSY Control Unit

7 - Air Conditioning System Regulator Control Unit, Rear

8 - Air Conditioning System Regulator Control Unit

9 - Park Assist Control Unit

10 - RDK Control Unit (tire pressure control system)

11 - Memory Seat Adjustment Control Unit, Passenger

12 - Memory Seat Adjustment Control Unit, Driver

13 - Door Control Unit, Passenger

14 - Door Control Unit, Driver

15 - Door Control Unit, left rear

16 - Door Control Unit, right rear

17 - AHK Control Unit

CAN - Comfort/Convenience (CAN-B)

Data transfer rate: 100 K bits/second (100 K baud)
Failure mode: Data transmission remains possible with a
short or open in one bus line.

Summary of Contents for P-80 2005

Page 1: ...AfterSales Training Climate Control Systems Diagnosis Repair P 80...

Page 2: ...Dr Ing h c F Porsche AG is the owner of numerous trademarks both registered and unregistered including without limitation the Porsche Crest Porsche Boxster Carrera Cayenne Tiptronic VarioCam PCM 911 4...

Page 3: ...r Chapter Description Section Introduction i Air Conditioning Basics 1 911 Carrera 993 1995 98 2 Sports Cars 911 Carrera 996 997 Boxster 986 987 3 Cayenne 9PA 2003 0n 4 A C Refrigerant System Service...

Page 4: ...Climate Control Systems Diagnosis Repair...

Page 5: ...sold in North America have A C standard and all US models are equipped with automatic climate control systems With the push of a button today s customer expects rapid heating and cooling Only when th...

Page 6: ...on Dioxide R 134a refrigerant is better but still has a GWP value of 1 300 The discovery of these problems caused the governments of the industrialized world to establish a time table for the reductio...

Page 7: ...ge Air Conditioning Overview 1 3 Principles of Heat Transfer 1 3 The Refrigeration Cycle 1 7 Compressor 1 8 Pressure Relief Valve 1 10 Condenser 1 11 Receiver Dryer 1 11 Evaporator 1 12 Thermostatic E...

Page 8: ...Page 1 2 Climate Control Systems Diagnosis Repair Air Conditioning Basics Notes...

Page 9: ...he evaporator as it removes heat from the passenger compartment Then the refrigerant gas condenses back to liquid in the condenser giving off heat to ambient outside air This is a short description of...

Page 10: ...tes it removes body heat In a similar way refrig erant vaporizing changing from liquid to gas inside the A C evaporator absorbs heat from the warmer air around the evaporator Practical Application In...

Page 11: ...ature of a liquid or gas varies with its pressure The pressure of the refrigerant in the closed A C circuit will vary with changes in temperature and the temperature of the refrigerant varies with cha...

Page 12: ...quid as heat is removed R 134a refrigerant is as a gas at atmospheric pressures and ambient temperatures In the closed refrigerant circuit some refrigerant is in liquid form because of the higher pres...

Page 13: ...used up unless there is a mechanical problem or a leak The amount of heat moved from inside to outside the vehicle determines the heat load Both temperature and humidity affect the heat load The refr...

Page 14: ...ve The system high side contains high pressure refrigerant and includes the compressor outlet condenser receiver dryer and expansion valve inlet The flow of refrigerant gas into and out of the compres...

Page 15: ...iable displacement compressors are more efficient than fixed displacement compressors because they pump only enough refrigerant to achieve the desired cooling Energy is not wasted pumping more refrige...

Page 16: ...d helps to seal moving parts This lubricant is carried by the flow of refrigerant throughout the system and it must be compatible with the refrigerant seals and components Porsche A C systems with R 1...

Page 17: ...fan comes ON to improve airflow and heat transfer Receiver Dryer 911 Carrera 996 Receiver Dryer The receiver dryer is a reservoir for refrigerant on the system high pressure side It is located betwee...

Page 18: ...efrigerant becomes a gas it absorbs both sensible heat and large amounts of latent heat from the cabin air passing through the evaporator fins The refrigerant warms and the cabin air passing over the...

Page 19: ...and pressure in the evaporator Both evaporator inlet and outlet lines pass through the TEV Refrigerant temperature is sensed at the evaporator outlet Increases in evaporator outlet gas temperature due...

Page 20: ...ns 911 Carrera 993 models have A C high and low side service connections located in the rear near the A C compressor 911 Carrera 996 997 and Boxster 986 987 model connec tions are located in the cowl...

Page 21: ...he refrig erant used today It has similar heat transfer properties like R 12 but it does not contain Chlorine R 134a has 84 less global warming potential than R 12 and it does not destroy ozone For th...

Page 22: ...Page 1 16 Climate Control Systems Diagnosis Repair Air Conditioning Basics Notes...

Page 23: ...Repair Page 2 1 Subject Page A C System Description Refrigerant System Description 2 3 Air Distribution System 2 3 Heating A C Control Unit Operation 2 5 Sensors Actuators 2 6 Service and Diagnosis In...

Page 24: ...Page 2 2 Climate Control Systems Diagnosis Repair 911 Carrera 993 Model System Notes...

Page 25: ...left front wheel housing Evaporator The A C evaporator is located in the air distribution housing Evaporator removal requires removal and disas sembly of the air distribution housing Thermostatic Expa...

Page 26: ...s drawn in through the engine air inlet grille by the engine cooling fan Some of this air is pumped to the exhaust heat exchangers by the auxiliary heater blower The auxiliary blower supplies hot air...

Page 27: ...e recirculation switch on the Heater A C Regulator selects the recirculation mode The recirculation mode prevents outside air intake and increases the cooling efficiency of the A C It also prevents un...

Page 28: ...Page 2 6 Climate Control Systems Diagnosis Repair 911 Carrera 993 Model System 911 Carrera 993 Sensors and Actuators...

Page 29: ...re air through the condenser and to reduce high side refrigerant pressure The 3 way pressure switch is installed in the system high side Evaporator Temperature Sensor The evaporator temperature sensor...

Page 30: ...nsors L R Fresh air flap position sensor Defrost flap position sensor Footwell flap position sensor Notes Actuators Compressor Clutch An electromagnetic clutch engages and drives the compressor The cl...

Page 31: ...he auxiliary blower under these conditions Ambient temperature 14 C 11 F and the mixing flaps are allowing max heat Max heat is requested in cold ambient temperatures When no heat is requested in summ...

Page 32: ...al passenger s controls Passengers can select the desired temperature blower speed and air distribution conditions The system will maintain the set temperature as conditions change The Heating A C Con...

Page 33: ...onditions Vehicle speed 0 mph Temperature in one or both mixing chambers 80 C 176 F Auxiliary blower temperature 95 C 203 F Oil temperature 105 C 221 F The System Tester is required for troubleshootin...

Page 34: ...Page 2 12 Climate Control Systems Diagnosis Repair 911 Carrera 993 Model System Notes...

Page 35: ...ibution System 3 5 Regulating Air Temperature 3 6 Control Panel Function 911 Carrera 996 Boxster 986 3 8 Manual Air Conditioning Boxster S 987 3 9 Automatic Climate Control 911 Carrera S 997 Optional...

Page 36: ...Page 3 2 Climate Control Systems Diagnosis Repair Sports Cars System Notes...

Page 37: ...the selected passenger compartment tempera ture The system is capable of maintaining temperatures between 18 29 C 64 84 F with 22 C 72 F recommended In automatic operation the system deter mines and c...

Page 38: ...at load The compressor displace ment is 160 cm3 9 8 in 3 at 100 output Output can be as low as approx 5 Condensers Two A C condensers are used on the 911 Carrera 996 997 and Boxster 986 987 models The...

Page 39: ...t ment The system can add or remove heat from the cabin air and provide ventilation heating cooling and defrost functions On 911 Carrera 996 997 and Boxster 986 987 models the water cooled engine allo...

Page 40: ...by the back pressure which arises in the area of the fresh air inlet according to the vehicle speed In order to compensate for this depen dency the distributor flap for fresh air recirculated air back...

Page 41: ...outside fresh air and inside recirculation air When the fresh air mode is selected outside air is drawn into the vehicle from the intake air duct located in the plenum in front of the windshield All o...

Page 42: ...a 996 Boxster 986 Automatic climate control was standard equipment on 911 Carrera 996 and Boxster 986 models sold in the United States The system automatically maintains temperatures between 18 29 C 6...

Page 43: ...ith integrated control unit in the center console The appearance of the control panel for the manual air conditioning system is based on that of the control panel for the automatic climate control sys...

Page 44: ...re explained in the section on Automatic climate control Air Conditioning Automatic Climate Control Standard on the 911 Carrera S 997 and optional on the Boxster S 987 Functions This air conditioning...

Page 45: ...individually for the left button A and right button G side Apart from OFF level two heating levels can be selected When the appro priate button is pressed the air conditioning control unit control pan...

Page 46: ...ith the window heating to directly control the heating elements for the defrost function of the door mirrors The maximum heating time for the rear window and door mirrors is 15 minutes I Automatic Mod...

Page 47: ...Sports Cars System Climate Control Systems Diagnosis Repair Page 3 13 Sensors and Actuators 911 Carrera 996 Boxster 986 Through M Y 2000...

Page 48: ...r Sports Cars System Sensors and Actuators Sports Cars M Y 2001 on Except Boxster S 987 w Manual A C For 2005 the A C pressure switch was changed by connecting directly to the A C controller line inpu...

Page 49: ...si The medium pressure switch is in the DME circuit to control the condenser fan The DME control unit runs the condenser fan at second speed when the switch contacts close This high fan speed moves mo...

Page 50: ...to the A C Control Unit for interior temperature Interior temperature is sensed and compared with the target temperature requested by the passengers and also ambient tempera tures This comparison infl...

Page 51: ...er Air Control Flap Position Sensors Automatic Climate Control system air control flap motors have feedback position sensors built in The position sensor is a potentiometer which provides an analog si...

Page 52: ...t second high speed when engine coolant temperature exceeds 102 C 216 F Cooling Fans Sports Cars M Y 2005 on The engine coolant radiator and condenser fan speed is controlled by the DME and fan speed...

Page 53: ...ator out of the airstream or with the vehicle fresh air inlet blocked During a cold start the voltage to the fresh air blower is reduced by 50 to prevent the unpleasant discharge of cold air At ambien...

Page 54: ...From M Y 2001 the control unit communicates via low speed comfort CAN to the cluster which then communicates via high speed CAN to the DME The A C Control Unit outputs a pulse width modulated PWM sig...

Page 55: ...n speeds can indicate drain blockage Evaporator fin temperatures cannot be allowed to drop below the freezing point of water If this happens the evaporator can become blocked with ice and airflow can...

Page 56: ...ters are monitored and will set fault codes if defects are found Interface with the instrument cluster Outside temperature sensor Interior temperature sensor Blower outlet sensor Supply Voltage termin...

Page 57: ...ignition off from instrument cluster Steering angle sensor If control module detects lots of steering angle changes it drops the temperature a little without changing the driver s selection for comfo...

Page 58: ...Page 3 24 Climate Control Systems Diagnosis Repair Sports Cars System Notes...

Page 59: ...tem 4 7 Air Distribution Components 4 8 Rear Heating and Cooling Unit 4 8 Auxiliary Park Heater 4 9 Manual A C Operation 4 10 Climate Control Operation 2 Zone 4 11 Climate Control Operation 4 Zone 4 1...

Page 60: ...Page 4 2 Climate Control Systems Diagnosis Repair Cayenne Model System Notes...

Page 61: ...ressor relay the compressor always runs if the engine is running 1 Plug connector electronic control valve 2 Pressure relief valve 3 Connector opening low pressure side 4 Electronic control valve Comp...

Page 62: ...ssure side just in front of compressor near left wheel arch Refrigeration Circuit 2 Zone Climate Control The cold air circulation in the Cayenne is set up so that the compressor and the expansion valv...

Page 63: ...Climate Control Systems Diagnosis Repair Page 4 5 Additional Refrigeration Circuit 4 Zone Climate Control 1 Refrigerant lines for the rear evaporator 2 Line for the heating circulation for the rear h...

Page 64: ...front of the engine coolant radiator and fan Receiver Dryer The receiver dryer on Cayenne models is a replaceable cartridge that is integrated into the right side of the condenser The cartridge can re...

Page 65: ...limate control system the temperature and air volume for the driver and front passenger can be separately adjusted Outlets are located in the instrument panel the rear console and floor vents under th...

Page 66: ...e models have a charcoal particle filter integrated into the air distribution housing The filter is located in front of the evaporator and can be removed for service from the passenger side footwell R...

Page 67: ...the heat source An electric circulation pump non return valve and 3 2 way valve can isolate the park heater from engine coolant The park heater is operated and set from the front control panel of the...

Page 68: ...el The following individual settings can be displayed in the air conditioning display Air flow blower Air distribution Temperature adjustment Time synchronous to PCM or instrument cluster Suppression...

Page 69: ...emperature right side S Air Volume Button right side 4 Zone Climate Control Optional Operation A Defrost Front Windshield B Defrost Rear Window C Auto Button automatic operation REST Button motor resi...

Page 70: ...e Climate Control Unit is located in the dash and has the manual passenger s controls The standard Cayenne automatic climate control system provides 2 zone control while a 4 zone with front and rear c...

Page 71: ...lectable In conjunction with the automatic front 2 zone A C system therefore the interior climate can be controlled for a total of 4 individual zones The settings for the 4 zones can be made on the fr...

Page 72: ...Page 4 14 Climate Control Systems Diagnosis Repair Cayenne Model System 4 Zone Sensors Actuators Rear...

Page 73: ...ses through the evaporator fins The evap orator temperature sensor is located right behind the evaporator The control unit monitors this sensor to prevent condensa tion on the evaporator fins from fre...

Page 74: ...res are sensed by four outlet tempera ture sensors This permits the control unit to monitor outlet air temperatures on the left and right sides separately and to maintain different temperature setting...

Page 75: ...limate Control system air control flap motors have feedback position sensors built in Each position sensor is a potentiometer which provides an analog signal to the Climate Control Unit for flap posit...

Page 76: ...signal to the blower regulator to set the appropriate blower speed The blower regulator is located on the air distribution housing on the right side near the blower A heat sink on the back side of th...

Page 77: ...ther the signal is within range If a sensor circuit fault is detected the system ignores the signal and substitutes a stored default value In this way emergency operation of the climate control system...

Page 78: ...Page 4 20 Climate Control Systems Diagnosis Repair Cayenne Model System Notes...

Page 79: ...ge 5 1 Subject Page A C Refrigerant System Service 5 3 Environmental Impact 5 3 A C Service Equipment 5 3 Equipment Maintenance 5 3 A C Refrigerant System Service Procedures 5 5 A C System Performance...

Page 80: ...Page 5 2 Climate Control Systems Diagnosis Repair A C Refrigerant System Service Diagnosis Notes...

Page 81: ...esponded with changes and improvements to A C systems and service procedures Refrigerant R 12 is no longer produced or installed by manufacturers and R 134a is the only approved refrigerant installed...

Page 82: ...service stations have similar gauges and hand valves They may appear different but in most cases they work the same way Service hoses for R 134a systems have quick connectors and check valves to mini...

Page 83: ...er service station instructions Most service stations will weigh the recovered refrigerant and indicate how much refrigerant was removed Note this value as it can help diagnosis later The recovery pro...

Page 84: ...pened by an accident or has been left open It is unknown whether the system has been open Part of a leak check procedure Refrigerant Recycling A C service stations automatically recycle the recovered...

Page 85: ...turning the A C system ON If this valve is left open the refrigerant storage tank will be exposed to high side pressures and can explode The A C system should be ON continuously for at least two minut...

Page 86: ...y the complaint Checking for stored DTCs will identify suspect components or systems and whether the problem is likely to be electrical or mechanical Pressure gauge readings will help to verify the me...

Page 87: ...nd low side pressure can help to diagnose poor A C performance Remember that the compressor s job is to increase pressure on the high side and reduce pressure on the low side Variable displacement com...

Page 88: ...ngs and cautions before starting diagnosis or repair work Observe the following precautions Automotive air conditioning systems and service equipment are under pressure and refrigerant can spray unexp...

Page 89: ...atures exceed a certain value See Workshop Manual for speci fications For safety most charging stations recharge A C systems by pumping the refrigerant into the system with the compressor not running...

Page 90: ...immediately with large quantities of water and seek medical attention If refrigerant contacts the skin remove the wet clothing and rinse immediately with large quantities of water Seek medical attenti...

Page 91: ...Page 6 1 Subject Page CAN Bus Networking 6 3 Network Architechure 6 4 Bus Logic 6 5 Cayenne Networking 6 6 CAN Drive CAN C 6 6 CAN Comfort Convenience CAN B 6 7 CAN Infotainment 6 8 CAN Internal 6 9 C...

Page 92: ...Page 6 2 Climate Control Systems Diagnosis Repair BUS Communications Notes...

Page 93: ...temperature sensor and related wiring With CAN only one control unit needs to receive temperature input It processes this information and shares it with all units on the bus CAN communication message...

Page 94: ...ge on both wires both lines on the oscilloscope moves up or down together so the voltage difference between CAN High and CAN Low always remains approx 2 Volts This is sometimes called a differential s...

Page 95: ...h CAN High and CAN Low values approx 2 5 Volts to dominant CAN High signal approx 2 Volts higher than CAN Low signal and back to recessive Up to 30 control units can be present on the High Speed CAN n...

Page 96: ...Page 6 6 Climate Control Systems Diagnosis Repair BUS Communications Networking Cayenne Cayenne models use the following networking systems CAN Drive Bus CAN C CAN Convenience CAN B CAN Infotainment...

Page 97: ...Air Conditioning System Regulator Control Unit 9 Park Assist Control Unit 10 RDK Control Unit tire pressure control system 11 Memory Seat Adjustment Control Unit Passenger 12 Memory Seat Adjustment C...

Page 98: ...ainment Data transfer rate 100 K bits second 100 K baud Failure mode Data transmission remains possible with a short or open in one bus line 1 Gateway 2 PCM2 3 Wiper Motor with integrated control unit...

Page 99: ...BUS Communications Climate Control Systems Diagnosis Repair Page 6 9 CAN Internal 1 Combination Sensor 2 PSM Control Unit...

Page 100: ...Left Rear 17 Control Door Right Rear 18 Control Driver s Door 19 Control Front Passenger Door 20 Trailer Control Unit 21 Vehicle Electrical System Control Unit 22 Climate Control Element Front 23 Clim...

Page 101: ...S St te ee er ri in ng g C Co ol lu um mn n C Co on nt tr ro ol l U Un ni it t K Ke es ss sy y C Co on nt tr ro ol l U Un ni it t BUS Communications Climate Control Systems Diagnosis Repair Page 6 11...

Page 102: ...9 Driving authorization control unit PAS 10 Steering column switch control module 11 Sliding roof control unit 12 Rear control unit 13 Vehicle electrical system control unit 14 Tire pressure monitorin...

Page 103: ...BUS Communications Climate Control Systems Diagnosis Repair Page 6 13...

Page 104: ...Page 6 14 Climate Control Systems Diagnosis Repair BUS Communications...

Page 105: ...ETER cc cc CUBIC CENTIMETER X 061 CUBIC INCH FOOTPOUND ft lb X 1 3558 NEWTON METER Nm Nm NEWTON METER X 7376 ft lb FOOT POUND HORSEPOWER SAE X 746 KILOWATT Kw HORSEPOWER DIN X 9861 HORSEPOWER SAE Kw K...

Page 106: ...Page 7 2 Climate Control Systems Diagnosis Repair Conversion Charts Notes...

Page 107: ......

Page 108: ...Part Number PNA P80 001...

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