Odd radiator fan behaviour (6C GTi 1.8TSi)

[Bepis]

After a decent motorway run, I noticed my fans had kicked on when I pulled into a services. It was decently warm today so I assumed it's just cooling down as the oil temp was up to 107C so the coolant was also probably just as warm.

However, after 10 minutes the fans were still going and had even gone up to what I think was stage 2 of 3 in their speed. Concerned I opened the bonnet and there was a fair bit of heat but the air coming off the radiator wasn't too hot.

I thought maybe one of the coolant sensors was reading high with the engine being off and no coolant circulating so I started the engine briefly to get the cold coolant moving through. Start the car, fans go off, then come straight back on. Turn the car off again, fans go off, then they come back on again.

I waited for half an hour with the engine off and bonnet open, the whole time the fans going quite hard. The coolant temp gauge drops and the oil is now reading 62C and they're still going as fast as they were at 107C oil temp. With no warning lights or evidence of something wrong other than the fans, I drove home.

I pulled up to my house and the fans were off but the second I switched the ignition off they were now going even faster than before which I assume would be their 3rd stage. But the coolant temp was reading 90C and an oil temp of 102C.

I plugged in my VCDS expecting a list of fault codes the length of my arm but nothing... Nothing whatsoever. I tried cleaning fault codes in the ECU, no change. Then ran an auto scan and cleared all fault codes, no change. I shut everything and locked it to see if it'll change when the modules went into their sleep mode. No change, fans still going all out.

After probably 40 minutes they turn off, then on slowly for 30 seconds, then off, then on again, and straight back off. Then I heard a relay click in the engine bay and nothing since.

I've disconnected the battery so the fans don't randomly kick on at full speed and let it sit overnight and have everything discharge.

Any ideas? My first thought was the fan switch or relay but the fact there are no fault codes has me baffled.

Also can I open the boot from the inside or do I need to manouvere myself through the back seats to reconnect the battery

[Bepis]

After some digging, I found this post viewtopic.php?t=70813 and this from RossTech http://wiki.ross-tech.com/wiki/index.ph ... 480/001152

I also found a prior auto-scan from a month ago where I had a code for an intermittent malfunction with coolant fan control circuit one P0480 00, nothing odd was happening at the time but it might be an issue now.

I gather it should either be on the passenger side frame rail under the air box, or on the fan shroud itself. I have manual Climatic AC and the fault code was under the ECU so I think it'll be on the fan shroud.

5J0919506 seems to be the J293 module, £30~ on ebay used or £150-£200 from the dealer. Can I use any J293 module that has a matching part number or will it need to be from a car with the same engine?

Is there also anything else which triggers the fans to come on other than coolant temperature, or the air con being switched on?

Am I correct in assuming that the J293 module is what directly controls the fans which is also the relay and that it receives the relevant signals from the ECU to switch on and at what speed?

[Bepis]

Set out this morning to find the fan control module and I'm fairly certain it's on the radiator fan shroud. However, it's on the other side and sandwiched between the shroud and the radiator.

Fan control module.jpg (2.46 MiB) Viewed 5706 times

I inspected the plug on the bottom left of the fan shroud and wiring I couldn't see any corrosion or breaks

ECU side fan plug.jpg (2.19 MiB) Viewed 5706 times

Fan pack side plug.jpg (1.95 MiB) Viewed 5706 times

I connected the battery back up with the fan plug disconnected to see what faults would be logged and got the following:
1 Fault Found:
15048 - Coolant Fan Control Circuit 1
P0480 00 [039] - Electrical Malfunction
Not Confirmed - Tested Since Memory Clear

Which was the same code I got a month ago but without the odd behaviour I'm getting now.

Started the car and let it sit for a bit and the fans stayed off and no fault codes. Fans switched on with the aircon and switched off when the aircon was off.

I took it for a fairly long drive to get everything hot, sat in some traffic the fans turned on and turned off as they normally would. However, I noticed that when I was sat and the oil temp reached 107C the fans came on and seemed like they were going quite hard so I watched the oil temp drop to 98C and they were still going. So the problem is still present.

When I got home I plugged in VCDS to read some live data and check faults. The same fault that was triggered when I left the harness unplugged was back and the coolant temp was at 106C with the engine running. I turned up the fan for the interior and set it to hot and watched the temp fall to 90C with no change in fan behaviour.

Turn the engine off, the fans continue to run, however on starting the engine the fans turn off for around 20 seconds. I tried turning the engine off during this period and the fans still came back on and kept going until the coolant temp reached 60C in the block and 22C at the radiator.

The only strange thing I could see in live data was that the "Coolant temperature at radiator output specified" was at -48C.

After locking the car the fans did ramp up and back down 3 times over 20 minutes or so and then nothing else.

I believe the run of wire to the module or the module itself is faulty as the same fault code comes back immediately upon clearing faults like it's unplugged.

[Bepis]

Some more observations:
When the car is unlocked the fans will power cycle twice
When the ignition is turned on, the fans will start immediately and run for some time once the ignition is switched off.
Once the fans turn off they will again power cycle twice.

[RUM4MO]

I'm sure that this has been covered already within the VAG motoring forums, but sorry I can't provide the usual root source, can you work out if the electric cooling pump is operating okay as it might have failed or another component in the engine cooling system might have failed and this behaviour is the "last stand" to protect the engine.

Cooling fan control module, have you tried to check the operation of the fan(s) and variable speeds, by applying a link to the temperature sensor thing on the radiator - if these cars still have that?

[Bepis]

I can hear the electronic pump turn on and off when I turn the cabin fan on and off with the temp set to hot so I believe all is well there.

As far as I'm aware there's one mechanical water pump and one electronic water pump on the 1.8 TSi with the electronic water pump feeding the heater matrix inside the car and then the turbo after the engine is shut off. But I'm not 100% sure.

I'm going to look for the fan module again as I don't think it's on the fan shroud but one of the chassis legs instead as I don't think the module (5J0919506) could even fit where I think it is. On top of that pictures of the reverse of these fan shrouds shows nowhere for a module to go, only connectors for fans.

Fan shroud backside.jpeg (245.44 KiB) Viewed 5659 times

5J0919506.jpg (241.77 KiB) Viewed 5659 times

[ciclo]

It looks like the radiator fan control unit on the 1.8 is built into the fan itself.



e.g https://es.aliexpress.com/item/32940817416.html

[Bepis]

Yeah, it seems to be that the module is contained within the primary fan and is starting to fail as I can command it on and off via an output test using VCDS. Fuses 1 (50A) and 18 (10A) in the engine bay have continuity. Fuse 37 in the passenger compartment was also listed as supplying module J293 and it is also fine. So I'm pretty sure power supply isn't an issue.

The behaviour seems to be either the fan gets commanded on then something goes wrong in the module where it doesn't see the off signal from the ECU so keep going until Terminal 15 power is cut when the ECU goes to sleep. Or something goes wrong in the fan control module meaning the ECU can no longer see it so as a failsafe it just signals the fan to come on. I'm just guessing as I can't see any other reason why it would do what it's doing.

However, with the fault code set, I can still output test the fan so the ECU doesn't seem to block the module, and the aircon still works fine. The fans also don't power cycle when I unlock the car or come on as soon as I switch the ignition on.

Edit: Brose is an automotive parts supplier but it seems they don't sell aftermarket. However, FCP Euro in the states say that Mahle is the OEM for part number 1K0959455FR (MAHLE ORIGINAL CFF 187 001S) which is significantly cheaper than OE. https://www.autodoc.co.uk/mahle-original/15289747

Questions:
Given I can command the fan on and off via the ECU would I still need to check the signal wire from the ECU?
There's a connection point in some conduit ontop of the passenger/nearside frame leg that then leads down to the man fan connector. Would that be B352? As at the fan pack plug, I have a yellow wire with a black trace but no red wire with a black trace just the purple and black trace for ECU signal.

Radiator fan plug.jpg (1.16 MiB) Viewed 5456 times

[ciclo]

B352 is just a connection point (splice) inside the wiring (not visible) between the red and black wire and the yellow and black wire because your 6C has the battery in the luggage compartment (just that).
It is a positive power signal (87) usually dedicated to electrical parts of the engine (valves-solenoids, sensors, etc.)

The communication wire (black/violet wire) between J623 and J293 seems to work correctly due to the output tests you have done...

Since it is not yet a diagnosed fault, I would start to check and clean the electrical connectors of the engine cooling system.











1.8l petrol engine, DAJA, DAJB (PDF) https://drive.google.com/file/d/1RvA-aE ... sp=sharing

I do not have the images of the parts to install or remove for this engine, I hope you find where they are located. (googling?)

[Bepis]

I guess the process of diagnosis will be to check wiring/plugs, then when the fans have been switched on, unplug one of the temperature sensors and see if the fans stay on or turn off?

From what I've been able to find and see on the engine it self, the G62 coolant temp is on the gearbox side of the head of the engine.
G83 will obviously be somewhere in the radiator outlet hose or on the outlet itself.
G226 will be in the sump
The rest of the coolant shut-offs and valves I'm also fairly certain are somewhere above the gearbox amongst all the coolant hoses and connections. Will just need to find the corresponding wire colours and follow them.

I'm still only getting the one fault:
15048 - Coolant Fan Control Circuit 1
P0480 00 [039] - Electrical Malfunction
Not Confirmed - Tested Since Memory Clear

Which only appears once the car is hot and will immediately come back when cleared while the car is still warm. If I clear it after the car has sat overnight it won't come back and the odd behaviour comes back.

Is it possible that the module internally shorts or a connection breaks when it's hot? As the output test was done when the car was cold with the fault stored.

[ciclo]

Yes. I think you are forced to test with a new J293 radiator fan control unit.

[Bepis]

Yeah seems so. I've ordered a new Mahle primary fan from Autodoc which usually takes a week to get to the UK.

I guess the final check I could do is to remove the pin for the purple and black ECU control wire from the plug on the fan pack and plug it back in like in this video: https://www.youtube.com/watch?v=Isiy-i8hABQ

The last hurdle for this is actually getting the radiator fan pack out. Every other VAG fan pack seems to be held in with 4 T30s and the mk7 golf has a clip style. However, my fan pack has 4 pegs that seem to push down and into seats that are molded into the radiator end tanks. The tops of them are exposed so it might just come up and out if you can get a tool in there.

I'll try and get a good picture but there isn't much space to get a phone into.

[ciclo]

Good test in the video, diagrams always help...

I think that in some PDF I have the installing and removing process of those radiator fan packs for 6R/6C model, but right now my laptop's SSD hard drive won't boot -checking media fail- and I can't access the info. The BIOS does not recognize the boot device with the OS (W10).
I am in the process of repair, none of the tricks or tutorials on the net work...

Let's see how it goes when you install that new J293.
If you consider it convenient, take some images of the process, this thread is worth it.

[Bepis]

I'll see what I can get as there clearly isn't anything available online yet

Regarding the storage issues, if you have access to another pc you can take the SSD out and connect it to another pc using a USB to SATA cable and copy the data you want to save over. Then if its an option stick the SSD back in and do a fresh install of Windows via a USB ISO. However, a drive not being detected even in BIOS isn't typically a good sign

[ciclo]

I tried, but nothing at all. The reading device is detected, but only that. I'm afraid this SSD 1TB has died.

Is there any way to repair it? Special programs, etc... or physically? Clone it to a new SSD?

With this 1TB SSD in the BIOS boot menu, the windows boot manager does not appear. I tried Legacy mode, but it doesn't work for me.

This previous image is with the original 250GB SSD, which is the one I currently have installed, everything works great.