Radiator Fan turn on even when cold

[clarksongli]

So recently i got the P480 code.  Fan was running non stop on high.  When i turned the car off it kept running on high so i pulled the fuse and went to bed.  In the morning i threw in the fuse and the fan didn't run.....turned the car on (Cold) and after a few seconds went to high again.  Turned off the car and it ran on high for a while then shut off.

 

So i had to do a bunch of work anyways so i pulled the fan assembly, here are the steps i've done so far:

 

AC fan works fine, this is only the main fan.

 

If i power the fan without connecting to the car (the small wires arent receiving signal) the fan stays off (which i think is good).

If i measure the car harness side, it shows the standard 12v and 0v on the plug.  The signal wires show ~.3V and 12V

 

My guess was the 12v was the cause of the fan running.

 

To rule out the temp sensor i unplugged it, but the 12v signal was still there.  plugged the fan in anyways and it was still running.  I did notice when it was unplugged the car only shows as "normal" temp, it didn't peg to the top like i'd think it would.

 

Finally i found that F10 is the signal (Fan Final Stage)

 

Anyone have the wiring diagram or know where this 12v is coming from?  I'm 99% positive it does NOT come from the main coolant sensor.  And i'm also 99% my fan is working correctly, but i don't have the "before" voltage check to know for sure.

 

Any help would be appreciated.

 

THanks 

[JFP in PA]

You may have a bad relay on that fan; suggest pulling it while the fan is running, if it switches off, you found your problem.

[clarksongli]

does the fan have a relay? i'm pretty sure it doesn't.  straight power from f10

[Loren]

AC on? or cold defrost on?

Those would also likely cause the fans to run.

[JFP in PA]

does the fan have a relay? i'm pretty sure it doesn't.  straight power from f10

 

Item #12:

 

 

Retails for just under $20.

[bigbuzuki]

The attached wiring diagram shows the fan power coming from the 60 amp fuse F1 and the 30 amp fuse F10.

Edited November 22, 2015 by bigbuzuki

[clarksongli]

does the fan have a relay? i'm pretty sure it doesn't. straight power from f10

Item #12:

Retails for just under $20.

Jeff are you sure that's not the starter relay? What's the pn on it?

[JFP in PA]

 

 

does the fan have a relay? i'm pretty sure it doesn't. straight power from f10

Item #12:

Retails for just under $20.

Jeff are you sure that's not the starter relay? What's the pn on it?

 

 

# 141-951-253-B  $18.79 One of three (#8):

 

 

You may want to check that part number with a dealer, it has been superceeded more than once.

[clarksongli]

 

 

 

does the fan have a relay? i'm pretty sure it doesn't. straight power from f10

Item #12:

Retails for just under $20.

Jeff are you sure that's not the starter relay? What's the pn on it?

 

 

# 141-951-253-B  $18.79 One of three (#8):

 

 

You may want to check that part number with a dealer, it has been superceeded more than once.

 

Where is this located?  the Water Box?  I have some relays in there but none of them are listed as anything to do with the fan???

 

Thanks for the help btw.

[Ahsai]

Per the wiring diagram buzuki posted, it does look like the fans don't use relays but rather have solid state circuits within them and are controlled directly by the fan control module.

 

From this document, it sounds like your problem http://cardiagnostics.be/-now/Hella-repairsolutions/Porsche,%20Cayenne,%204,5%20l%20V8%20mit%20Motorcode%20M48.pdf

 

Google translated here if you don't read German (I don't).

 

"Transferability: This case depends on the installed cooling fans. This affects only Vehicles with two fans (dual fan module). This can also at Cayenne models Specialty engines (and diesel) occur.

 

Problem: The vehicle will not start anymore because of a deep-discharged battery. The driver reported unusually frequent and long run of the radiator fan.

 

Fault memory: It is the fault code 16864 / P0480 saved, equivalent to 'Radiator fan control 1, electrical fault '.

 

Tip of the Technical Call Centers: These cases are piling up. In some cases, off both radiator fan even in a parked vehicle. Then run until the capacity the battery is exhausted. The reason for the continuous operation are manufacturing-related dust inclusions in the control unit of the cooling fan 2 (smaller fans), the well Radiator fan 1 controls.

 

Troubleshooting: According to the manufacturer the complete dual fan module needs to be replaced"

[JFP in PA]

 

Per the wiring diagram buzuki posted, it does look like the fans don't use relays but rather have solid state circuits within them and are controlled directly by the fan control module.

 

From this document, it sounds like your problem http://cardiagnostics.be/-now/Hella-repairsolutions/Porsche,%20Cayenne,%204,5%20l%20V8%20mit%20Motorcode%20M48.pdf

 

Google translated here if you don't read German (I don't).

 

"Transferability: This case depends on the installed cooling fans. This affects only Vehicles with two fans (dual fan module). This can also at Cayenne models Specialty engines (and diesel) occur.

 

Problem: The vehicle will not start anymore because of a deep-discharged battery. The driver reported unusually frequent and long run of the radiator fan.

 

Fault memory: It is the fault code 16864 / P0480 saved, equivalent to 'Radiator fan control 1, electrical fault '.

 

Tip of the Technical Call Centers: These cases are piling up. In some cases, off both radiator fan even in a parked vehicle. Then run until the capacity the battery is exhausted. The reason for the continuous operation are manufacturing-related dust inclusions in the control unit of the cooling fan 2 (smaller fans), the well Radiator fan 1 controls.

 

Troubleshooting: According to the manufacturer the complete dual fan module needs to be replaced"

 

 

I always thought that device was a relay, just called by another name, as Porsche uses relays on their other earlier vehicles.  After reading up on this device, apparently this new control unit eliminates the need for resistors to control fan speeds (which were always troublesome), and is also being used in the later cars as well.  Learn something new every day.  Thanks Ahsai.

 

On the downside, instead of a $20 relay and a couple of resistors, now you need to jump for a $700+ fan assembly.

[Scott C]

The

87 and later 928s used fan speed controllers.  It is a pulse-width-modulated power transistor controlling voltage to the motors to change speeds.  If the part is $20, than that is cheap compared to the 928 units.

[Ahsai]

Actually your posts and buzuki's made me search so I also learned something new :)

 

This is very similar to the dreaded BMW electrical water pump. The mechanical motor parts are fine but the electronics within is toasted. It's not clear from the German article how to test the fans though. I would think one can use Durametric to activate the fan(s) manually.

 

 

 

 

Per the wiring diagram buzuki posted, it does look like the fans don't use relays but rather have solid state circuits within them and are controlled directly by the fan control module.

 

From this document, it sounds like your problem http://cardiagnostics.be/-now/Hella-repairsolutions/Porsche,%20Cayenne,%204,5%20l%20V8%20mit%20Motorcode%20M48.pdf

 

Google translated here if you don't read German (I don't).

 

"Transferability: This case depends on the installed cooling fans. This affects only Vehicles with two fans (dual fan module). This can also at Cayenne models Specialty engines (and diesel) occur.

 

Problem: The vehicle will not start anymore because of a deep-discharged battery. The driver reported unusually frequent and long run of the radiator fan.

 

Fault memory: It is the fault code 16864 / P0480 saved, equivalent to 'Radiator fan control 1, electrical fault '.

 

Tip of the Technical Call Centers: These cases are piling up. In some cases, off both radiator fan even in a parked vehicle. Then run until the capacity the battery is exhausted. The reason for the continuous operation are manufacturing-related dust inclusions in the control unit of the cooling fan 2 (smaller fans), the well Radiator fan 1 controls.

 

Troubleshooting: According to the manufacturer the complete dual fan module needs to be replaced"

 

 

I always thought that device was a relay, just called by another name, as Porsche uses relays on their other earlier vehicles.  After reading up on this device, apparently this new control unit eliminates the need for resistors to control fan speeds (which were always troublesome), and is also being used in the later cars as well.  Learn something new every day.  Thanks Ahsai.

 

On the downside, instead of a $20 relay and a couple of resistors, now you need to jump for a $700+ fan assembly.

 

 

 

No, John means a simple relay is $20. The electronic modules of these fans are built-in and are not meant to be serviced/replaced so if they break, the whole fan will need to be replaced.

 

The

87 and later 928s used fan speed controllers.  It is a pulse-width-modulated power transistor controlling voltage to the motors to change speeds.  If the part is $20, than that is cheap compared to the 928 units.

 

 

[Ahsai]

Clark, does your fan(s) look like this?

 

[clarksongli]

Clark, does your fan(s) look like this?

 

 

That is the A/C fan, I'm talking about the large passenger side fan.  It also has a "box" attached to it.

 

Here is my original question, I've already taken the fan out of the car and plugged in 12v with no "signal" wire....the doesn't run....which tells me that the signal wire is commanding the fan to come on.

IMO this rules out the fan and module attached to it.  But maybe I'm wrong?

 

In my ORIGINL post, the 2 signal wires show 12v and ~.3V......I think it's the 12v that's triggering the fan to come on.

[JFP in PA]

 

Clark, does your fan(s) look like this?

 

 

That is the A/C fan, I'm talking about the large passenger side fan.  It also has a "box" attached to it.

 

Here is my original question, I've already taken the fan out of the car and plugged in 12v with no "signal" wire....the doesn't run....which tells me that the signal wire is commanding the fan to come on.

IMO this rules out the fan and module attached to it.  But maybe I'm wrong?

 

In my ORIGINL post, the 2 signal wires show 12v and ~.3V......I think it's the 12v that's triggering the fan to come on.

 

 

Ahsai is correct in his assumption that either the Durametric system or the OEM PIWIS should be able to trigger the fan to run.  I think yours should look something like this:

 

[clarksongli]

 

 

Clark, does your fan(s) look like this?

 

 

That is the A/C fan, I'm talking about the large passenger side fan.  It also has a "box" attached to it.

 

Here is my original question, I've already taken the fan out of the car and plugged in 12v with no "signal" wire....the doesn't run....which tells me that the signal wire is commanding the fan to come on.

IMO this rules out the fan and module attached to it.  But maybe I'm wrong?

 

In my ORIGINL post, the 2 signal wires show 12v and ~.3V......I think it's the 12v that's triggering the fan to come on.

 

 

Ahsai is correct in his assumption that either the Durametric system or the OEM PIWIS should be able to trigger the fan to run.  I think yours should look something like this:

 

 

 

Jeff,  no offense, but triggering a fan to run, which is already running, isn't going to tell me anything.  If I already know the trigger wire is hot when it shouldn't be, I need to figure out why that trigger wire is hot.

 

Hence why I asked the question, where is this motor control unit.  It is NOT the one on the fan housing.  If you look at the wiring diagram, the module has only three wires, and it is connected between both fans.....if you look on the fan housing, and in your picture, they clearly are never connected until you trace back into the car side of the harness.

[JFP in PA]

 

 

 

Clark, does your fan(s) look like this?

 

 

That is the A/C fan, I'm talking about the large passenger side fan.  It also has a "box" attached to it.

 

Here is my original question, I've already taken the fan out of the car and plugged in 12v with no "signal" wire....the doesn't run....which tells me that the signal wire is commanding the fan to come on.

IMO this rules out the fan and module attached to it.  But maybe I'm wrong?

 

In my ORIGINL post, the 2 signal wires show 12v and ~.3V......I think it's the 12v that's triggering the fan to come on.

 

 

Ahsai is correct in his assumption that either the Durametric system or the OEM PIWIS should be able to trigger the fan to run.  I think yours should look something like this:

 

 

 

Jeff,  no offense, but triggering a fan to run, which is already running, isn't going to tell me anything.  If I already know the trigger wire is hot when it shouldn't be, I need to figure out why that trigger wire is hot.

 

Hence why I asked the question, where is this motor control unit.  It is NOT the one on the fan housing.  If you look at the wiring diagram, the module has only three wires, and it is connected between both fans.....if you look on the fan housing, and in your picture, they clearly are never connected until you trace back into the car side of the harness.

 

 

OK, let's look at the basics:  There are a limited number of things which can tell the DME to make the fan run, and at what speed; the coolant temperature sensor (which you have already eliminated) and the AC system during cooling or cold defrost.  I would take a look at the AC system controls; if the AC system is not calling for the fans to run, the DME has a problem and is causing the false triggering.  On your model, the Durametric can also scan the AC system as well as activating the fans, so that might be worth a look as well.

[clarksongli]

With the ac on the small driver side fan runs.....with the ac off the small driver side fan turns off.

The large fan, from my understanding, does not operate with the ac system....only the engine coolant temperature.

My question still remains the same. What should I be reading with the meter on those two signal wires? Is 12v and .3v appropriate for full speed?

Talking about the relays again I see there is something called the hcs relay in that diagram....what does hcs stand for?

[Ahsai]

Understood your logic since one of them can be at faul: the DME, the 3-wire fan control, or the fan itself. Without knowing exactly how the fan is controlled by what signal, you can't conclude if the fan is bad. I think unless someone measured it before on a known unit or there's documentation, that exact info is probably difficult to find. Besides, who knows how complicated the signal is, it could be a simple voltage level or it could be PWM...

 

My thinking was with Durametric, you can park the car, stop the engine, hook up your car on a good (>10A) battery charger and let the fan run and wait for it to stop (if it ever stops). Then maybe you can connect durametric to command the fan on/off. If the fan complies, it means the fan and the fan control module are good. Of course this is assuming the fan eventual stops and it doesn't turn itself back on once you turn the ignition to connect Durametric.

[Ahsai]

Another point I forgot to make. It seems the P0480 code is flagged if the the DME commands the fan to turn on/off but it detects that the fan is not behaving correctly (probably by detecting the actual current drawn).

[Ahsai]

Hence why I asked the question, where is this motor control unit. It is NOT the one on the fan housing. If you look at the wiring diagram, the module has only three wires, and it is connected between both fans.....if you look on the fan housing, and in your picture, they clearly are never connected until you trace back into the car side of the harness.

I checked more Cayenne wiring diagrams. The "motor control unt" is actually the DME. Motor = engine in this case. So to answer your question, those three wires connect directly to the DME. So basically the DME drives the two fans directly.

See post #5 here for DME pinout and note pins A48, A66 and B104.

http://rennlist.com/forums/porsche-cayenne-forum/552741-does-anyone-know-the-ecu-connector-pinout-for-2005-cayenne-s.html#post7348316

Edited November 24, 2015 by Ahsai

[clarksongli]

So here is my conclusion, based on half measurements and half hoping:

 

The fan module is bad.  If i pin on the measurements on the small fan, i get the exact measurements (whether it commands on or off) suggesting it is a PWM signal of some sort.  Now that i can "assume" the signal is correct to the main right fan, that only leaves the fan itself.

 

Here is a question, does anyone know if the fan is the same as the one on the touareg?  The PN doesn't cross reference, but the part itself looks insanely similar.

 

Here is a link to a picture:

http://www.ebay.com/itm/2004-2010-VW-Touareg-Radiator-Fan-Motor-1639642-/321925620544?fits=Model%3ATouareg&hash=item4af4432340:g:TtgAAOSw6dNWTm8b&vxp=mtr

[deilenberger]

Just to toss in some related experience. Friend owns a shop - does some Cayenne work for a few of us - he also happens to be an electrical-engineer and ham radio nut, so he's well known in the area as the guy to see for weird electrical problems.

 

Had a Cayenne (think an '04) come in with the eternal-running-fan problem (main engine fan as described above..) He tracked out the input trigger signal to the control box (which is mounted to the motor assembly) and disconnected the signals - the fan kept on running.

 

The problem was the fan controller - which is not a seperately available part - so the owner of the P!G was out the cost of an entire new fan assembly.  New fan assembly worked flawlessly.

[clarksongli]

Just to toss in some related experience. Friend owns a shop - does some Cayenne work for a few of us - he also happens to be an electrical-engineer and ham radio nut, so he's well known in the area as the guy to see for weird electrical problems.

 

Had a Cayenne (think an '04) come in with the eternal-running-fan problem (main engine fan as described above..) He tracked out the input trigger signal to the control box (which is mounted to the motor assembly) and disconnected the signals - the fan kept on running.

 

The problem was the fan controller - which is not a seperately available part - so the owner of the P!G was out the cost of an entire new fan assembly.  New fan assembly worked flawlessly.

Yeah.  I took a leap of faith and ordered a fan.  I've checked as much as I could and from what I can tell, the car/harness side of the whole thing is working correctly.  I'll know tonight when I get home from work.