ENGINE WON'T TURN OFF

[tonycharente]

I'm in the middle of redoing the sticky buttons on my late 2005 4200 CC, and had reached the point where I wanted to test them in the car as some of them didn't seem to want to push properly. I therefore plugged in the accessories panel (the one with the window switches) and the aircon panel. I had disconnected neither the radio panel nor the reverse gear selecter module. Prior to attacking the buttons I had disconnected the battery with the cut-off switch. I therefore switched that back on, and then turned on the ignition. Only the window switches worked. I then started the engine in order to test the aircon buttons. When I then tried to turn off the engine, it refused to turn off - even with the key removed. I tried the spare key - no better. Turning the battery cut-off switch didn't stop the engine - the alternator saw to that... In a panic I disconnected all the fuel injection leads to stop the engine, which worked. I later found that I could simply pull the little 20 amp fuse powering the fuel pump, which was a lot easier.
With the fuel pump fuse back in place I initially could start the car at will, but the engine would still not stop without pulling the little 20 amp fuse powering the fuel pump,
Then things got worse...
I next got the "Maserati code" warning light come up (a symble of a car with a padlock through its windscreen). I looked this up in my handbook, which implied the need to go through a hyper-complicated procedure involving a 5 digit code to be able to start the car, to be repeated each time you want to start the car...
At this point I used my Launch X431 to read the codes, which included "P1570 Immobilizer". I cleared that code, the"Maserati code" warning light turned off and I was able to start the car no problem. But still not switch the engine off.
I realise that the problem could be down to a faulty ignition switch, but it's the very first time I've ever had this problem and I find it hard to believe that it could just happen to have failed whilst I was working on the sticky buttons - hence my giving all the background.
Any ideas please? All ideas welcome.
Tony

PS I have disconnected accessories panel (the one with the window switches) and the aircon panel, and then started the engine again. No change, the engine still won't turn off.

 

[DLax69]

First guess is you may have shorted something to ground...

 

[tonycharente]

First guess is you may have shorted something to ground...

Thank you very much DLax69, but I don't see what or how I could have shorted anything to ground. I had the battery cut-off switch turned off before I started and also whilst I was connecting things up. But if I did shorted something to ground, how would that have damaged the ignition switch?

 

[DLax69]

Thank you very much DLax69, but I don't see what or how I could have shorted anything to ground. I had the battery cut-off switch turned off before I started and also whilst I was connecting things up. But if I did shorted something to ground, how would that have damaged the ignition switch?

If something is applying continuous voltage, it reads that the ignition is still on...doesn't actually have to be the switch itself, just something that effectively closes that loop.

 

[tonycharente]

If something is applying continuous voltage, it reads that the ignition is still on...doesn't actually have to be the switch itself, just something that effectively closes that loop.

Thanks again DLax69. I have disconnected accessories panel (the one with the window switches) and the aircon panel, and then started the engine again. No change, the engine still won't turn off.

 

[DLax69]

Thanks again DLax69. I have disconnected accessories panel (the one with the window switches) and the aircon panel, and then started the engine again. No change, the engine still won't turn off.

Weird. It's just too coincidental (to my mind) that you were in there and the ignition switch just happened to go out...

https://www.scuderiacarparts.com/part-finder/maserati/4200/oe/59/3549/62337

 

[tonycharente]

Weird. It's just too coincidental (to my mind) that you were in there and the ignition switch just happened to go out...

https://www.scuderiacarparts.com/part-finder/maserati/4200/oe/59/3549/62337

Yes I totally agree - it's almost certainly something I've done - but what?

 

[CatmanV2]

Have you got *everything* connected? Given the CANBUS in modern cars, I think you're likely chasing shadows if you don't have a entire unit, as it were

C

 

[tonycharente]

Have you got *everything* connected? Given the CANBUS in modern cars, I think you're likely chasing shadows if you don't have a entire unit, as it were

C

Thanks CatmanV2. As far as I know I had everything connected when I had the aircon and accessories panels plugged back in - but some of the (non-window) five switches on the accessories panel were effectively switched on all the time (see my posts on the "Sticky Buttons Sorted Today" subject). Once I've resolved that problem I'll be able to plug the aircon and accessories panels plugged back in and see if that changes anything.

​

 

[CatmanV2]

Thanks CatmanV2. As far as I know I had everything connected when I had the aircon and accessories panels plugged back in - but some of the (non-window) five switches on the accessories panel were effectively switched on all the time (see my posts on the "Sticky Buttons Sorted Today" subject). Once I've resolved that problem I'll be able to plug the aircon and accessories panels plugged back in and see if that changes anything.

​

If it was me, that would be my first step. Get everything connected and back to your original state. Then see if you have the same issue. Others may have a shotcut.

C

 

[DLax69]

If it was me, that would be my first step. Get everything connected and back to your original state. Then see if you have the same issue. Others may have a shotcut.

C

I think that's the only reasonable first step. ALSO, depending on what fluid(s) you may have used to clean the stickies, be certain everything is dry, uncorroded, etc.

 

[tonycharente]

I think that's the only reasonable first step. ALSO, depending on what fluid(s) you may have used to clean the stickies, be certain everything is dry, uncorroded, etc.

Thanks to both CatmanV2 and DLax69.

I used Isopropanol 99.9% alcohol to clean the stickies, which evaporates very quickly - everything left dry and as far as I know not corroded.

I have managed to work out why some of the (non-window) five switches on the accessories panel were effectively switched on all the time (I'll be explaining what the problem was in my posts on the "Sticky Buttons Sorted Today" subject in due course - https://www.sportsmaserati.co.uk/index.php?threads/sticky-buttons-sorted-today.34314/unread&new=1 - but it comes down to all five buttons looking to be all exactly the same when they are in fact somewhat different ). ​

I therefore have been able to plug back in the accessories panel and all the buttons now work - hooray!

However when I tried to turn the engine off with the key it still would not turn off - I had to pull the fuel pump fuse again to stop it.

I had had the "Maserati code" warning light come up (as detailed earlier) and my Launch X431 had given the code as "P1570 Immobilizer". Research into this showed that there is an antenna that checks that you are using the right key and prevents the car from starting if not. In between hours of spraying all my buttons I had removed the cowling above and below the steering wheel to clean them too and I wondered whether I had somehow disturbed this antenna - somehow allowing the engine to start but not letting it be turned off. I just removed the cowling and could see nothing at all untoward. I shall be looking intothis further,but I fear it is a red herring.

So I'm completely stuck for ideas. Plenty of people having problems starting their Maseratis, but I seem to be the only person who can't get his to stop.

All thoughts very welcome, please.
Thanks
Tony

 

[Nibby]

Tony have you done the battery disconnect for half hour yet?
Apologies if this has already been advised.

 

[Zep]

I think you have done the right things so far.

Do things like the radio stay on or the headlamps remain on when you turn the key to the off position? This would indicate that the ignition is staying live when the key is off, which would be the most likely cause. After that I would be pulling the start enable and ignition relays and checking that they aren’t sticking.

 

[tonycharente]

Tony have you done the battery disconnect for half hour yet?
Apologies if this has already been advised.

Thanks Nibby, but yes I have.

 

[tonycharente]

I think you have done the right things so far.

Do things like the radio stay on or the headlamps remain on when you turn the key to the off position? This would indicate that the ignition is staying live when the key is off, which would be the most likely cause. After that I would be pulling the start enable and ignition relays and checking that they aren’t sticking.

Thanks Zep. Yes radio stays on when I turn the key to the off position. Please could you enlighten me on the start enable and ignition relays - in particular where are they to be found? And how to check whether they are sticking, please?

 

[CatmanV2]

Thanks Zep. Yes radio stays on when I turn the key to the off position.

I'd check the ignition switch at this point. Simple to test

C

 

[tonycharente]

I'd check the ignition switch at this point. Simple to test

C

Thanks C. Please could you tell me how to test the ignition switch - given that everything's live even when it's switched off.

 

[CatmanV2]

Thanks C. Please could you tell me how to test the ignition switch - given that everything's live even when it's switched off.

If it was me....

Maserati IGNITION TUMBLER HOLDER SWIT

Maserati Part 82484559 IGNITION TUMBLER HOLDER SWIT

www.eurospares.co.uk

Find the connector an unplug it. My bet is that the ignition will then go off.

There appear to be three cables in that connector (plus there's a small white plug which I think is for the immobiliser antenna)

Get your multimeter on the connectors and move the switch through its two positions. In the off position I would expect there to be no connection between any cables. Position one will short two cables. Position two will short all three.

This is all predicated on the observation that when you turn the key 'off', everything remains 'on' (I may have mis understood this.

Also, I've never actually looked at the 4200 switch, but it's what I'd expect from other switches in cars that I have had issues with.

HTH

C

 

[Zep]

The Cat is right, if things stay on when the key is off, 9 times out of 10 it’s going to be the switch. His method of testing it is also, inexplicably, good as well.

There are 4 wires going to the switch and 4 key positions. At STOP there should be no continuity between any of the wires. If there is, then your switch is goosed.