s80 Won't Turn Over
 

I have a recently purchased 2000 S80 T6 that now doesn't want to start. It was working fine until a few days ago when suddenly it wouldn't turn over at all. The electrics all work when the key is in positions I and II, but all I get when turning to position III is a soft relay sound behind the dash. There's no starter soleniod sound from the engine compartment at all. Every once it a while the thing works and the car starts and runs fine. The key lock had been acting funny, and I thought it might be the electrical switch on the ignition. I changed that out but it didn't make any difference. After a while the car started once with the new switch in place, but that doesn't seem to be the problem. Is there some other relay or soleniod that I should be looking for? I don't have a wiring diagram for the vehicle yet, so I was hoping someone might have experienced this and could point me in the right direction. Thanks for your time.

Is there a message in the window when it will not start?

No, there's no indication in the message window, and all the other warning lamps are illuminated as normal during startup.

OK then what I would try is using a test light on the small wire on the starter when the key is turned. If the light lights up the starter is bad.
If it doesn't light up then it is something in the car.

Whack the starter with a hammer.

I'll give the test lamp a try tomorrow and see what happens. If the lamp lights up I'll look at the starter. Thanks for your help.

Well, I put a Fluke on the starter solenoid wire and did not get any voltage/current when activating the ignition switch, so it's not the starter. I'm going to try again to download the manual as described in one of the other posts (S80 Diagnostic Software). I'm having a little trouble getting the utorrent software to work (something about reassigning ports), but I'll see what I can find. Let me know if anyone has any other suggestions. Thanks

I would think immoblizer but that will usually throw the message on the window.

There definitely aren't any messages in the display, but I should have some wiring diagrams by the morning (that's quite a download) and hopefully then I can start to diagnose the system. I'm not as familiar with the newer cars and I'm assuming that the complexity is fairly significant, but I've managed to troubleshoot and keep a 97 Range Rover going, and those cars are a nightmare.

I'm still working on getting a wiring diagram, but I did try a couple of other things. The current state is that it generally will not start or do anything when the key is turned. I checked the battery, which was fine. I then discunnected the battery for about 20 minutes and hooked it back up with no improvement, although now I get the SRS message in the window. Then I saw on a couple of other posts that folks had wiggled the main cable to the starter soleniod with some luck. I tried this and the engine started just fine about 3 or 4 times. The it stopped working again. I wiggled the cable a bit more (there's a very little bit of play, but not because the cable is loose but rather the solenoid post is turning very slightly) and it worked again, and then stopped. I tried again without having any luck anymore. I'm a little confused because this would indicate a problem with the starter/solenoid, but when I checked the activation wire to the solenoid it didn't register any voltage when the key was turned. I'm really at a loss here as this doesn't seem to follow any logic. Anny suggestions that anyone might have? Thanks for your help..

Do you have another key for the car that you can try?

I was out of town for the weekend so I didn't have time to work on the car. I do have 2 different keys that I've tried, and the behavior is the same. I just now went out and tried again. The car started right up, so I turned it off and tried again, and it also started. I shut it off and hooked a meter up to the starter wire (the small wire) and tried again and no voltage was seen when the key was turned. I hooked the wire back up to the soleniod and tried again and no luck (tried about 20 times with both keys), so it appears to be intermittent. I downloaded the Vadis software to find some wiring diagrams for the relays. etc., but have not been able to get the software to work (looked everywhere in the files downloaded and can't find a password to use). I was thinking that I could check the voltage at a starter relay if I could identify it, and that maybe that would give me an idea of where the problem was. I'll keep working on it and provide more details. Thanks for your all your help.

So I decide to tap off of the starter wire to see if I could read anything in the cases where the car did start up (more to verify my method than anything else), and I found out that the problem does appear to be a lack of signal to the starter solenoid. The car will start about once every 30 tries, and I don't see any signal to the solenoid. In the few cases that it does start, then obvioulsy there was a signal to the soleniod that I could read, so my method is OK. It did this with 2 different keys, so it doesn't appear to be related to that issue. I also definitely don't get any messages in the window, so I'm hoping that it's a bad/sticky relay somewhere. I'll keep looking....

It has to be a relay or something like that.

That was what I was thinking. I've managed to downlaod Vadis and get it working on my desktop to look for information, but for the life of me I can't find any wiring diagrams in this system to even show me which relay(s) are associated with the starter. I did read the starting system configuration info in Vadis and did see that there is a relay that the ECM/CEM modules direct to activate, so I know it's one of the relays in the main engine compartment box, I just have to figure out which one. I was thinking if I could identify it, there are some duplicate relays that I might switch out (as long as I knew which ones they were so as to not disable some ciritcal subsystem) to see if I could narrow the problem down. Again, thanks for your input as it does provide reassurance.....

There should be a sticker under the fuse panel cover under the hood. That should tell you which one it is.

The sticker only identifies the fuses, not the relays.

OK I will see if I can find anything tomorrow.

Thank you very much. I may or may not get the Vadis SW figured out by then, but I'll let you know.

Tech,

Well, now I'm really at a loss. I previously checked the starter activation wire, and there was no signal when the key was turned to the start position, so I concluded that the starter was OK and not the problem. I checked the starter fuse, which was good, and then finally located the starter relay, which I was hoping would be the problem. The relay wasn't being activated, so I took it out and activated it with a 12VDC signal on the workbench, and it seems to be fine. This leads me to believe that the relay is not being energized by the CEM. If the immobilizer is functioning and I have a problem with the key it should set a message (as you had pointed out earlier), but this isn't the case. I've tried starting in Park and Neutral, as I know there's a neutral safety switch, and this doesnt seem to make any difference, so it seems to point to the CEM, unless I'm missing something. I've been trying to avoid having the car towed to the dealer (an expensive proposition due to the distance), but I'm out of ideas now. Any suggestions before I bite the bullet and take it in? Thanks for your help.