Hello all, I've had a look through the posts. The only post that I could find that was relevant says it isn't relevant to the 130bhp, so I'll have to ask. A few seconds after starting the car, the cooling fan on the radiator ramps up to full power, very noisy. It doesn't matter if aircon is on or off, or if the engine is hot or cold. Some posts on the web suggest that if the coolant temp sensor isn't working right, then this could be a problem, but I don't believe it is malfunctioning. I've got VCDS-lite and connected it up. For the engine it says:-
Thursday, 29 March 2018, 12:39:34.

VCDS-Lite Version: Release 1.2

Control Module Part Number: 038 906 019 NB

  Component and/or Version: 1,9l R4 EDC G000SG  6249

           Software Coding: 00002

            Work Shop Code: WSC 00020

                      VCID: 64BB2F93E743

1 Fault Found:

18062 -  Please check DTC Memory of Instrument Cluster

        P1654 - 35-10 -   - - Intermittent

------------------------------------------------
For the instrument cluster it says:-
Thursday, 29 March 2018, 12:40:58.

VCDS-Lite Version: Release 1.2

Control Module Part Number: 7M5 920 920 S

  Component and/or Version: KOMBIINSTRUMENT VDO V61

           Software Coding: 13401

            Work Shop Code: WSC 00001

                      VCID: 42F7C90B5D97

1 Fault Found:

00779 -  Outside Air Temp Sensor (G17)

        30-00 -  Open or Short to Plus

Neither fault will clear. The outside temp display in the dash says -.-- and has done for ages. This cooling fan thing has been going on for ages too...

Is it the fault with the outstide temp sensor that is causing this problem?

I can see two right next to each other clipped into the front bumper on the nearside. One is like a little metal cap, maybe 18mm diameter, the other is more plastic with a three pronged clip that holds it in the hole. Which on of these is the outside temp sensor? Can the wiring/voltages be tested? would you expect 12V on one of the terminals or is it some sort of comms connection. Can the sensor be replaced by a resistor just to fool it temporarily for elimination purposes? The bumper has been ripped off by a motorbike in the past, just wondering if the wiring is damaged.

Otherwise the car goes great, 140000 miles

Sorry about the long post. I have studied the posts about the aux heater and will change that heater plug, as that shows a fault too. Also the post about the parking sensors excellent, ordered a new sensor from well known auction site.

Thats usually a wiring fault between your instrument cluster and the temperature sensor.

But also, Iââ,¬â,,¢m sure the first fault listed from the coolant temperature sensor, so it may be worth checking itââ,¬â,,¢s still in working order or trying one from someone else.

Thanks KingyMAK. Will a fault on the outside air temp sensor cause this issue with the cooling fan running at full speed?
Are there two signals from the coolant temperature sensor in the engine? I saw coolant temperature referenced 3 different ways in the measurement blocks but all the readings were the same. There is also a sensor in the outlet from the radiator.
Any thoughts about two sensors behind the front bumper and whether they would have a 12V supply?

I'd try unplugging the switch in the radiator hose and see if the fan stops as your first step. It looks like this is the one your talking about > https://www.ebay.co.uk/itm/Temperature-Switch-Radiator-Fan-for-VW-Audi-Seat-Skoda-1H0959481C-7215818-/311463964545 Microcat describes that as "switch assy - Fan Motor" so that should be whats switching it on. Disconnecting it I would expect to stop the fan. If it does then replace it, though its possible its a wiring problem at the same time.

The air temp one shouldn't make any difference to the fan speed, they don't usually though there looks like there is a problem with yours anyway. Again that may be wiring rather than the actual sensor.

Thanks Brian, i think your diagnosis is more for the engines under 130bhp with two cooling fans? The sensor ob the bottom hose is only 2 wire.

The attached shows what i looked that part number up from - I've specified 130 so it should be right?

Number 7 is the selected part there. So it should be right? At any rate unplugging the switch should tell you something as they are usually open until the temp closes them, at least that should give you some idea anyway.

Hi Brian, the picture of the single fan etc looks ok, but there is no sensor with the orientation as in the picture. The intercooler is hard against the front of the radiator allowing no room for anything. The sensor I have is in the bottom hose, has two pins, and when i disconnect it I got the fault code 17698 - Coolant Temp Sensor at Radiator Outlet (G83): Signal too Small (My shareware vcds-lite did not give me this explanation of the code, it was google).
I'd like to see measuring blocks above 25 but it does not seem possible with vcds-lite. Is there any other way of looking at the values from the sensors?

Don't know with what you've got, but would suspect if you can't find it then its not possible without the full version. Since you can get to the connector on that sensor, I'd suggest it might be an idea to unplug it and check the resistance of it with a multimeter, both with it cold and hot. If its reading something odd then you might get an idea if its the cause. At least posting what it reads back here should give a good indication to anyone else to aid you. If it seems the same in both hot and cold then its probably failed anyway? I've tended to find they either break completely (and give nothing) or go a bit randomly bad (shooting between hot/cold in a few seconds).

It may also be an idea to unplug that sensor and see if the fan stops running if you haven't already?

I will try and look at the sensor resistance tomorrow. the fan still runs with it unplugged.

Meanwhile, the outside temperature sensor is still defunct

Finally got a chance for a proper look at this today. Front bumper off. One of the wires easily pulled out of the connector to the outside temp sensor. When I pulled the sensor from the connector i could see that the inside was damp. I had ordered a new sensor from well known auction site. The old one was open circuit. New one about 1.9kohm at 10 degrees. Dried everything with hair dryer. Bodged the wire back into the connector and sealed it all up with silicone gasket. Temperature display now reading correct and the bloody fan has stopped, so that's a result. The thread on a dodge site was right, if the ecu doesn't know the outside temp it ramps the fan to 100% as a failsafe. In case you're in the Sahara.
But the engine doesn't get warm enough. I need to check if the thermostat is stuck open.

The diesel engines don't run particularly hot anyway - Theres a large volume of coolant in the galaxy, Does your run on pump and booster heater work?

Good to hear you've found your problem anyway, at least it seems relatively easy to fix once you know.

Thanks Brian, I know the diesel heater isn't working, that's on my list. Not sure about the pump. Should that start running as soon as ignition is on?

Yes it should do. Its a dumb pump so if its worn the brushes out it just won't work, no faults logged.

Your heater might not be working as its overheated due to the non-working pump. Once certain codes get logged 3 times on them it will lock out, you then need to use VCDS to reset it.

If the brushes have worn on the pump they can be replaced, eBay being cheapest place to source them if your not in too much of a rush (a search on here should give you the required sizes)

Just wanted to wrap this up by saying i changed the thermostat and renewed the brushes in the run on pump. Needle now gets to 90 and stays there. I suspect that is more due to the thermostat than the pump. The auxiliary heater still not working, that's another project.

the aux heater wont start by itself because the temp is too high now,mine ran from 11 degrees.think there is a way to make it run?might be done by bridging the temp sensor??
others will point you in the right direction.

Yes you can bridge the wiring at temp sensor to bring aux heater in.
I ran wires from temp sensor to dash mounted toggle switch so I can control when it comes in etc

Hi was the ambient sensor the culprit or coolant temp sensor? I have the exact same problem on Passat b6 1.9 tdi. The ambient sensor in my dash doesn't work at all. Thanks

The Passat might work differently but the galaxy/sharan ambient temp reading and aux heater use different ways to give ambient temp and heater switch on.

Ambient temp reading uses a sensor,aux heater uses a temp switch that closes below 10 degrees.