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Discussion Starter · #1 ·
My alarm system on my 2004 Murci has lost its mind. Here's the story:
  • Car has been driven pretty much every weekend for exercise with nothing usual
  • Battery is a couple of years old
  • Keep it on the Lamborghini branded CTEK tender to stay charged
  • Voltage with the kill switch disconnected: 12.7V
  • Voltage with the kill switch connected: 12.6V
  • Voltage with ignition on but no accessories: 12.3V
  • Voltage with lights and AC blower fan on 12V
  • Voltages are holding, so battery appears good.
  • Using my normal start sequence of the last 5 years (get in, key to accessory, press unlock, start car), the car won't start. I just get relay clicks in the cabin.
  • Cannot unlock or lock the doors with any of my 3 keys fobs.
  • If I remove the battery kill switch and plug it back in, the hazards flash for exactly 25 times, and the alarm is set. This repeats every time without any variance.
  • Cannot disarm with the key fob, so if I open the door after the flashing of the hazards, the siren goes off, and I need to disconnect the battery to get it to stop.
Anyone seen this behavior before? I can't see anywhere what 25 flashes of the hazards signifies, but I am sure it's the med alarm trying to tell me what's wrong with it.
 

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Hello Stimpy.

I have spent a fair bit of time studying this alarm system in case it ever fails on my car. I also helped a friend with his alarm issues on his 2004. I know the starter relay is located behind the drivers seat. If you hear it clicking I suspect you have a starter or a relay issue. (You can try swapping starter relay with one of the rad fan relays i believe they are the same) By studying the electrical prints I have, I can see that all the MED unit is doing is cutting the 12 volt positive feed to that relay. (on the relay coil supply) (It also cuts the fuel supply when armed but right now we are dealing with the no crank issue) Therefore ,if you hear it clicking the MED system is not currently cutting your crank signal. I cant speak to why the doors wont unlock etc. That could be the MED unit itself or possibly a fuse. There is a fuse inside the MED unit itself. It would be interesting to measure if there is 12vdc on the small wire on the starter while you are hearing the clicking during a crank attempt. Hope this helps a little.
 

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Discussion Starter · #3 ·
Thanks, 03! That gives me some things to check.

I'll need to get a voltmeter on the starter to see what's going on there. And I'll try swapping out the relays.

Do you know where the med module is located? I been through most of the car in past projects, but I can't remember seeing it. I'd definitely like to check that fuse in that unit.
 

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Hi Stimpy.

Its on the passenger side to the right of the radio. You just need to remove that small side panel beside the radio on the passenger side. I can also tell you that the two wires that are colored blue with red stripes (Going into the MED plug) are the normally closed contacts while alarm unit is happy. If alarm is unhappy they open and that is what cuts the 12 volt coil supply voltage to the Starter relay. We confirmed this on my friends car by temporarily jumping these wires, However his situation was a but different. He could not lock or unlock his car. But there was no click while trying to cycle the key from the relay. There is also another fuse related to this alarm and if I'm not mistaken its on the drivers side under the small panel on the side of the dash. Its the one with the symbol of a car window going down. so double check all those fuses too!
 

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Discussion Starter · #5 ·
Thanks!

I had heard from a friend on here that there are fuel valves controlled by the alarm system, and looking at the shop manual just now, that appears to be the case:

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Hi Stimpy,

Yes that is correct. That is the only other way the MED unit prevents starting on the first Gen models. The MED valves are located behind the carbon fiber engine bay panel on the right side. They are attached to the fuel filters and are controlled by 3 wires each. So luckily its quite basic and not Tied into the CAN LINE system. After you find your alarm module up under the dash you can also unplug that annoying siren from it until you get things sorted. I can look up wire colors / pinout for the MED valves on my other computer tomorrow if you need that information. Good luck! If this ever fails on my car I have a good mind to just bypass it as I hate this alarm..
 

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Discussion Starter · #7 ·
Thanks again!

I found the MED 2000 unit just inside that panel. The unit is just sitting on top of the airbag module, not even tied down in any way. The fuse tested just fine with the meter, so that's not it. All the pins on the large connector looked just fine.

No change in behavior after removing and reinstalling the med unit. I'll definitely leave off the siren for now. I have to put on ear protectors during testing it's so piercingly loud.

I'll check other fuses and relays in the morning. I am definitely worried at this point that the module has failed, and I not sure what it takes to get it repaired or replaced. I've heard horror stories though.
 

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Hi Stimpy,

Yes I have heard those horror stories too that's why I really wanted to get an understanding of this system so if mine fails I can hopefully bypass it. One thing I forgot about is that the Red LED in the back between the seats also acts as an antenna. ( I actually learned that from this forum) Maybe try moving one of your Key FOBS closer to this LED as another test. Others have had some success for a while with this method. I looked at the wiring schematic again this morning and can tell you that the Green wire on pin 10 of the MED unit is the control signal going to the MED solenoids. The black wire at the MED solenoid is ground. The Brown wire is 12 volts with key on.

Here is what I do not know and would love to hear from others in order to better understand this system......

Are the MED solenoids closed all the time and only open if alarm is happy? Or are the MED solenoids always mechanically Opened and closed if the alarm is Unhappy? The reason this matters is if solenoids are always opened, then in theory they can just be unplugged! I have heard they can just be unplugged but it is not confirmed. (Mechanically removing them and bypassing is another option)

Secondly what exactly is the green wire doing at the MED solenoids. Most solenoids are only 2 wire. These are 3. The research I have done suggest that the third wire may just be a pulse signal to open/close the solenoid.

Lastly are these solenoids possibly paired to the MED alarm brain? I cant really see how they could be following the wiring but I could be mistaken. Perhaps this is another function of the green wire?

Our cars are getting older and this information is getting harder to find out. Unless places have very senior Lamborghini Technicians it has been my experience that even dealers don't fully understand this old system! Sure they know the new cars very well but a lot of Technicians who worked on these cars back in the days may have retired. So the more we discuss this system the better for all of us to learn and repair or bypass it!
 

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Discussion Starter · #9 ·
I checked the 2 alarm-related fuses behind the passenger kick panel, and they are fine.

Moving the key next to the module or the LED didn't work.

So what I have read recently is that the alarm module is talking to the ECU, so if that's the case, it's not going to be easy to bypass that alarm because it's more likely than not sending a more complicated signal to the ECU than just 12V on or off.

The fuel solenoids can be physically bypassed with units from the Diablo, or I am sure you can get the right fittings from a plumbing store to make your own bypass. You could just leave the solenoids connected to the wiring if they need to be there for the alarm module to work. The solenoids are paired somehow to the alarm module and have to be replaced with it, if your don't have the 6 digit PIN for the alarm module (most owners don't at this point), and they are the expensive parts of an alarm system replacement.

The fact that my alarm isn't responding to any of my key fobs, and that it flashes the hazards 25 times, and then auto-arms the system (never did that before) every time I power up means to me that there's a good chance I have a bad module.

I would like to get Med to confirm what 25 flashes means because it's not in the manuals, and it's not mentioned in any forum posts. It must be an indicator of my particular error condition. It seems possible the flashes might mean one of the solenoids failed to communicate with the alarm module. Who knows. I really need to know before trying to repair anything.

If the module has failed, I first like to try a shop that repairs modules. Here's one that Alex found, but they have zero contact info on their website, and say they don't work retail. I can get around the retail thing with a little help from some friends, but no idea how to contact this business. Their website address was registered in Dec 2019, so they are probably still in business:

 

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Hi Stimpy,

Did you check the 12 fuses on the left side of the dash on Drivers side? Specifically fuse 11 labelled ECU. Sorry I may have misled you before when I said it was the one that looked like a window going down. My friends car had a blown fuse on fuse 11 when it would not crank at all.

I have also looked at every PIN on that MED connector and followed it through. I really could not see anything relating to CAN on these older cars. Newer Murcies may be different. However I am no expert. That is why it would be great to hear for others that may know this 100 percent.
 

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Discussion Starter · #11 ·
I'll check those fuses next. I already have that panel open.

It looks like Med is out of business. They let their website expired in 2017, and no current sign of them anywhere on Internet. If that's true, that's not good for all of us with Med systems.
 

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You probably saw my other posts where mine ended up being the starter itself. Maybe also check your dome light right upon opening the door, as I was told sometimes the car still thinks the car is locked after you open the door and therefore will not start. Your situation is more unique than mine, but if you get under the car to do anything maybe try to start it with a remote starter hooked to the starter rather than with the key and see what happens.
 

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Discussion Starter · #14 ·
You probably saw my other posts where mine ended up being the starter itself. Maybe also check your dome light right upon opening the door, as I was told sometimes the car still thinks the car is locked after you open the door and therefore will not start. Your situation is more unique than mine, but if you get under the car to do anything maybe try to start it with a remote starter hooked to the starter rather than with the key and see what happens.
I do remember your post well. Funny you mentioned the dome light. I was noticing how it turns on when you open the door, but shuts off in less than 10 seconds. Alex tried his 07 LP640 and his dome light behaves the same way.

I plan to raise the car up later today and check voltages at the starter. I definitely hear clicking and whirring noises when trying to start it.

The really odd part is how the alarm flashes the hazards 25 times every time I power up the car, or open the doors. The siren won't go off with the 25 flashes during the initial powering up, but the siren will go off with the hazards when the door is opened. It just didn't do that before, so even if the starter is bad, something else is going on.
 

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Yeah pretty funkarama with that alarm business. Just FYI my dome light goes off too soon after opening the door so it sounds like your car is properly detecting the door is open with the light going on when opening and then off. I know you mention that it won't unlock the doors with the fob and I suppose you then use the key, but does it chirp on or off when using the fob? You hate to ask but like in Christmas Vacation, "is it plugged in Sparky"? In other words with the fobs you have are you sure the batteries are good? Maybe the 25 flashes is just the normal alarm going on and then turning itself off at 25? I never had mine go off so I don't know what normal is. Currently on mine sometimes the doors don't unlock but that's probably the door actuator; however the key fob always chimes the alarm system on or off.
 

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Discussion Starter · #16 · (Edited)
Had a little bit of a breakthrough today.

I checked that there definitely wasn't 12V getting to the starter motor, which was expected given the alarm issues.

I took out the Med 2000 box again, and drilled out the 4 holes to open it up. There's no screws, it's plastic welded shut, but very easy to drill out the welded points.

The board looks pretty good and it's mostly coated front and back with silicon, which helps keep away corrosion and makes the circuit boards more vibration proof. Did see a little bit of buildup in a couple of spots as shown in the pics with the white deposits, so I brushed those areas off. Otherwise, I didn't see anything that looked off.

Plugged the unit back in, and powered up the car, and it was doing the exact same 25 flashes. The relays in the Med 2000 handle the flashing of the hazards on their own, instead of sending a signal to some other flasher relay. I could feel and hear the clicking from the Med unit. I left it exposed without its box, and I thought I wasn't making any progress, but then I tried the key fob, and it locked the doors! I was then able to unlock the doors and start the car! Yea, but I didn't really do anything to fix it, so I didn't expect it stay fixed. Sure enough, a couple hours later and it was back to the exact same broken behavior with a no start condition.

But it's great that it did start at one point, and I think it's safe to say it's isolated to the Med box. I dropped the unit off at PoKnow's house because he has a knack with re-soldering the circuit boards to fix any dry joints.Hopefully his work will solve the problem. Otherwise, I am going to need to go through the process of replacing the Med box, which will be painful.

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Stimpy,

That is some great troubleshooting you have done! I hope that by having your friend go over those solder joints that your problem is resoled. Please keep us posted! I am going to go over all of those pin outs on the MED unit and post the function of each wire when I get some more free time. I still believe that this alarm is not tied into CAN system on 2002-2004 cars. If that is the case then when mine fails I may just bypass the Starter kill and fuel shut offs. As far as being able to lock and unlock the car I can just use a key. The car never leaves my sight anyways. I don't leave it unattended and never really lock the doors.
 

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Discussion Starter · #19 · (Edited)
Stimpy,

That is some great troubleshooting you have done! I hope that by having your friend go over those solder joints that your problem is resoled. Please keep us posted! I am going to go over all of those pin outs on the MED unit and post the function of each wire when I get some more free time. I still believe that this alarm is not tied into CAN system on 2002-2004 cars. If that is the case then when mine fails I may just bypass the Starter kill and fuel shut offs. As far as being able to lock and unlock the car I can just use a key. The car never leaves my sight anyways. I don't leave it unattended and never really lock the doors.
Thanks!

If you do that work, you can easily wire in another $50 unit for managing the door locking and unlocking functions, but you'll probably have to add a different key fob to your keychain, which isn't a big deal, and is normal for this era.
 

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Discussion Starter · #20 · (Edited)
if yours can't be repaired, looks like Lambo part# 410937101 for a new MED unit
Getting a new Med unit seems to be easy enough. The question is what's involved in the swap?

Do I need a special computer or other equipment to program it to the car?

I don't mind removing the fuel shut off solenoids, but will the new Med unit operate if those solenoids are missing or if the old ones are left wired up but not sync'd with the new unit? I don't have the PIN of the old Med unit to program the new Med unit to the old solenoids, so I would need to replace the otherwise working solenoids and they are stupid expensive $1000 each, and you need 2 fresh, never programmed units. PN 410937305
 
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