sitticheep
Member Since: 10 Sep 2009
Location: Thailand
Posts: 11
 
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| How to check and confirm functioning of Electro viscous fan |
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Hi, I live in Thailand where the climate is very hot all year round. The A/C is a must here. My D3 start to have A/C problem it stop cooling whenever the car stop moving eg. red light but not every time. Checked all the A/C component are working find after throughly check found out the Viscous fan in front of the engine stop blowing in fullspeed. It cause the refigerant temp to increase then pressure rise to the level of A/C cooling cycle shutdown. I suspect the cooling fan not functioning properly but "How can I check and confirm this is viscous problem or not?" Anyone had an idea? please....  Or anyone experience the same problem and can point me what went wrong that cause A/C to shutdown?
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 23rd Sep 2009 9:15 pm |
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DG
Site Moderator
Member Since: 12 Dec 2005
Location: The Gaff
Posts: 50936
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Quote:For additional airflow through the radiator matrix, particularly when the vehicle is stationary, there is an engine driven electro-viscous fan unit fitted to the rear of the radiator. The fan is used for engine cooling and for Air Conditioning (A/C) system cooling. This unit functions as a normal viscous fan, but with electronic control over the level engagement of the clutch. The Engine Control Module (ECM), which determines the required fan speed, controls the level of clutch engagement. The ECM determines engagement based on the coolant, charge air, ambient and transmission oil temperatures and the A/C pressure. The fan is mounted using a left hand thread.
The viscous fan unit is electronically controlled by the ECM to optimise fan speed for all operating conditions.
NOTE:
If the electrical connections to the viscous fan are disconnected the fan will 'idle' and overheating may result. The ECM stores the appropriate fault codes in this case.
An early indication of a fan problem will be that your engine will overheat ...does the temperature gauge appear normal ?
Quote:Symptom
Poor or no cooling
Possible causes
Drive belt fault
Compressor fault
Distribution motor/flap fault
Refrigerant leak
In-vehicle temperature sensor fault
Refrigerant pressure sensor fault
Action
Check the drive belt condition and tension (see visual inspection). Check the compressor operation (observe the compressor as the engine is idling with the air conditioning switched on. If the compressor runs erratically or does not run. Carry out the distribution motor self test. Refer to the relevant workshop manual section. Check for sensor DTCs. Refer to the DTC index. Check the refrigerant system using your charging station.
This indicates the scope of what could be wrong. 21 year LR veteran > D2 GS 2003 > D3 S 2006 > D3 HSE 2009 > D4 HSE 2013 > D4 HSE 2015 > D5 HSE 2018 > DS HSE R-Dynamic P300e 2021
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| 23rd Sep 2009 9:35 pm |
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sitticheep
Member Since: 10 Sep 2009
Location: Thailand
Posts: 11
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Hi,
All component checked and found to be no problem. let me describe the work sequence.
Start the engine the fan run for a min or less A/C cooling is normal then with no reason fan slowly down to idle and A/C stop bolwing cool air out but when you begin to move the car up to a speed then cool air come out again but will not immediate need to dirve for 1-2 min before it start cool air.
Test procedure, attached the pressure gauge to high pressure to check refigerant pressue start engine check the pressure it read about 300PSI and voltage check from pressure sensor is about 3V and fan run for a while then fan just slow down within 15 sec the pressure rise to upto 480PSI and volt at the pressure sensor also rise to 4.5V then fall down. (This is the protection process to cut compressor out). So it is confirm that compressor are fine pressure sensor is working and ATC does read a correct and react as it should.
the main issue here is why fan doesn't run all the time when A/C is enable. I found a few time that I start the engine at stationary for an hour without A/C cut off the differenct is fan never stop. I guess the fan doesn't stop because of the engine coolant is hot enough to kick in fan.(but most of the time it stop)I can't diagnose further from this point why fan stop by itself even the cooling cycle are on going when I check with GTR fan only control from ECM. By the way, engine doesn't seem to be overheat. the temp gauge only read a little lower than half all the time.
Any suggest from this point?
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| 24th Sep 2009 1:38 am |
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DG
Site Moderator
Member Since: 12 Dec 2005
Location: The Gaff
Posts: 50936
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Quote:To control the cooling fan, the ECM sends a Pulse
Width Modulated (PWM) signal to the cooling fan
module (integral to the ECM). The frequency of the
PWM signal is used by the cooling fan module to
determine the output voltage supplied to the fan motor.
The ECM varies the duty cycle of the PWM signal
between 0 and 100% to vary the fan speed. If the PWM
signal is outside the 0 to 100% range, the cooling fan
module interprets the signal as an open or short circuit
and runs the fans at maximum speed to ensure the engine
and gearbox do not overheat.
The speed of the cooling fan is also influenced by
vehicle road speed. The ECM adjusts the speed of the
cooling fans, to compensate for the ram effect of vehicle
speed, using the Controller Area Network (CAN) road
speed signal received from the Anti-lock Braking
System (ABS) module.
Quote:For additional airflow through the radiator matrix,
particularly when the vehicle is stationary, there is an
engine driven electro-viscous unit. This unit functions
as a normal viscous fan, but with electronic control over
the level engagement of the clutch. The Engine Control
Module (ECM), which determines the required fan
speed, controls the level of clutch engagement. The
ECM determines engagement based on the coolant,
ambient and transmission oil temperatures and air
conditioning (A/C) system pressure. The fan is mounted
using a left hand thread.
The viscous fan unit is electronically controlled by the
ECM to optimise fan speed for all operating conditions.
Quote:Coolant flows through the radiator from the top right
hand tank to the bottom left hand tank and is cooled by
air passing through the matrix. The temperature of the
cooling system is monitored by the ECM via the Engine
Coolant temperature (ECT) sensor located in the
cylinder head. The ECM uses signals from this sensor
to control the cooling fan operation and adjust fuelling
according to engine temperature.
To control the cooling fan, the ECM sends a Pulse
Width Modulated (PWM) signal to the cooling fan
module (integral to the ECM). The frequency of the
PWM signal is used by the cooling fan module to
determine the output voltage supplied to the fan motor.
The ECM varies the duty cycle of the PWM signal
between 0 and 100% to vary the fan speed. If the PWM
signal is outside the 0 to 100% range, the cooling fan
module interprets the signal as an open or short circuit
and runs the fans at maximum speed to ensure the engine
and gearbox do not overheat.
The ECM operates the fan in response to inputs from
the ECT sensor, the transmission oil temperature sensor,
the A/C switch and the A/C pressure sensor.
The speed of the cooling fan is also influenced by
vehicle road speed. The ECM adjusts the speed of the
cooling fans, to compensate for the ram effect of vehicle
speed, using the Controller Area Network (CAN) road
speed signal received from the Anti-lock Braking
System (ABS) module.
All the info I can find I'm afraid.I don't think it's your fan though to be honest, otherwise you would have general overheating of the engine. Sounds more like a control module. 21 year LR veteran > D2 GS 2003 > D3 S 2006 > D3 HSE 2009 > D4 HSE 2013 > D4 HSE 2015 > D5 HSE 2018 > DS HSE R-Dynamic P300e 2021
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| 24th Sep 2009 7:14 am |
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sitticheep
Member Since: 10 Sep 2009
Location: Thailand
Posts: 11
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Hi,
Thank you for your comment. I'm waiting for my MSV-2 to be activated. I will need to scan all modules but the fan control module are integrated in ECM which I don't know whether if it fail I would be able to fix it by individual model or not. Will see after the MSV-2 activated and scan the DTC. Will keep update.
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| 24th Sep 2009 7:44 am |
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DG
Site Moderator
Member Since: 12 Dec 2005
Location: The Gaff
Posts: 50936
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Good luck  21 year LR veteran > D2 GS 2003 > D3 S 2006 > D3 HSE 2009 > D4 HSE 2013 > D4 HSE 2015 > D5 HSE 2018 > DS HSE R-Dynamic P300e 2021
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| 24th Sep 2009 7:46 am |
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sitticheep
Member Since: 10 Sep 2009
Location: Thailand
Posts: 11
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Hi, the scan result doesn't look problematic. after a fault cleared. The symptom still there with no further fault code. So, I decided to use trial and error method to change parts but unfortunetly those part can not be found in local dealer. Any one could point me where I can get(Over online order) the pressure transducer the Microcat P/N is JTE000010 A/C shop here who experienced fixing clutchless A/C with modern car confrim that this sensor is the most suspected one.
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| 25th Sep 2009 7:45 am |
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DG
Site Moderator
Member Since: 12 Dec 2005
Location: The Gaff
Posts: 50936
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Send a message to Nick "The Large One"
http://www.disco3.co.uk/forum/member2459.html
He can ship parts around the world 21 year LR veteran > D2 GS 2003 > D3 S 2006 > D3 HSE 2009 > D4 HSE 2013 > D4 HSE 2015 > D5 HSE 2018 > DS HSE R-Dynamic P300e 2021
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| 25th Sep 2009 8:12 am |
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10forcash
Member Since: 09 Jun 2005
Location: Ubique
Posts: 16534
 
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You need to read dynamic data from the fan speed sensor, it's not common but the sensor can give a false high reading, causing the PWM signal to reduce the duty cycle. If the fan speed indicated does not vary with engine speed or seems abnormally high at idle, then you need to change PGG500370 for the TDV6, PGG500360 for the V8 or PGG500350 for the V6.
Note that this particular condition does not generate a DTC as the signal is considered valid
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| 25th Sep 2009 1:53 pm |
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sitticheep
Member Since: 10 Sep 2009
Location: Thailand
Posts: 11
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Hi thank you for help. But I don't have computer reading orther than MSV-2 So, I guess I wouldn't be able to read it right?
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| 25th Sep 2009 2:06 pm |
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10forcash
Member Since: 09 Jun 2005
Location: Ubique
Posts: 16534
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Dunno, I use Autologic, maybe there's an independent near you with Autologic?
The LR dealers can also read the dynamic data with IDS
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| 25th Sep 2009 2:23 pm |
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sitticheep
Member Since: 10 Sep 2009
Location: Thailand
Posts: 11
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10forcash wrote:Dunno, I use Autologic, maybe there's an independent near you with Autologic?
The LR dealers can also read the dynamic data with IDS
I just mess up my car when I use MSV-2 to do car configuration data retrive and write but it might cause from using by IE8 the whole thing gone bad. all the module are now unable to talk to each other. may I ask 10forcash or who ever who does experience with IDS and autologic whether those tools will be able to recode all the module back to standard working with original VIN again or not?
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| 25th Sep 2009 6:09 pm |
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BBS SPY
Site Sponsor
Member Since: 15 Jun 2007
Location: Sunny Cyprus
Posts: 3054
 
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Hiya Sitticheep
As TFC says, because the MSV-2 does not currently provide any Live data monitoring, you would need to find an indie or dealer with AutoLogic or IDS to see that value. I am sorry about this, the MSV-2 is a powerful tool capable of many amazing things but it is very much a work in progress with a lot of things still being added.
However i understand that you have changed your vehicles CCF settings and now have other problems. My technical support staff also tell me from your posts on our tech support forum, which you joined only today having only just got your MSV-2, that you elected not to save the settings as recommended in the systems help etc, before making changes and writing them to the car, meaning you now cannot program the car back to how it was before you started experimenting with it's settings. 
There are scratch pad copies of the CCF in the EMS and Body control and although we provide the ability to sync these with the master copy in the Instrument pack it is a one way thing. Well in fairnes we imagined providing the function to save the master on your hgard drive was enough.
What you therefore now need to do is go to someone who has an IDS who will be able to restore your CCF data using their systems built in AS Built files. If you cannot do that then send me your VIN number and we will turn the IDS "As built" file into a data set that your MSV-2 can use. But that won't be quick or easy as its not something we are typically set up to do.
BTW a scan is designed only to show what ECU's are fitted to a vehicle to aid us in licencing single Vehcile systems other than a Disco 3, which requires always but one licence, it is in no way a diagnostic aid as stated in the systems help.
I hope this helps Chap
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| 25th Sep 2009 7:08 pm |
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matt_tdv6
Member Since: 05 Feb 2009
Location: Lincolnshire
Posts: 937
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I have the viscous coupling without a fan
I changed mine as the fan was damaged but isnt available seperate so i ended up with a spare coupling
PM me for more details
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| 25th Sep 2009 7:39 pm |
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