My QP5 won't start!!

[simonlee]

So, I'm currently having a huge problem with my quattroporte v. It all started 3 months ago. I shifted gear from 3rd to 1st too fast, and the car showed me the transmission warning light(red)
I was hoping to get rid of the warning light, so I turned off the engine, and pulled the key out and restarted. And the warning light was gone.

Now the problem starts. Big one. 2 months after the event that I mentioned, the car started to show me the "gear unavailable" sign. Not all the time, but only when I downshift from 3rd gear to 2nd gear on 2100 rpm or lower. It use to shift gear after a 1 second so I just eognored the sign and kept using for 2 weeks. But it started to bother me because of the downshift was not working for a second, so I started to fix this.
First thingtI tried was changing the F1 hydraulic pump fluid. I've removed the fluid that was already inside, and filled with "pentoshin che11s".

Nothing changed. So I asked my maserati macanic about this, and he replied it must be the hydraulic unit of F1 transmission. So I bought few things from scuderia and Eurospars.
1. Complete clutch
2. Centor ball bearing
3. F1 pump motor
4. Hydraulic unit
5. Clutch position sensor

After this, I went to up hill winding with granturismo, r8. But this time the clutch slipped and went in to natural when I downshift from 3rd to 2nd. (Happened 2 times) So I decided to reposition the clutch and check the remaining of clutch.

2 weeks after changing the F1 pump fluid, I decided to check the clutch remaining and adjust.
So I went to my friend's macanic, (who has launched X 431 pro- I guess)

After he checked the remaining on my car, he re started my car. BUT IT WOULD NOT START!!! So we checked the codes. I can't remember but there was no break pressure..? (Not sure that is low or no but the brake is correct)
And few other that was related with a front suspension solenoid.

Even after 2 hours the car did not start, so I send my car and the parts to my maserati macanic.
He replaced all the parts that I mentioned, but the car sill won't start. So I changed the brake pedal switch, but still won't work.

PLZ HELP!!! Did anyone had a same experience like me or is there someone who can help me with this?

 

[CatmanV2]

I shifted gear from 3rd to 1st too fast,

You can't shift 'too fast' The TCU will prevent a downshift that causes an over rev (or an upshift that would cause a stall) so no blame on you.
I think it's going to need live data while trying to start to ascertain why its not getting PTS. But I'm pretty damned sure you didn't all those parts.
I expect one of the experts will be along shortly

C

 

[simonlee]

You can't shift 'too fast' The TCU will prevent a downshift that causes an over rev (or an upshift that would cause a stall) so no blame on you.
I think it's going to need live data while trying to start to ascertain why its not getting PTS. But I'm pretty damned sure you didn't all those parts.
I expect one of the experts will be along shortly

C

Well...I did give all those parts to my macanic hoping that will work. But didn't.. thanks 4 the reply though!!

 

[Zep]

So the way it works on a duo select is that when the key is turned to start the car that request goes to the TCU, when the TCU is satisfied that the clutch is open, it gives a signal to a relay under the bonnet which in turn feeds the starter relay which then spins the starter.

If the TCU is not happy, you usually get a “check transmission, go to dealer” message.

If the signal from the TCU is not making it to the relay (for example, because the tracker is interrupting it) then you get no faults but no starts.

Can you select gears (1st and Reverse) with the ignition on but the engine off? If so, when you go to start with it in gear, does it drop out of gear but then not start?

 

[simonlee]

So the way it works on a duo select is that when the key is turned to start the car that request goes to the TCU, when the TCU is satisfied that the clutch is open, it gives a signal to a relay under the bonnet which in turn feeds the starter relay which then spins the starter.

If the TCU is not happy, you usually get a “check transmission, go to dealer” message.

If the signal from the TCU is not making it to the relay (for example, because the tracker is interrupting it) then you get no faults but no starts.

Can you select gears (1st and Reverse) with the ignition on but the engine off? If so, when you go to start with it in gear, does it drop out of gear but then not start?

Currently, the clutch is in nature. I've pulled out with scanner from 1st because I had to push and put it on a lift.
F1 pump works, I can hear the sound of it running. But now after the changes of few parts, it won't move from N unless I force it with a scanner. And when I turn the key on, it just shows gear unavailable with green N on the screen.

 

[Zep]

From this distance it doesn’t sound like a problem with the start signal.

Has the clutch been set up? What is the PIS setting?

 

[simonlee]

From this distance it doesn’t sound like a problem with the start signal.

Has the clutch been set up? What is the PIS setting?

Well...I don't know the PIS settings with this. But I finally got the codes!!!

 

[simonlee]

Now I have p1751, p1752, p1756, p1757, p1758 5 error codes on the scanner. But still no start, no crank.

PLZ HELP

 

[Zep]

Short circuit or wiring issue, which is odd as you can select them manually.

 

[simonlee]

View attachment 121438
View attachment 121439

Short circuit or wiring issue, which is odd as you can select them manually.

Thanks!! I'll check these as soon as possible

 

[cheburator]

Sounds to me your TCU is bricked up. Some dodgy copies of Launch/Diagzone software do this. Nothing but a re-flash with “clean” factory software will solve your issue. Or a new/used TCU. Whatever you do, DO NOT transfer your old data on the new TCU. It will be bricked up too. You really have to start a fresh - a reflashed TCU and a knowledgeable specialist with an SD3 setting up your new clutch from scratch, without using data from your bricked up TCU. I was there and had very similar problems to you. All solved now, but it wasn’t easy and the solution surpsised two very well regarded specialists on here!