355 F355 SDL

Hey guys, it's been a while that my 5.2 has the Slow Down Light flash on the dash and this is starting to get quite annoying to look at.

I know that people have already discussed about the SDL but I don't really what could be the reason on my car.

I'm running since almost two years with a full straight pipes dekat exhaust and I've never had a single problem with it, no lights or stuff like that. In recent times I had a problem with the engine ECU which led the engine to run just 1 bank - I fixed the problem by sending the ECU to an ex Ferrari mechanic who did his magic to make it go back to 8 cylinders; I want to specify that nothing was changed or replaced on my car, just the ECU was fixed.

The light has popped up for the first time the day the car was fixed and there's no way to take it out so.. what could it be? Maybe just now the car realised I'm driving without the catalysts? The car runs perfect and I just want to get rid of that annoying light.

 

Since there is no catalytic converter anymore, whatever the light is telling you is bogust. You can...

1. Remove the light from the dashboard
2. Put a piece of black tape over the light.
3. Send it back to the ex-Ferrari-mechanic and have him program out the portion of the ECU firmware that turns on the SDL

Pick your poison among the three.

 

Ahah I'm already doing the Step 2. Honestly I don't want to remove any light as I couldn't tell if there's a real potential problem in the future.

I've already sent the ECU back to the mechanic once and the SDL is still there.

 

There's a better way! Get the Technistrada dummy load senders. This is what I did. No more problems running bypass pipes. It's the best solution since, with cats removed, the SDL system for the main cats no longer serves a purpose.

https://technistrada.com/catalytic-slow-down-ecus/dummy-load-sdl-bypass---not-for-installation-into-vehicles-equipped-with-catalytic-converters

 

I would buy the dummy ECUs just to see if the problem goes away. If it doesn't, then you know your ECU is still faulty (or wiring to the ECU). Do you know which bank the problem is on?

If you can't wait for the dummy ECUs to arrive, make your own:

https://www.ferrarichat.com/forum/threads/simple-2-7-slow-down-ecu-replacement-only-for-no-cats.538719/

 

Thanks guys, just ordered one and see if the problem gets fixed. Honestly I can't remember which bank was off, it happened months ago and lost a lot of time to repair the ECU (first with the useless Bosch Germany who kept the ECU 2 months for nothing and then I found this ex Ferrari mechanic).

 

Right guys, just found some time to install the Technistrada dummy load senders and.. SD light is still there. Do I need to disconnect also the other pin of the ECU?

Is the light supposed to disappear immediately or it takes some time? Because once I installed it I just kept it at idle for a minute and the light was still there.

Can't remember which bank was faulty, the only thing I know is that prior that problem my car was running dekat without any lights on, once the problem to the bank was fixed the light popped up.
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Not sure what you mean. You just disconnect the top plug of each thermocouple ECU and plug the dummy loads into the Motronic ECU wiring that previously went to the thermocouple ECUs:

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The ECU then ignores the cat exhaust temperatures and faults with the thermocouples and thermocouple ECUs. No pin removal required.

I can't remember if you need to reset the fault codes in the Motronics ECU to extinuish the SDL. Do you have a OBD scanner?

If the reset doesn't help, then there may be an exhaust bypass valve issue or a fault with the wiring between the dummy loads and the Motronic ECU.

Do you have an ohmmeter to check the wiring?

 

Are you 100% sure that on the right side you plugged the dummy load sensor into the correct wiring? If you plug into the bypass you will get SDL. Very easy mistake. In my experience it takes a little driving before the light shuts itself off.

 

Yes both were plugged in the correct wiring, just did a 14km drive with the car heated up and the light is still there, this is getting annoying


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US 5.2 cars have 3 SDECU locations. All will trigger SDL.

 

Mine's EU spec as I live in Italy.

 

Is it possible that the third bypass location on the harness is there on the right side and you plugged the dummy into it by mistake?

I don’t know euro spec but in US I would clear all codes with OBD reader for starters. Do you have OBD?

 

Nope I've plugged them both in the engine bay where the ECU cats are located - pic above

I don't have an OBD but I'll ask to a friend for that

 

It’s hard to tell from your photos where your cat ECUs are located. I’m not familiar with the location of the RH cat ECU on a Euro car. On USA cars, there are two ECUs close to each other near the Secondary Air pump. I’m not even sure the Euro car has a secondary air pump.

For the OBD reset, you’ll need a 3-pin Fiat OBD adaptor. The Euro F355 doesn’t have a standard 16 pin OBD port. The scanner needs to be plugged into one of the Motronic ECU connectors behind the passenger seat.

 

SDL's aren't part of the OBD system so using an OBD reader won't work here.

OP, again, it sounds to me like you haven't verified whether you've plugged the doohickey into the right socket. There are two cat ECU's on the right side of the car, one for the right side main cat, the other for the bypass valve thermocouple. The two plugs look identical, they're right next to each other, they both plug into identical ECU's that are also right next to each other, and the doohickey will fit on either one. So if you haven't actually verified that you did this correctly.......

 

He has a euro spec car. There is no bypass SDECU in euro spec cars.

 

It's the Motronic ECU which illuminates the SDLs on 355's. Codes P1446 and P1454 are, specifically, "Catalyst Protection Active" codes.

Other SD system codes are P1445 and P1449 (and P1448 on US cars). The definition of these faults is not clear as the terminology used is "plaus (?)/min/max". Is this "plausibility"... i.e. an impossible voltage value from the thermocouple ECUs? I assume min is too low (for an operating engine)? max could be overtemperature or an implausibly too high value (?). If Marco has an SDL with the dummy loads in place, then all it can be is faulty wiring, a power issue or a Motronic ECU fault.

 

Targatime, not true. The activation of the SDL causes a CEL code (ferrari specific) and must be cleared by a OBD2 or its equivalent scanner.

 

Disconnect the car battery for a few minutes and reconnect. The light usually goes away. Failing that and assuming the dummies are plugged into the correct connectors (on EU cars it's hard to get wrong) then it's either a fault in the wire leading from Cat ECU to Motronic, or a failed motronic unit input pin.

 

In the US, the fault codes are in memory and cannot be erased by a power down cut. I am not sure about Eu version.

 

I stand corrected. I blame my CRS disease (Can't Remember ****). Could have sworn that SDL was separate from OBD.