355 F1 Gearbox Failure Warning Light

Well, at the risk of complicating things, I'll toss this in here.

My car did a funny last fall.
I was driving along and went to down shift from 4th. Nothing happened. Grabbed the handle again....no shift.

As I slowed down the car auto-shifted to third, then second and then 1st as I stopped.

As I left the stop light the paddle shifted fine up...but not down. It shifted down as if I never touched the shifter paddle. It drop down a gear as the car slowed as if in automode.

I took it apart and the micro switch on my down shift paddle is not proper.
The plastic plunger that engages the internal switch was off center and laying at an angle. I squared it up with a needle nose pliers and it works fine. But that wont last.

So I have splurged and bought 30 micro switches for $9.99 on Amazon and will solder a new one in place when I have some time. I will have 29 spares so I should be set for awhile.

Report to follow.

Perhaps you might let the car drive in auto mode to see what works and what doesn't and report back?

 

Ok so mine is exactly the same symptom as original poster. Will shift neutral 1st and 2nd while running. Can only then shift back into neutral to then hit 4th 5th or 6th.
Shifts down fine. Gearbox light on and this only came on after a drive followed by a couple of beeps.
Sat still without engine running I can cycle up and down through all gears no problem and hear the actuator working. Also to add on start up from cold the gearbox primes fine within a few icon flashes,
I reset car and cleared fault. All lights out and took it for another test, sure enough a few yards down the road same thing happened.

Key here is yes the speedo does not work.

I took a look at the wiring for speed sensor and cleaned it but this made no difference

As soon as I get a chance I’ll whip out the sensor from my manual 355 and test it in the F1 car .... it’s the same part.

Will keep you updated

 

Ok next dilemma ....how to remove this speed sensor ????

It looks like a 31 or 32mm is needed to remove, its not a 30mm.

The issue is removing it in situ, I cant see how this is possible. Obviously with the wire coming out of the sensor I cant get a socket on it and there is not much space to get a spanner on it.

However it sounds like others have managed this, just wondering if anyone has a tip or two as i'm currently at a lose

Pictures attached

I have removed the wheel arch and gone in from the side to gain access but still not enough as crossmember etc in the way for a spanner
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Ok fixed it !!

It was indeed the speed sensor p/n 149095 that fixed the issue.

Couple of more bits of helpful info, you need a 32mm socket or 1-1/4 will also fit. No ideally you need a very deep socket so you could fit the sensor cable inside while undoing it. I had a deep 32mm socket but not deep enough, the connector is quite long and just wouldn't fit in the socket and allow the socket to still fit in place. Instead I had to carefully place the two wires beside the sensor and slip the socket over the top, the trick worked as I did it on both my 355's. theres little access but it can be done

Switched the sensor from my manual to F1 car and the fault followed.


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Yup I also notched an impact socket for mine

 

Mine had the same problem.

Here's what i did.
Remove the ground strap first. Then
Disconnect the battery and then reconnect several times - quickly. (via disconnect switch)

This should reset the system.

 

I know this is a fairly old thread now but I have a 1998 UK 355 F1 spider, I drove it for around 20 miles yesterday in sport mode and everything was fine, A bit later on in the day I took it out again it was fine for around 4 miles then I came down a hill with a sharp left turn on a T junction at the bottom I had already selected neutral as I rolled to a stand at the junction then I selected first and pulled away then selected 2nd as I selected 3rd a light on the far left bottom of the dash came on and it would not select 3rd, I pulled over switched off and then back on to see if it cleared but it remained the same I could still only get first and second gear so I managed to get it home I also notice the speedo was pointing at the 100 mph (wishful thinking) and it did not move from that all the way home. I have checked the fluid and topped it up a little, Then did the battery isolator overnight, So today I have gone out and started the car left it to get up to temp and cycle through with the fans running, It selects reverse ok so I rolled it down my driveway selected first then second and that as it still no other gears available but I did notice that the speedo was working again. Next I have tried with just the ignition on no engine running and noted the pump Dash light just flashes twice and it selects all 6 forward and the reverse as it should gears as it should I tried this up and down the gearbox several times. Anyone had the same experience or have an idea could it be the speedo sensor? I don't have the F1 supplement handbook to tell me what the bottom far left red dash light is that came on is indicating, Any help will be gratefully received.

 

Definitely the F1 gearbox failure light.

I'm trying to imagine what kind of fault would produce a stuck speedo. The speedo sensor produces pulses, so why would the speedo sensor be producing a lot of pulses if it was broken? A short or open circuit on the wiring wouldn't seem to. The speedo sensor does have electronic circuits inside it, but you were still having issues after the speedo resumed normal operation.
Anyway, a tutorial on speedo sensor diagnosis and repair is available if required.


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You can remove the sensor & check it on the bench, but usually a modified socket is required to remove it. Some folks fabricate one. You really need a socket to remove it, but the harness gets in the way. If you haven't got a modified socket, you can cut off the harness if you are committed to changing it.

See: https://www.ferrarichat.com/forum/posts/145337234/

I wonder if it's the speedo itself? We know a speed system failure can stop you selecting higher F1 gears. The speedo itself divides the pulse frequency coming from the sensor by two in a microprocessor and sends it to the F1 TCU. I thought that the speedo itself used the normal pulses, but everything else uses the "divide by two" circuit, so why would the speedo itself freeze?

 

Thanks for the info, I am thinking it's the speedo sensor so will order a new one tomorrow, I have looked at a few threads on replacing it, I will also order a deep 32mm socket. It's odd that the speedo was working again when I gave it a brief test yesterday. I have an ICARSOFT V3.0 scanner with 3310 software on it but it will not recognise the car at the moment so need to investigate that too.

 

Did you disable the immobiliser prior to the scan?
If the scanner doesn’t have a Ferrrari selection, use Audi or BMW. Also, sometimes scanners have a Ferrari model selection which doesn’t work but German cars do.

 

Ok so today I replaced the speedo sensor and i still have the problem, I did connect the Icarsoft up again with the Immobiliser disabled, I can select Various Ferrari models from 355 to 430 even mondial it recognises the 2.7 and the 5.2 355 cars but after I run a scan it just says not supported, Unfortunately it will not give and information, Again with the car stationary with the ignition on but engine not running I can select all gears but as soon as I have the car running it will only select 1st 2nd and reverse. I think I will just get the car over to an independent service shop and see what they come up with

 

I would have still tried BMW or Audi on your scanner. It may have given you codes, but not necessarily the right descriptions, but we may have seen those codes before.

Does your independent have a Ferrari SD1 tool or high end tool like the Galileo?

Anyway, I’d be curious to know if your indy comes up with a solution.

 

Well I spent this afternoon replacing both engine and gearbox mounts as a matter of preventative maintenance. Finished everything and took the car out for a 3 mile test drive on the exact same route that I took last week when the gearbox went into limp mode, I am pleased to report back to you all that everything seems to now be fine now The car performed faultlessly.