On Board Diagnostic (OBD) - HVAC, Can & Defrosters

• Automatic Climate Control System, On Board Diagnostic (OBD)
  • General information
  • Technical data
  • System changes from m.y. 1998
  • System changes from m.y. 2000 (with revised driver's information display)
  • VAG 1551 ((VAG 1552) Scan Tool (ST), connecting and selecting functions
    • Requirements
  • Diagnostic Trouble Code (DTC) Memory, checking (function 02)
    • Notes
    • If a DTC was recognized
  • Diagnostic Trouble Code (DTC) table
    • Notes
    • Changes to model year 2000 and up vehicles
  • Output Diagnostic Test Mode (DTM) (function 03)
    • Notes
    • Initiating output DTM
    • Changes to model year 2000 and up vehicles:
      • Notes
      • Activated actuators
  • Output Diagnostic Test Mode (DTM) Idle speed control test, initiating
  • Basic Setting (function 04)
  • Diagnostic Trouble Code (DTC) Memory, erasing (function 05)
    • Requirements
  • End Output (function 06)
  • Code Control Module (function 07)
    • Notes
    • Coding variants:
      • Notes
      • Example for A/C control head -E87- up to index "H":
      • Example for A/C control head -E87- from index "J":
      • Coding A/C control head -E87- (up to index "H")
      • Coding A/C control head -E87-, beginning at index "J"
      • Coding A/C control head -E87-, model year 2000 and up
  • Read Measuring Value Block (function 08)
    • Notes
    • Read Measuring Value Block, initiating
    • Overview of display group numbers which can be selected
    • Display group 001 - A/C compressor cut-off conditions, voltage for A/C clutch -N25-, voltage to terminal 15 and requirement for recirculating air mode/sensor for air quality -G238-
    • Display group 002-Defroster flap motor -V107-
    • Display group 003-Left center vent motor -V110-
    • Display group 004-Right center vent motor -V111-
    • Display group 005-Center vent adjusting motor -V102-
    • Display group 006-Temperature regulator flap motor -V68-
    • Display group 007-Left footwell flap motor -V108-
    • Display group 008-Right footwell flap motor -V109-
    • Display group 009-Rear footwell vent motor -V112-
    • Display group 010-Air flow flap motor -V71-
    • Display group 011-Recirculation flap motor -V113-
    • Display group 012-ACF flap motor -V114-
    • Display group 013-Left center air vent switch -F183- and right center vent switch -F184-, center vent position sensor -G142- and calculated ambient temperature for outside air temperature display -G106-
    • Display group 014-Outside air temperature sensor -G17- and fresh air intake duct temperature sensor -G89-, left vent temperature sensor -G150- and right vent temperature sensor -G151-
    • Display group 015-Instrument panel interior temperature sensor -G56-, calculated coolant temperature and sunlight photo sensor -G107-
    • Display group 016-Voltage and fresh air blower -V2-, parking light and voltage at terminal 58D)
    • Display group 017-Engine speed, compressor speed and vehicle speed
    • Display group 018-Kick-down switch, coolant temperature switch, A/C compressor cut-in and A/C refrigerant high pressure switch -F118-
    • Display group 019-Coolant pump -V50-, left heat regulating valve -N175- and right heat regulating valve -N176-
    • Changes to model year 2000 and up vehicles, Overview of display group numbers which can be selected
    • Display group 001: Instantaneous occurring compressor shut off conditions, voltage for A/C clutch, -N25-, Voltage to terminal "15" and requirement recirculation mode/sensor for air quality -G238-
    • Display group 012: For control head having part numbers up to Index "K"
    • Display group 012: Information on Can-Bus for control head having part numbers beginning with the index letter "M"
    • Display group 013: Switch for jet center left -F183- and right -F184-, center vent position sensor -G142- and calculated outside temperature for outside air temperature display -G106-
    • Display group 014: Outside air temperature sensor -G17-, Outside temperature from instrument cluster, fresh air intake duct temperature sensor -G89-, left vent temperature sensor -G150-, and right -G151-
    • Display group 15: Instrument cluster interior temperature sensor -G56-, calculated or determined by coolant temperature transferred into instrument cluster and sunlight photo sensor -G107-
    • Display group 016: Voltage to fresh air blower -V2-, voltage to terminal 58d, terminal 58s and parking light 58
    • Display group 017: engine RPM, compressor RPM, vehicle speed and auxiliary heater
    • Display group 018: Kick-down-switch activating rear window defroster, temperature switch for coolant, A/C compressor engagement and high pressure switch -F118-
    • Display group 019: Left heat regulating valve -N175- and right -N176-; pump for coolant recirculation -V50- and activation of windshield defroster
    • Display group 020: the last four compressor shutoff conditions
    • Display group 021: Idle RPM increase, activating fan for coolant and activating washer system
    • Display group 022: Allocation ignition key and signal for "time ignition off"
• Automatic Climate Control System, electrical tests
  • Tools required
  • Connecting VAG1598/19 test box to connector of A/C control head -E87-
  • Test step 1 - Temperature sensors
    • Notes
    • Resistance levels of temperature sensors dependent on ambient temperature in k ohm (kilo-ohms)
  • Test step 2 - Center vent position sensor -G142-
  • Test step 3 - Fresh air blower -V2- and control module for fresh air blower -J126-
  • Test step 4 - Coolant pump -V50- and related valves
  • Test step 5 - Motors in engine compartment
  • Test step 6 - Motors in passenger compartment
  • Test step 7 - Sensor for compressor speed, low pressure and high pressure switches
  • Test step 8 - Relay for A/C clutch, actuation of fan
  • Test step 9 - Signal for washer/wiper system
  • Electrical test changes for model year 2000 and up vehicles
  • Test step 1 (Voltage supply, Ground, illumination, temperature sensor/sender):
  • Test step 8 (A/C clutch relay -J44-, activating coolant fan -V7-):
  • Test step 9 (Signal for washer-wiper system, connection to windshield defroster control module -J505-):
• Can-Bus
  • Can-Bus, function
    • Bus:
    • Can:
    • Example:
  • Can-Bus malfunction "Faulty databus drive," checking
    • Notes
    • Malfunction is indicated only by A/C control head -E87-
    • In another control module a malfunction is indicated:
    • Can-Bus notes:
    • Malfunction is indicated only by A/C control head -E87-.
• Rear window defroster, electrical test
  • Required measuring and test items
  • Test requirements
• Windshield defroster
  • Windshield defroster, function
  • Windshield defroster, disconnecting
• Solar sunroof, checking
  • Notes
  • Checking function of solar sunroof
• Data Link Connector (DLC), checking wiring connections
  • Notes
  • Tools required
  • Terminal assignment at Data Link Connector (DLC)