Bigdave1230

It’s not a hard job but it is fiddly. I’d recommend doing it on a ramp as you need to take the wheel off and the engine under tray to get access. It’s only held in with one allen key bolt. The sensor was about £60 I think. Mines a 3.0 v6 but I think the 4.2 v8 has 2 and might be in a different place so would be worth checking beforehand if yours is a V8.

Eurocarparts actually sell replacement bare engines (no alternator, turbo etc) but you have to ask them as they don’t list them on their website. But the main problem is finding somewhere willing to take it out as it’s a massive job! The only one I’ve ever seen taken out was by Audi who have a special table that locates into holes in the subframe and enables the whole drivetrain to come out as one unit ( engine, gearbox and subframe still attached) which lowers out from underneath.

Metal not meter

Have you tested the voltage with a multi meter on the jump points under the bonnet on the passenger side? I’d measure there then get the negative jump lead and connect to the negative terminal and clamp the other side to somewhere meter on the engine. Then measure it again and see if there’s a difference. Test it with the engine off and then with it turned on. Even 1 volt is a big difference. Should turn over quicker with the jump lead connected.

My mates Q7 just had a funny problem where the battery would go flat over night maybe once every couple of weeks. Battery tests fine and couldn’t fathom out why it was doing it. Turns out it was the auxiliary heater fan that was kicking in by itself during the night ( the auxiliary heater wasn’t turning on it was just some sort of fan associated with it) only reason it was found was one morning when he went out to it he could hear the fan before he opened the car. Pulled the 20A heater fuse on the passenger side of the dash board and it’s been fine since. Auxiliary heaters seem to be a bit rubbish on these anyway. If you run the car low on fuel and they try to kick in they lock up and need vcds to unlock them so most Q7’s aren’t working.

Could also be the starter but that’s a 4 hour nightmare of a job. If it’s not turning over at all I’d be more inclined to think starter thinking about it

Crank shaft sensor. Car will start and drive fine then when it starts to get warm and you park up the temp under the bonnet continues to rise as there’s no air flow. The faulty sensor gives an implausible signal when hot so when you try to start the car again the engine doesn’t get the correct position data so will either turn over and over or turn over for about 2 seconds then stop cranking just like it would if it had started correctly. Can be really intermittent and won’t show any fault codes in vcds. Leave it to cool down and it will fire up fine. Happened on mine last year

Air releasing after you get out and lock up is normal it’s just the car levelling itself. I have a Bosch Agm start stop battery on mine which isn’t coded in because it doesn’t have that model in its coding and it’s fine. Coding is only so the car knows at what point to turn everything off in the car if your sat in it with the ignition on and not running so it still has enough power to start the car.

What is the cars actual fault symptoms?

Should be fine. Has it fixed your problem?

Yeah your right I just didn’t want to go too far into it. I thought that was the simplest way to answer that’s all.

Does the fan gradually slow down until it stops or just cut out like flicking a switch?

All negatives on the car are linked. The negative terminal on the battery goes to the body of the car. The negative from the starter goes to the body that’s why they are called earths/earth straps. The problem isn’t the positive as that’s a dedicated wire that indirectly goes straight to the positive terminal on the battery. The negatives/earths at the bottom of the engine are open to the elements and corrode against the body and as such mean that the system can’t make a good circuit. By putting an extra earth/negative at the top of the engine the you are improving the circuit. You could just get a jump lead and connect from the terminal in the picture to anywhere on the engine to see if it cures your fault.

😳 it’s negative don’t try it from the positive! You can go to any bolt on the engine as long as it’s not into anything plastic. I’m not sure what gauge cable it is as the auto electrition supplied it but you should be able to get one from any car spares shop.

The units are coded to the car to try to make them useless if stolen. 🤔 I think the head unit and the mmi screen are a pair so might be why you aren’t getting sound but I think the mmi usually says “no cd” rather then plays no sound though. I had a problem with my mmi screen not long after I bought mine and the garage said they had replaced the screen and the cd changer. So if you can try the 09 mmi screen with the 09 cd changer it might cure it but I’d be tempted to run a scan on vcds before paying anymore money out. I dare say the scan will probably say it’s in “component protection” mode. Which as far as I’m aware only audi can remove with VAS software linking back to Germany. Audi probably won’t want to help you code a 2nd hand unit and try telling you only new units can be coded.

If I was looking for a mk1 Q7 I’d get a 2011 onwards as this was the year where the 6 speed gearbox was changed to an 8 speed unit which makes the car cruise a lot better and drops the tax bracket so it’s no longer nearly £600 a year. Also the mmi will be a 3G unit with sd card storage rather than the 2G unit which had a 6 cd unit built into the dash but no sd card storage. There are 2 versions of the 2G unit (2006-2009) a high and a low. All cars which have sat nav are high versions which has a colour screen. The low unit has a red screen which doesn’t look very attractive. Easy way to tell if a car has sat nav if looking at pictures before visiting a dealer is to look at the rear roof section as sat nav cars have a shark fin at the back. The 3G unit can be manipulated in vcds to copy cds onto the jukebox storage and also play dvds whilst in motion. Cream of the crop is a 2014-2015 sport edition which has the V12 body kit, 21 inch alloys and almost every option available. Expect to pay around £22k for a good low miles example with a pan roof.

Hi does anybody know if the newer generation Q7 3.0 engine with 218bhp Is “exactly” the same engine as the 3.0 272bhp engine but just with a different Ecu map? Looking at changing my current 2008 Q7 to a newer one and have been looking at the 272bhp as I think the 218bhp one will be a bit gutless. But would get a high spec one and for a few hundred quid remap it. Both 218 and 272 engines remap to 320bhp which makes me think it’s the same engine but don’t want to get a “weaker” engine and push it out of its comfort zone if it’s not. cheers Dave

A common place for the aircon to get a leak is behind the plastic inner wheel arch on the passenger side. The is a pipe that runs through there and up into the engine bay where the fuel filter is. It’s held onto the body with a metal clip with a rubber bush. The rubber deteriorates and ends up metal on metal until it rubs through. Just replaced mine for that reason.

Level sensor. You should be able to turn the steering wheel to see them without having to get under the car.

Check the level sensor on the upper front arm on both sides. If it’s come loose and fallen out the car will think it is higher than it actually is so will lower the front to try and level itself

Bagpippinandy do compressor repair kits for about £25ish. Normally the compressor gets very noisy when the piston ring is worn. I’d measure the centre of the wheel to the wheel arch on all 4 wheels to see if there is an obvious difference on one wheel then check the sensor etc on that wheel. A leaking air bag would make the car sink overnight. Does the car try to level itself Slightly if you park it on a slope then get out and lock it?

I’d check/replace the fuel filter for signs of anything nasty in there that could be restricting fuel flow but it sounds like a fuel pressure/pump issue. My mate had a problem with a regulator that created a low fuel pressure fault code but I think his symptoms were a little different to what your experiencing. Unfortunately he’s moved to Australia so I can’t just ask him. If you have vcds you should be able to do some checks in the adaptation. I’ll email him and see if he replies. Good luck

Might sound stupid but does the rear washer jet work and are the rear number plate lights work? The rear washer jet connects onto the rear wiper motor and is prone to leaking into the boot panel where it corrodes the terminals for the number plate lights and boot release. Tell tale sign is one number plate light out and the rear washer jet not spraying onto the window but hearing the washer motor. The boot can start playing up too as in you press the button to open it and it either does nothing or opens an inch then immediately try’s closing again. Hope you get sorted