Porsche P-80 2005, Руководство пользователя

Страница: 57 / 108

Sports Cars System
Climate Control Systems Diagnosis & Repair
Page 3.23
Information Transmitted via the CAN Interface –
Sports Cars M.Y. 2005 - on
The system communicates the following climate
relevant operating and ambient conditions via the
CAN interface:
• Outside temperature (via CAN from the front end control
unit)
• Coolant temperature
• Vehicle speed (to assess the fresh air intake
temperature)
• Engine speed
• Request ’Defrost rear windshield/door mirrors’ (status
on/off via CAN on the vehicle electrical system control
unit)
• Cabriolet top open/closed
• Sun sensor
• Dimming (from instrument cluster)
• Wipe/wash signal
• Request ’Seat heating left’ (status: on/off via CAN on
the vehicle electrical system control unit)
• Request ’Seat heating right’ (status: on/off via CAN on
the vehicle electrical system control unit)
• Interior temperature (actual temperature via CAN to
vehicle electrical
system control unit)
• Request - a/c compressor (status on/off via CAN on the
DME engine
control unit)
• Pressure signal (indirect request for condenser cooling
through provision of coolant pressure via CAN)
• A/C shutdown (e.g. high and low pressure shutdown)
• Diagnosis
• Stationary period since “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 comfort of
driver)
Diagnosis
Diagnosis with the PIWIS Tester is carried out via the
CAN interface (diagnosis socket). Further key
functions are available via the diagnosis interface:
• Readout and erasure of fault memory
• Output of measurement and operating data (e.g. actual
values)
• Actuator control
• Coding
• Calibration processes
Fault Detection
The system incorporates a self-diagnosis facility which
continuously monitors certain functions of the control unit
or system components and records faults in a non volatile
fault memory (EEPROM).
Parameter Possible Fault Location Default Values
Outside temperature Sensor/front-end control unit 50° F. (10° C.)
Interior temperature Sensor/air con. control panel 72° F. (22° C.)
Footwell temperature Sensor 122° F. (50° C.)
Engine temperature Sensor/engine control unit 176° F. (80° C.)
Sun intensity Sensor 150 W/m 2
Speed Sensor/PSM 43 mph (70 km/h)
Engine speed Sensor/engine control unit 1000 rpm
Sensor Default Values
As on the previous 911 Carrera (996) and Boxster/S (986) models, in the event of a short-circuit or interruption of a sensor
default values are employed to maintain operation of the a/c control system in emergency mode.