456 wont start. Need help troubleshooting.

Olhai sobre o imobilizador realmente ele faz o motor girar mais não pega por isso suspeito do imobilizador e vou comprar o By Pass da ECUDoctor

 

reading about the immobilizer it makes the engine start but not start, so I'm asking for the ECUDOCTOR Bypass

 

I guess there are two outputs from the Immobiliser: One for the starter (which is OK) and one going to the RH ECU. I suppose that the signal going to the RH ECU is not good. The Immobiliser wiring is difficult to understand. I see there are at least 2 wire going from the Immobiliser Interface Unit to the RH ECU. I think the signal going to pin 88 of the RH ECU is the unlock signal.

 

Este sinal é codificado, então não consigo identificá-lo com um multímetro. É exatamente isso que preciso saber: se vou liberar o módulo da ECU com o bypass.

 

Understood. I'm just trying to establish what you know about the wiring. Very few people on the forum have wiring diagrams for the 456, so I'm just wondering how you know which wires to check. All the wires on the Immobiliser Interface Unit are black. Do you work for an official Ferrari service centre?

If you find that your flashing LED is caused by a flat battery in the siren, then you will have wasted your money on an alarm bypass.

Have you scanned your Motronic ECUs for faults? Do you have an OBD2 port? Usually if the immobiliser isn't deactivated on Ferraris with this type of immobiliser, you won't be able to do a scan.

 

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Tenho esse diagrama

 

Exibe a falha de código p1625 no scanner

 

Ah, so now it makes sense. You're basically using a diagram I personally created a few years ago for the 456M (and it looks like you added a few of your own notes). I'm surprised it matches the 456GT (5.2) so well. I didn't identify the diagram as an M car.

I don't have a Ferrari code description for P1625, but there are a few posts on FerrariChat mentioning it.... In some posts it relates to the CAN Bus, so I can see why you are looking at pin 86. Strangely, some people with this code also have issues with their O2 sensors. Seems like the code appears from time to time on these cars, but it may not be actually causing your issue.

https://www.ferrarichat.com/forum/posts/142185764/

The CAN Bus issue may be related to the ABS or Automatic Gearbox.

I did make a few mistakes when I was drawing these wiring diagrams (I corrected one diagram recently). This diagram shows the CAN Bus going from the LH Engine connector 24F/27L to ABS Connector 25F:

https://www.dropbox.com/t/h7Vdcoa4RdXUe0Ur

From here it goes to the ABS system and the Auto Gearbox system. I suppose the gearbox CAN wiring might be inhibiting start?

https://www.dropbox.com/t/V1l1IpgpkxD6twOZ

Anyway, I look forward to the results of your Immo delete.

 

Outra dúvida , foi trocado o escapamento refeito inteiro e retirado os sensores do termopar , acredito que não tem relação com o defeito. Pois ja vi pessoas ensinando com um sinal de 1,5 volts pra normalizar o sistema

 

It depends on the type of Thermocouple ECU used. On the newer type, I guess on the 5.2 car, you can put a zener diode and resistor across the Thermcouple ECU pins. See this F355 message thread:

https://www.ferrarichat.com/forum/posts/145063021/


FerrariChat member @wbt now makes these "bypass" connectors if you are not handy with electrics. His company is called Technistrada (in New Zealand).

Here's some assembly tips if you want to do it yourself:

https://www.ferrarichat.com/forum/posts/145451778/

If I disconnect a Thermocouple ECU on my F355, I only get a flashing SD light. i.e. disconnecting either plug on a Thermocouple ECU won't shut down an engine bank.

 

Did you say you have fuel pressure? I was just thinking about the inertia switch in the engine compartment. Sometimes if that fails or is triggered, the pumps stop working. It has a reset switch on it, but it doesn't always work.

I don't think it will stop spark, though.

 

Esta Ferrari não tem interruptor de inércia

 

Vou

Vou usar o resistor e diodo pois fica acesa a luz de slow down

 

My mistake. I was thinking about the M car.

OK. I made some of my own bypass plugs, but it is a lot easier just to buy them if you don't have the tools and patience to make them.

 

Ex

. Vc teria algum diagrama elétrico do módulo do câmbio automático ?

 

Do you mean the internals of the gearbox modules or the wiring going to the modules?

I started to make one for the 456MGTA, but the diagrams had wiring harnesses with wires the same colour, which made it difficult to know which connector pins they went to.

Here is my "work in progress"

https://www.dropbox.com/t/ycFznfB5KlpuUQdN

Of course, the fuses and relays may be different on the 456GTA.... and no one has cross-checked my work.

 

Olá amigos , com o By Pass que a ECUDoctor me forneceu consegui funcionar a 456 GTA , muito bom ouvir novamente o som do 12 cilindros

 

Thanks for the feedback.

 

I bought a bypass from ECUDOCTOR, I just replaced the immobilizer interface with the bypass, and when I started the engine, all 12 cylinders worked again!

 

So this is another interesting case of the Immobiliser allowing cranking, but not unlocking the ECUs... although it's not clear if the issue was with the Motronic ECUs or the Immobiliser ECU.

I have seen wiring issues between the Immobiliser ECU and the RH Motronic ECU on the 360, but I can't recall this happening on a V12. Anyone else?