Radiator cooling fan problem? - Crasher/a8 tech - can you help?

Hi,

The problem I have isn't so much the cooling fan, but the sensor side of it.

The cooling fan (the larger of the 2 fans) comes on at all times, ie 1 minute after starting the engine or at any part of the journey. I have replaced the sensor but it still does it.

I was wondering if any other Touran owner had experienced this fault ?

Any advice would be really appreciated.

Thanks, Dave

Touran 1.9 TDi

when this happens are you using the a/c?, if you are, then that is normal, don't know why but my sharan does it .

Hi Andy,

No, the air con isn't on. Its the large fan that comes on (I think the smaller one is for the air con) theres a sensor in the radiator hose that triggers the fan, this I have changed, but its made no difference.

I could do with knowing if theres a seperate ECU that controls the cooling fan ?
Also is it a single speed or dual speed ? and at what resistance does the sensor have to be at to trigger the fan to start ?

Any help or pointers would be great.

Thanks,
Dave

Bumping up for the new title to get some views

Dave, can you PM me your cars reg number?

I suspect that the radiator fan control unit J293 is faulty and you will need a new fan set to cure this which is part number 1K0 998 455 or 1K0 998 455 A and both are just under £200. To identify which set your car needs you will have to give your reg or chassis number to your VW dealer.

Quote:

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Originally Posted by TouranDave

Hi,

The problem I have isn't so much the cooling fan, but the sensor side of it.

The cooling fan (the larger of the 2 fans) comes on at all times, ie 1 minute after starting the engine or at any part of the journey. I have replaced the sensor but it still does it.

I was wondering if any other Touran owner had experienced this fault ?

Any advice would be really appreciated.

Thanks, Dave

Touran 1.9 TDi

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Hello Dave,i would add that the air con pressure switch may trigger the 2 stage fan if it is faulty giving out a false high pressure reading.
Disconect the air con switch and bridge it to eliminate it(refer to a wiring diagram)or check in air con measured values what pressur reading you are getting.

Measured values 62 to 64 in engine management will be of great use to see the temp at the thermostate and at the radiator also a/c and fan duty cycle on/off time.

Also carry out a output test to the fans to determine the fan control units operation,the fans should cut in and out every 5 seconds whilst the test is running.

Also check measured value 3 in air con.
Look at values 2 and 3 for fan amperage and activation of the fan

So Dave you should be able to determine if you are getting inputs to the fan when you shouldnt be or if the fan has a high resistance causing the fan to operate unregulated or no input to the fan control unit but the fan control unit is giving the fan output which would localise the fault to the fan control unit.
The engine ecu will duty cycle the fan control unit which will switch the outputs from the fan control unit to energise the fan as will air con send a comand to the engine ecu which will then forward to the fan control unit.
I dont have any vw wiring diagrams but thats roughly how i would go about it.
If you dont have vag com but you have osciloscope you will be able to check the input


The fan control unit switches the magnetic clutch and, with it, the compressor on and off. It switches the radiator fans and calculates the pressure in the refrigerant circuit on vehicles with high-pressure sender -G65-

Thanks Guys for your very welcome advice.

a8 tech, you have given me loads to get my teeth into, I do have vag com but have very little knowledge of how to use it, but I'm going to try and work through your recommended checks and hopefully pick it up as I go!

I'll let you both know what my findings are.

Dave

Right, I've had a look using vag com,

I checked the measured values in the engine module which gave me various temperature readings (but it didn't tell me where they were taken from, I might be able to work it out) I also did the output test on the fan, it tested the larger fan, which went OK.

But, I couldn't check the Air con measured values, as I don't seem to have a Air con module ? unless I'm not looking in the right place ? Any ideas ?

I'm going to see if I can locate the air con pressure switch and check that side of things.

Thanks, Dave

address 08 should be air con


;
; VAG-COM Label File
;
; Seat Altea/Toledo (5P) / Seat Leon (1P) / Skoda Octavia II (1Z)
; VW Caddy (2K) / VW Eos (1F) / VW Golf/Jetta (1K) / VW Touran (1T)
;
; Component: J255 - A/C Heating Electronics (#08) - Climatronic
;
; P/N: 1K0-907-044-???
;
; includes measuring blocks and basic setting
;
; This file is part of a redirection package,
; make sure you have all of the following files.
;
; 1P-08.LBL
; 1Q-08.LBL
; 1T-08.LBL
; 1Z-08.LBL
; 5P-08.LBL
; 1K0-907-044.LBL
;
; created on 23/Mar/2005 by Sebastian Stange (Sebastian@Ross-Tech.com)
;
; last modification: 15/Jun/2006
;
; requires VAG-COM 603.4 or newer
;
;
;---------------------------------------------------
;
; measuring block information
;
;---------------------------------------------------
;
;
001,0,General
001,1,Compressor,Shut-Off Code,Specification: 0 = Compressos ON\n\nSee Label File
001,2,Engine Speed
001,3,Vehicle Speed
001,4,Standing Time
;
B001,0,
B001,1,
B001,2,
B001,3,
B001,4,
;
002,0,Compressor
002,1,Compressor,Current (actual)
002,2,Compressor,Current (specified)
002,3,Compressor,Rotations
002,4,Compressor Load
;
003,1,Coolant,Pressure
003,2,Radiator Fan,Activation (actual)
003,3,Radiator Fan,Activation (spec.)
003,4,Engine Speed,(increase)
;
004,0,Temperatures
004,1,Outside Temp.,Unfiltered,Display Range: -50...+63 °C
004,2,Outside Temp.,Regulation,Display Range: -50...+77 °C
004,3,Fresh Air Intake,Temperature,Display Range: -40...+60 °C
004,4,Coolant,Temperature,Display Range: -48...+126 °C
;
005,0,Outlet/Footwell Blower Temperature
005,1,Left Outlet Blower,Temperature,Display Range: 0...84 °C
005,2,Right Outlet Blower,Temperature,Display Range: 0...84 °C
005,3,Left Footwell,Blower Temp.,Display Range: 0...84 °C
005,4,Right Footwell,Blower Temp.,Display Range: 0...84 °C
;
006,1,Evaporator,Temperature
006,2,Interior,Temperature
006,3,Left Sunlight,Intensity (G107),W/m²
006,4,Right Sunlight,Intensity (G134),W/m²
;
007,1,Turbine Voltage,(actual),Display Range: 0.0...13.0 V
007,2,Turbine Voltage,(specified),Display Range: 0.0...13.0 V
007,3,Turbine Load,,Display Range: 0.0...100.0 %
007,4,Voltage,(Terminal 30)
;
008,1,Voltage,(Terminal 15)
008,3,Dimming,(Terminal 58d),Display Range: 0.0...100.0 %
008,4,Country,,0 = Rest of World (RoW)\n2 = North America (NAR)\n5 = Japan
;
009,0,Rear Window Heater (Z2) && Aux. Heater
009,1,Rear Window,Heater (Z2 / Actual)
009,2,Rear Window,Heater (Z2 / Spec.)
009,3,Aux. Heater,Status,Display Range: ON/OFF
009,4,Aux. Heater,Current
;
010,1,Aux. Heater,Request,Display Range: ON/OFF
010,2,Heater OFF,,Display Range: ON/OFF
010,3,Back-Up Lights,,Display Range: ON/OFF
010,4,Front Wiper,,Display Range: ON/OFF
;
011,0,Air Recirculation Flap Control Motor (V113) / Potentiometer (G143)
011,1,Current Value
011,2,Specified Value
011,3,Minimum Position,(Lower Stop/Close)
011,4,Maximum Position,(Upper Stop/Open)
;
012,0,Left Temperature Flap Control Motor (V158) / Potentiometer (G220)
012,1,Current Value
012,2,Specified Value
012,3,Minimum Position,(Lower Stop/Close)
012,4,Maximum Position,(Upper Stop/Open)
;
013,0,Right Temperature Flap Control Motor (V159) / Potentiometer (G221)
013,1,Current Value
013,2,Specified Value
013,3,Minimum Position,(Lower Stop/Close)
013,4,Maximum Position,(Upper Stop/Open)
;
014,0,Center Flap Control Motor (V70) / Potentiometer (G112)
014,1,Current Value
014,2,Specified Value
014,3,Minimum Position,(Lower Stop/Close)
014,4,Maximum Position,(Upper Stop/Open)
;
015,0,Defroster Flap Control Motor (V107) / Potentiometer (G135)
015,1,Current Value
015,2,Specified Value
015,3,Minimum Position,(Lower Stop/Close)
015,4,Maximum Position,(Upper Stop/Open)
;
016,0,Air Flow Flap Control Motor (V71) / Potentiometer (G113)
016,1,Current Value
016,2,Specified Value
016,3,Minimum Position,(Lower Stop/Close)
016,4,Maximum Position,(Upper Stop/Open)
;
017,2,Roof Status,,0 = Closed\n1 = Moving: Opening\n2 = Open\n3 = Moving: Closing
;
080,0,Advanced Control Module Identification I
;