‒ Press ⇒key.
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Indicated on display
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Desired function
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Fault remedy
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DANGER: Fan is switched on
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- Info display
IMPORTANT
Radiator fan -V7 is switched on when ⇒button is next pressed.
Do not reach into the fan area.
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AC magnetic clutch -N25
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- Air conditioner magnetic clutch -N25 clicks in
2 sec. cycle, the compressor is driven.
Operating and display unit -E87 output is switched from 0 V to 12 V in 2 sec. intervals.
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- Use current flow diagram to check the power supply for magnetic clutch -N25 (via control unit -J293).
Repairing the air conditioner magnetic clutch -N25
().
Use current flow diagram to check the wiring between -E87,-F129, -J293 and -N25.
Renew operating and display unit -E87.
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(cont.)
▼
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Indicated on display
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Desired function
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Fault remedy
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Radiator fan -V7 is also actuated.
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- Fan -V7 (1st speed) is
switched on and off at 2 sec. intervals.
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- Use current flow diagram to check the wiring between -E87 and radiator fan control unit -J293 for open circuit or short to positive.
Check actuation of fan -V7 from control unit -J293 1).
=> Current Flow Diagrams, Electrical Fault-Finding and Fitting Locations
Check functionality of control unit -J293 (=> Electrical check, Page 01-128).
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Notes:
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◆ Radiator fan -V7 is automatically switched on together with the magnetic clutch in vehicles with pressure switch for air conditioner -F129.
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◆ Control unit -J293, installed in vehicles with high-pressure sensor -G65, is available in 2 designs.
- In design "1" the radiator fan is automatically switched on in conjunction with the compressor (the first fan speed is activated regardless of the pressure in the refrigerant circuit).
- In design "2" the compressor is switched on without actuation of the radiator fan; the first
fan speed is only activated once the pressure in the refrigerant circuit exceeds 12 bar.
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◆ The radiator fan is switched to 2nd speed by control unit -J293:
- when thermoswitch -F18 is closed.
-when AC pressure switch -F129 (switch between the contacts 3 and 4) is closed.
- as soon as a refrigerant circuit pressure in excess of 16 bar is calculated by -J293 on the basis of a signal from high-pressure sensor -G65.
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◆ In vehicles with map-controlled cooling the radiator fans are switched on and off by the engine control unit dependent on the refrigerant temperature.
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◆ In vehicles with 8l KW diesel engine and 132 KW petrol engine the engine control unit fans are also activated dependent on the refrigerant temperature or after switching of the ignition (as radiator fan runout).
=> Relevant Workshop Manual Injection and Ignition system; Repair group 01
Notes:
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◆ Only check this output "Air conditioner compressor cut-in" in the event of a complaint (check ).
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◆ In operating and display units with two displays the output "air conditioner compressor cut-in" is connected to connector -C- contact -12-.
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◆ With operating and display units with one display the output "air conditioner compressor cut-in" is connected to connector -C- contact -1-.
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◆ The "ECON key" is the key with the frost symbol in the model of the -E87 with two displays.
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◆ The engine control unit uses the "AC compressor cut-in" signal to compensate for the brief increase in engine load when the compressor is switched on.
=> Relevant Workshop Manual Injection and Ignition system
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◆ The air conditioner compressor can be switched off by the engine control unit and/or control unit for automatic gearbox -J217 via the output/input ("Air conditioner compressor cut-in") (=> Reading measured value block, Page 01-86 display group 01, Injection and Ignition system Workshop Manual and Automatic Gearbox Workshop Manual).
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◆ To test, e.g. read out measured value block of ignition and injection system control unit with engine running while switching the compressor on and off (by actuating the "key with frost symbol") or connect test box V.A.G 1598.
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Indicated on display
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Desired function
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Fault remedy
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Two-way valve for refrigerant shut-off valve -N147
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- The two-way valve -N147 is switched on and off in 2 second intervals.
The refrigerant shut-off valve closes and opens in 2 second intervals (blocks the flow of refrigerant through the heat exchanger of the air conditioning unit).
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- Wiring between -N147 and -E87 for open circuit or incorrect installation according to current flow diagram.
Check two-way valve -N147 (=> Electrical check, Page 87-53)
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Notes:
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◆ The control element "two-way valve -N147" is only activated with an operating and display unit -E87 with one display which is coded to an engine with map- controlled engine cooling.
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◆ The "two-way valve -N147" is only installed into vehicles with map-controlled engine cooling.
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Indicated on display
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Desired function
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Fault remedy
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Fresh air blower -V2
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- Fresh air blower -V2 is actuated for 2 secs. at a time at 0 V, 3 V, 6 V, 9 V, 12 V, 15 V, 0 V, etc.
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- Check freedom of movement of the fresh air blower.
Use current flow diagram to check the earth connection to fresh air blower control unit -J126.
Check control unit -J126 (=> Electrical check, Page 01-128).
Renew operating and display unit -E87.
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Temperature sensor blower -V42
(with an operating and display unit -E87 with one display)
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- Blower -V42 (for temperature sensor installed into -E87) is switched on and off in 5 sec. Switching intervals on or off (smoke is sucked up by blower) 1).
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- Check intake frame and intake hose for blockage ().
Renew operating and display unit -E87.
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1) Check function of blower -V42, using for example, smoke test, (hold smoke source in front of the intake frame installed into the operating and display unit).
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Indicated on display
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Desired function
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Fault remedy
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Temperature flap positioning motor -V68
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- Positioning motor -V68 moves from stop to stop (fresh air blower is operating, air recirculation mode).
Air temperature from the vents changes.
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- Check wiring between -V68 and -E87 for open circuit or incorrect installation according to current flow diagram.
Check freedom of movement of the temperature flap.
Check positioning motor -V68 (=> Electrical check, Page 01-128).
Renew operating and display unit -E87.
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Indicated on display
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Desired function
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Fault remedy
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Central flap positioning motor -V70
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- Positioning motor -V70 moves from stop to stop (fresh air blower operating, air recirculation mode, temperature flap set to "cold").
Air distribution switches between footwell and dash panel vents.
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- Check wiring between -V70 and -E87 for open circuit or incorrect installation according to current flow diagram.
Check freedom of movement of the central flap.
Check positioning motor -V71 (=> Electrical check, Page 01-128).
Renew operating and display unit -E87.
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Footwell/defroster flap positioning motor -V85
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- Positioning motor -V85 moves from stop to stop (fresh air blower operating, air recirculation mode, temperature flap set to "cold").
Air distribution switches between footwell and defrost.
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- Check wiring between -V85 and -E87 for open circuit or incorrect installation according to current flow diagram.
Check freedom of movement of footwell/defroster flap.
Check positioning motor -V85 (=> Electrical check, Page 01-128).
Renew operating and display unit -E87.
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Indicated on display
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Desired function
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Fault remedy
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Air flow flap positioning motor -V71 1)
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- Positioning motor -V71 moves from stop to stop (fresh air blower operating, temperature flap set to "warm", air distribution to windscreen).
Air throughput changes (air flow flap), air conditioner switches between fresh air and recirculated air mode (recirculated/fresh air flap)
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- Check wiring between -V71 and -E87 for open circuit or incorrect installation according to current flow diagram.
Check freedom of movement of air flow flap and fresh/recirculated air flap.
Check positioning motor -V71 (=> Electrical check, Page 01-128).
Renew operating and display unit -E87.
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Temperature sensor blower -V42
(with an operating and display unit -E87 with two displays)
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- Blower -V42 (for temperature sensor in the dash panel) is switched on and off in 5 sec. intervals
(smoke is drawn in by blower) 2).
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- Use current flow diagram to check the wiring between -V42 and operating and -E87 for open circuit or short to earth.
Use current flow diagram to check power supply for -V42.
Check intake frame and intake hose for blockage ().
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1) This positioning motor also controls the recirculated/fresh air flap in addition to the air flow flap.
2) Check function of blower -V42, using smoke test, for example (hold smoke source in front of the intake frame in the centre part of the dash panel).
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Indicated on display
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Desired function
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Fault remedy
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Segment test
(with an operating and display unit -E87 with two displays)
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- All segments of operating and display unit -E87 are switched on and off in 3-second intervals.
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- Renew operating and display unit -E87.
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Ambient temperature indicator -G106 (in the auto-check system)
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- The ambient temperature display (in auto-check system) counts in ascending order starting at -45 °C or°F (approx. 3 sec. per step).
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- Use current flow diagram to check the wiring between the auto-check system and -E87 for open circuit or short circuit.
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Segment test
(with an operating and display unit -E87 with one display)
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- All segments of the display of the operating and display unit -E87 are switched on and off at 1 second intervals.
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- Renew operating and display unit -E87.
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Note:
With operating and display units with one display the ambient temperature display -G106 are activated before the segment test.
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Indicated on display
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Desired function
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Fault remedy
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Idling speed regulation 1)
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- The operating and display unit -E87 output is switched from 0V to 12V at 5 sec. intervals (check ).
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Heated rear window -Z1
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- The heating of the rear window is switched on once for 10 seconds
The rear window is heated near the heating wires.
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- Check control and power intake of heated rear window -Z1 =>Electrical testing, Page 87-71
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End
(only with an operating and display unit -E87 with one display)
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End of final control diagnosis
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1) Depending upon the vehicle equipment, when the rear window heating is switched on, a positive signal is applied to this output (switch off heated rear window for the test).
=> Current Flow Diagrams, Electrical Fault-Finding and Fitting Locations
Starting the "idling speed control" final control diagnosis.
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‒ Switch off ignition.
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‒ Remove engine control unit and connect test box V.A.G 1598 adapter cable to engine control unit connector (do not connect engine control unit to test box).
=> Relevant Workshop Manual Injection and Ignition system; Repair group 01
Note:
-
◆ Pin assignment on connector to engine control unit
=> Current Flow Diagrams, Electrical Fault-Finding and Fitting Locations
=> Relevant Workshop ManualInjection and Ignition system; Repair group 01
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‒ Switch ignition on.
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‒ Switch off rear window heating.
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‒ Connect fault reader V.A.G 1551,
Enter address word 08 "Electronic climate/heating control" and advance the program until "Select function XX" appears on display => Page 01-11.
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‒ Switch on printer by pressing PRINT key (lamp in key lights up).
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