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Discussion Starter · #1 ·
A couple of weeks ago I was driving along in traffic using Auto mode and she starts beeping and flashing "transmission failure". I noticed the car seemed stuck in one gear, so I manually upshifted it. The car shifted gears and stopped flashing and beeping, we went on our merry way.

Today I was driving about 50 mph in Auto mode, probably was in 6th gear. As I came to a stop she starts beeping and flashing transmission failure, and won't let up. I switched to Manual mode and it showed me gear '5', like she had gotten stuck in that gear while stopping. Would not go into Reverse or Neutral, would not shift gears at all. I shut the car off, started it up, and all was well. Finished my trip around town today with no other issues.

When the car isn't doing this, all transmission/clutch behavior is normal, so there doesn't seem to be anything mechanically wrong. Clutch just checked out at 75% remaining in October.

Any ideas would be welcome on this, my own theory is that the TCU is trying to die on me and is just intermittently failing for now.
 

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My 2005 QP was doing the same thing on an off and sometimes even went into Neutral while cruising with no warning. I finally took it to a Maserati/ Italian car specialist who scanned with the correct type of scanner. NO related faults came up but he said the trans oil was a bit low. So he topped it up (has to be done with car on hoist and slowly from what I saw) and he also adjusted the clutch take-up mechanism. On that front, it has behaved itself since then. It still sometimes pays up if it gets hot and you've been driving a little more spritely, but much better than it was.
 

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Discussion Starter · #3 ·
My 2005 QP was doing the same thing on an off and sometimes even went into Neutral while cruising with no warning. I finally took it to a Maserati/ Italian car specialist who scanned with the correct type of scanner. NO related faults came up but he said the trans oil was a bit low. So he topped it up (has to be done with car on hoist and slowly from what I saw) and he also adjusted the clutch take-up mechanism. On that front, it has behaved itself since then. It still sometimes pays up if it gets hot and you've been driving a little more spritely, but much better than it was.
I'm the furthest thing from a mechanic, but I don't believe your "slightly low fluid" has anything to do with what is going on with your car. It's clearly a Maserati gremlin, like mine.
 

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I'm the furthest thing from a mechanic, but I don't believe your "slightly low fluid" has anything to do with what is going on with your car. It's clearly a Maserati gremlin, like mine.
I am no mechanic either although I do get my hands dirty on my cars as much as I can, I have read in this and other forums that the fluid level in the change mechanism (remembering this is not an auto trans as I am sure you know) has an effect on the sensors which in turn have an effect on what the computer tells the shift mechanism to do. At least that is what I recall.
 

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Discussion Starter · #5 ·
I am no mechanic either although I do get my hands dirty on my cars as much as I can, I have read in this and other forums that the fluid level in the change mechanism (remembering this is not an auto trans as I am sure you know) has an effect on the sensors which in turn have an effect on what the computer tells the shift mechanism to do. At least that is what I recall.
Perhaps, but it doesn't make sense that a car could drive perfectly for weeks if the low fluid is posing a problem, and then suddenly crap out, and then be fine again after a restart. This type of behavior is typical of electrical gremlins, not low fluid levels. My car was completely inspected and checked in late October, and began acting up in November. Did it suddenly spring a leak within days after the inspection? Doubtful.
 

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Perhaps, but it doesn't make sense that a car could drive perfectly for weeks if the low fluid is posing a problem, and then suddenly crap out, and then be fine again after a restart. This type of behavior is typical of electrical gremlins, not low fluid levels. My car was completely inspected and checked in late October, and began acting up in November. Did it suddenly spring a leak within days after the inspection? Doubtful.
You are right.....what talks to the electronics? Sensors. What to sensors sense? Fluid levels, temperatures, driver behaviour, all sorts of things. Just saying.
 

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Sean, if you have a lift, you could check level, and otherwise check if anything is leaking. Of course you likely already have checked the garage floor or usual outdoors parking spot...

I hope, for your sake, it's not the TCU. They are becoming hard to get, I believe.
 

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Discussion Starter · #8 ·
Sean, if you have a lift, you could check level, and otherwise check if anything is leaking. Of course you likely already have checked the garage floor or usual outdoors parking spot...
Actually I haven't yet done so.... isn't there a specific alarm for low F1 fluid on the panel?
 

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Discussion Starter · #10 ·
Sean, if you have a lift, you could check level, and otherwise check if anything is leaking. Of course you likely already have checked the garage floor or usual outdoors parking spot...

I hope, for your sake, it's not the TCU. They are becoming hard to get, I believe.
They are impossible to get, and have been for many years. I'm on my second one, a used unit I was lucky to obtain in 2017. Only the TCU matched to the model year/series will work correctly, the new ones can be ordered but they don't work with the early cars.
 

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I believe the early cars are SOFAST3, not SOFAST3+, and the TCU's may be different. TBH I don't understand what this actually means, i.e. is it so-called firmware versus software? CFC301F.62 might be the correct TCU for you, or is that the correct one for the later SOFAST3+ cars? The SportGT's, 2007, use CFC301F.64.

If you cannot get another TCU, and if you have the stomach for it, consider converting it to 6MT, which I don't think is easy...?
 
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I have replaced one TCU in 10 years..I imagine a lot of the replacements are for dudes throwing parts at cars....They are fairly robust units..Jason
 

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Discussion Starter · #13 ·
The owner of my usual shop, who also works on cars, told me in 2017 that the TCU is a common point of failure if there is some electrical issue with the battery, which is how mine got fried. He told me about his frustrations with trying to get one "fixed" or reprogrammed, and then showed me a box filled with old dead units. He kept them in some hope of one day being able to revive them. I took mine home, still have it around somewhere. He said we were lucky to find a replacement for mine within a week, he had cars in his care that waited six months to find a compatible unit. He tried mine with a new unit at first, but as expected it would not shift beyond gear '3'. I'm not going to get an answer on this until the New Year at this point, we will see.
 

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Sean, I'm not trying to throw you under the bus, but I'd hate for you to continue to have problems and never find solutions based on what this tech told you about that era of TCU. We've talked about this before and I'm with Jason on this - they are fairly durable units that rarely fail. Some were manufactured with firmware that is specific of the NCR version that your MY car has, and based on that some cars are better performing than others. But having a "pile of bad TCUs" in a bucket (your quote from years ago) based on some battery failure is simply hard to believe. Your car has megafuses and a battery ECU that will fry long before a power surge reaches the TCU with any kind of load. I've replaced both primarily due to people charging their cars with a quick charger without disconnecting the battery cables.

Either way, there are a number of things that can cause those symptoms. Hook the car up to a SD3 and read the codes. Any tech with experience in F1s will agree that a combination of codes will point in maybe one or two directions when trying to diagnose. Since your display flashed, that means you were thrown into recovery mode for some reason. There could be internal solenoid leakage, could be the pressure sensor, your accumulator, the actuator tooth could be drifting slightly out of spec, or hell, even one/two of your ABS module sensors could be starting to fail which would cause an F1 to act erratically as it tries to shift into limp mode.

My "guess" would be you have a pressure deprivation problem stemming from the accumulator, EV solenoids or something similar. This is why it runs when restarted, as the pump brings the pressure back up to 50 bar, allowing it to start.
 

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Discussion Starter · #15 ·
It's definitely going in to get figured out, I will report back next month. Problem has happened three times and gets worse each time. The third time it took about 10 minutes before it went away after several restarts. I don't know if this is a coincidence, but all three failures happened when the car was trying to automatically downshift. After I noticed this was true the first two times, I started driving it in Manual mode, and all was well for a couple of days until it crapped out when I was stopping in 3rd gear, when it automatically downshifted it got stuck again and did the failure. Seems like an amazing coincidence, that it could do all my manual shifts but got stuck on the rare one that I let it do on its own in Manual mode.
 

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Discussion Starter · #17 ·
OK well my shop has had the car for a week and put 50 miles on it, they haven't seen it fail yet. They say that the TCU itself has not stored any codes from the past failures, but based on the behavior they believe it is the F-1 pump and/or its relay beginning to fail. A very slight drop in pressure from the F-1 pump will produce the behavior, despite the pump running within spec 99% of the time. They believe if it were any other kind of sensor or issue the failure would be far more frequent and the car would become undriveable, or it would show other behaviors like going into Neutral while driving. Their assessment correlates with the fact that the distinctive sound made by the pump priming when I open the driver door has changed in a way that has worried me lately.
 
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I agree...The pumps are not all that great and when they start to go bad they will work and then not work...I have smacked many with a hammer just to get a car in the shop for pump replacement....Jason
 

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Discussion Starter · #19 ·
Yeah we are at 70,000 miles now, which is plenty for one of those pumps after all.
 

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Is it easy to upgrade to the higher amperage rated F1 pump relay (if indeed the OEM fitment for your year of QPV has the lighter duty one)? I don't think it's just.plug n play, though. And I'm not suggesting the relay is the culprit, though some would consider them a consumable, meriting change-out at interval.
 
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