Willow5

Is it possible to take an OEM satnav radio from a 2009 cayenne (PCM 3) and put it into a 2005 Cayenne to replace the BE6635? Is it compatible in terms of physical size and wiring?

Thanks @GSpence2 I agree heat is not the right way to go. I am just surprised no one else has ever encountered this problem before. I also don't think brute force will work either as that is how I broke off the delicate tabs.  I saw one video on youtube which involved brute force hitting the tab with a hammer which I will not be doing. Any other suggestions?

Thanks @GSpence2 although this guide mentions the three pipes, I couldn't find the part where it mentions separating the 3 pipes from the thermostat housing or did I miss something?

Hi there,

I can't believe no one doesn’t know how to safely separate these pipes as I have already damaged the delicate tabs on one set and now bought a replacement so don't want to damage another set. Is there a tool for this as right now I am totally defeated

Hi,

My 2005 4.5l Cayenne last had replacement Aluminium coolant pipes done in 2010.  Since then, it has covered 100k so clearly need to renew the O rings.  Question: does anyone know how to separate the 3 pipes into the upper thermostat housing ? They seem to be well and truly stuck in there. I tried heating it a bit and only managed to move it a little bit out but I am concerned with the fragile Aluminium that I could damage them if I continue with brute force. 

Doesn't anyone here know the function of the door tailgate switch??

I came across this article on another forum which describes exactly what I am encountering. Please can someone kindly confirm this is the operation of the tailgate switch and keyfob?

Hi there. Before I go and get the scan done and spend more time troubleshooting, please can someone kindly confirm the operation of the tailgate switch in the drivers door.

I read on a touareg forum that the function of the switch is as follows:

"On mine (an '04) that switch only allows you to open the hatch after you have locked the car. ie, flip the switch, get out of the car and lock it, go to the rear and open the hatch using the switch above the license plate, retrieve your packages, close the hatch and the car re lockets itself. The feature times out after about a minute. In other words, the switch allows the hatch to open for a period of time after the car is locked. It does not open the hatch directly."

Is this the correct function of the switch when working? If so, I have been operating it incorrectly.....

@JFP in PA, I understand thanks. Are there any other troubleshooting guides online that I could take a look at ? My troubleshooting logic is this:

There is clearly a connection between the drivers door control unit and the rear part of the car given that I can open the fuel cap. The control unit clearly has access to the CAN bus in order for this part to function. The tailgate itself and all the motors are fine given that I can open all rear doors fine with the buttons on the rear. The tailgate switch is also working fine.

My only other thought was that there could be a broken wire somewhere....I read a few times that wires occassionally get torn between the door rubber boot and the body.  I have yet to take the rubber boot off to inspect further. Could this be an issue?

@JFP in PA, ok then are there any further troubleshooting techniques I could do in absence of a PIWIS or reader? I read the voltage at the tailgate switch pins in the drivers door card and they check out ok but I have 4 wires and the diagrams I have seen only show 2...slightly confused by this

Hi @JFP in PA, if I were to simply replace the driver door control unit, could this be done without any reprogramming,  for example, is it a simple plug and play swap ? I could source one quite easily from ebay.......are these prone to going bad?

Hi @JFP in PA and @Loren, to be honest I am not sure I will get hold of such a scanning device anytime soon given the lockdown.

In absence of this, can I get an idea of what sorts of issues could cause the faults I am observing. Could this be a driver door control unit issue for example?

Hi @Loren, forgive me but what type of things could such a scan pick up? I am of the opinion (rightly or wrongly) that this is a hardware issue like a broken wire or ground issue, what do you think?

Hi @Loren, no not as yet. I assumed this was a simple wiring/grounding issue given the following conditions are true:

1) the rear tailgate switch appears to be working fine

2) the fuel cap release switch from the drivers door is working fine which is also routed into the drivers control unit

3) there is voltage on the pins foing into the tailgate release switch

4) the switch itself is ok

Right now, I have 3 unresolved issues:

1) starter motor is sluggish and never starts on first turn. Always takes at least 2 turns to fire up

2) rear tailgate release button on the drivers door and remote keyfob are not working (although with a long keypress on the keyfob, the rear tailgate glass panel does release).

3) the alarm doesn't sound, only the hazard lights illuminate

Would a PIWIS or Durametric scan assist with these issues?

Please note that I managed to clear up 1 issue with some cleaning of the ground points which was the original issue I had with the central locking not locking the tailgate, this now appears to work correctly.

Thank you @Rick150. Is there a diagram similar to the one I posted above that shows the "tailgate switch" and the "tank cover unlocking switch" which routes into the "driver door control unit". I am only interested in this now as those controls are on the drivers door and that is where the problem is

Hi @Rick150, no need to check the fuse as the tailgate opens and closes perfectly when I use the handle at the rear.

Please can you kindly send me all the wiring diagrams for the interior lights circuits as that is where the switch for the tailgate release is located.

I have this diagram but it makes no sense to me as both the fuel flap and tailgate lid switches are connected to the same wires. Can you explain it at all as I am baffled by it. 

Also I have 4 wires going into my tailgate switch, not 2. The other 2 are VIO/WHI and Brown which are not shown here....this is a complete mystery to me

Hi @Rick150, hope you are keeping well during these times.

Can you please dig out thr wiring diagram for the interior tailgate release button as I think I am getting close to resolving this issue but need to identify where this button routes. In the past you send me some diagrams but nothing with the interior tailgate release button so far.

Just out of interest, I read somewhere that this button is disabled if the cayenne thinks it has a towbar fitted. Question is how do I disable a towbar if the cayenne thinks it is installed? Can't see anything visually near the rear bumper but I am no expert on the settings yet. Thank you

Thank you @Rick150. What else is connected to MB23 please?

Hi @Rick150 and @JFP in PA. Please can one of you kindly point out where MB23 is located? I see from the diagrams that it is the left side of the dash but what I don't quite know is whether it is buried under the footwell carpet or whether it is actually somewhere to the left of the centre console? 

The reason I think it is important to trace is because it is linked indirectly to the rear comfort systems module via the signal horn and this is one connection I haven't addressed.

On another note, I tried cleaning the joints under the wiper arm cowls but this has not has the desired effect. I have yet to test a volt drop over the cables so that will be my next option.

Finally, please can you kindly advise where the rear comfort systems module is physically located? 

Thank you both. 

@Rick150, I will be cleaning them tomorrow because I simply couldn't get in the small opening with my drill attachment. Do you have any images that show what connects to GP11, 12, 13 and 14 in terms of wiring diagrams?

@JFP in PA, good idea. Which wires should I test? There are an awful lot of them. Also do you know where the negative ground strap to the starter motor is physically routed inside the engine bay so I can feel for any heat?

Thanks both, this is a lengthy process but hopefully will pay off soon

Sorry for the additional clarification but do you mean the connections near the battery (i.e. under the seat area) or under the bonnet please ? slightly confused :S

Will try to clear the warnings but have no diagnostic reader, will try to get hold of one and see what happens.....

Anyway, today I cleaned up MB42, MB43, MB20 and MB21. Nothing appeared to change from before so then I decided to pop the hood and looked at GP11, GP12 and GP14 and I must say that they looked visually awful with white surface corrosion to the terminals as they are directly under the windshield wiper cowl (not really sensible from a design point of view). I have yet to clear these terminals up and try again but in the meantime, please can you kindly let me know what is connected to these points?

Also, I tried looking for MB1 and MB5 but couldn't locate them at all - even after removing the headlight. Any ideas where I should be looking for these points? I think I have found a smoking gun 🙂

Hi @Rick150, the CCA of the starter battery is 900A and the battery itself is brand new so I can eliminate any battery related issues. Unfortunately I don't have a diagnostic unit that can read the voltage curve when starting.

Where are the terminals you mentioned related to starting? Happy to put my hand on them but not sure if they are under the bonnet or near the battery fuses.

I forgot to say that I also have a 3rd fault which is:

3) Air Suspension Faulty Workshop error message appearing on the screen when I switch the car on

Is there any way of testing this ?

Today I will re-do the ground points in the roof (MB42 and MB43) and any others I can locate. Will report back later.

Thank you for all your help

Hi @Rick150. Well it seems that the original problem I had with the central locking has been resolved by re-doing various earth points around the car and in the boot. The strange thing though is that there is no audible warning when the alarm goes off and the motion detector detects movement inside the car (I tried this by having the window down then putting my arm inside once the car was alarmed). The only warning is the hazard lights flashing. 

That aside, I am left with 2 main problems:

1) starter motor is very slow to start the car, always starts on 2nd attempt not on 1st

2) I still cannot open the tailgate from the keyfob or the driver door button (but I can open the tailgate glass if I keep my finger pressed on the keyfob tailgate button for more than 2 seconds)

Do you know where the central locking module is located? Perhaps there is a fault with this unit?

Can you please let me know the exact locations of MB20, MB21, MB22, MB23, MB30 and MB31 please?

Other than this idea, I am now running out of options other than the engine bay area and the ground straps there....

Any other ideas?

Thanks @Rick150. For information, here is the broken stud

Thanks @Rick150. I feared this was the case...there appears to be a plastic cover under the chassis directly under the bolt. Do you know how to remove this cover at all?

Just a couple of extra questions if I may:

1) Do any sensitive electronic equipment need to be removed prior to welding (e g. ECU)?

2) What type of welding would suit this joint: MIG or ARC? (Bearing in mind I need someone to come to me instead of driving the car to a garage)

3) Can I just buy a normal M6 nut and weld it as a captive nut from under the vehicle or do I need to buy a special nut? Does the manual say what length the nut is?

4) Which wires terminate into this junction? Could it relate to my problem?

Hi @Rick150, sorry for the delay, I have been troubleshooting this over the past few weeks. So tonight, I think one of the grounding points could have possibly been the reason for this problem.  The ground point in question from your diagram is MB26 (under the UK side drivers seat). It was barely hand tight and has 2 pairs of heavy duty brown wires going into this junction. When I tried tightening it up, unfortunately the bolt snapped which means I now have a problem. Do you know how I can remove this bolt and renew it? It looks like it is bolted down but a standard 12mm socket seems too large while an 11mm socket is too small. Are these ground points welded down or bolted down?