Check Engine light and slow down light

Don't have any specific help, but you have found the right site to ask your questions! Although you may have even better luck posting to the 348/355 forum. Welcome to Fchat!

 

If your CELS are on, then you're going open-loop and the O2 sensors are being ignored. In this mode the injection cycle is hard wired in a limp home mode to ensure the engine is not lean (hence why it is running rich). I suspect you have a Motronic 5.2 car... In this limp-home mode you can overheat the cats and the thermocouples, can then trigger a bank shut-down.

As you don't have a standard CAT, I suspect you have a faster flowing one, which will probably allow more hydrocarbons to pass through hence your smelling the exhaust and maybe the "slow down" lights are flashing but not steady on (when steady on, the Vescovini exhaust ECU will eventually shut down the overheating bank). This is a good thing as if you had the stock ones, you'll probably be in danger of fire at worse, or a shut-down at best.

Why you're showing the CELs, I don't know, maybe check that all the O2 connections are in fact OK, and that you're not burning something like oil that is fouling up your O2 sensors. Also ensure you use good quality BOSCH ones and of the right type (I believe universal Zirconia, Thimble type, 4 wires should do).

Post in the 355/348 forum and you'll find some more specialized knowledge...

Good luck and welcome!

Marco

 

9 times out of 10 it is the cat ecu's!!!

 

A friend of mine is also a former Ferrari tech and agrees.

Here is my recent experience:

http://www.ferrarichat.com/forum/showthread.php?t=200968

 

Did you have it towed to a dealer?
If not, I think it is time to step back and gather some diagnostic info. One you can do yourself is to read the check engine code and see what the computer is trying to tell you. Also, look for any loose electrical connections in the engine bay (for example, the electrical connections at the MAF sensors).



Lou

 

I have never known a code all by itself to cause the car to not start, but that doesn't mean there aren't some very serious ones that would do this. It would be a reasonable experiment to recycle the power causing the computers to reset, but if you disconnect the battery to clear the code before reading it, then you will lose the information that the computer was trying to give you. I would read the code first, then decide if I felt comfortable in clearing it and starting the car. It is an expensive engine.

Could the battery be weak? Does it have enough power to run the headlights?


Lou

 

Ho boy - this is a tough one - but lets start at the top and work down. First, after reading your posts, I sense your car is an OBD II model. On Board Diagnostics. 1996 forward. It would be if it was first sold in the USofA. That said, blinking CEL or MIL (malfunction indicator light) means CAT trouble of the first degree - caused by an engine miss (more later). The most worstest of evils that will kill a cat faster than anything. By kill it, I don’t mean by poisoning it as if you would with the use leaded fuel, springing a head gasket leak and soaking it with coolant or spritzing it with silicon - I mean by over heating and melting it. It may be you have melted the cat matrix into solid goo that is similar to a potato in the exhaust pipe.

So - does your car still have cats?

OBD II is VERY smart - it is NOT an emission checker, rather it is a device that runs and double checks 11 monitors. It uses a rational theory program if all monitors are run to completion, the emissions will be low. Smelling raw fuel, HC, is NOT a good sign.

This will require a sophisticated scan tool that can be plugged into the system and look for fault codes. No fault code that I know of will prevent the engine from running. I could be wrong. BUT the important thing here is not just the code but what was happening when the code was set - and that is found in the Freeze Frame data. VERY important aspect. Don’t know what state you are in but if it requires a smog check any GOOD shop and technician with a good scan tool would be able to diagnose the problem.

As for an engine miss - Your OBD II engine is so sophisticated it can sense when the crankshaft slows down inbetween cylinder firings. It uses a crankshaft senor (Google Misfire Monitor) that sends a signal to the PCM, powertrain control module, based on engine speed. If the signals are constant in frequency and amplitude then all is well. If the the PCM senses a slow down in frequency or amplitude it means that the crankshaft has slowed down and this will be interpreted as a misfire. The PCM keeps track of the misfires in blocks of 3200 rpms which is further divided into blocks of 200's. If, in any of the 200 block segments, the misfires reach a predetermined cat damaging level, it commands the MIL to blink. This is where I think you were when all went quiet.

SO - what you want is FREEZE FRAME data. Not just the the DTC or diagnostic trouble codes. What went on and when. Do not disconnect your battery. You may loose that very important bit of data.

Sorry you have this problem. Hope you get to the bottom of it. Please keep us posted.

Oward
DOUG

 

Here's my last shot at this since I've never owned a 355 and we don't know the fault code that is causing the check engine light: look for a main electrical harness connector in the engine compartment along the driver side upper subframe rail. If it is like previous models, there is a large plastic connector there. Unscrew it, clean the connection if needed, and reseat the connection. This connection caused me similar trouble on a previous car, but I can't confirm that the 355 uses the same setup. A quick look at an online parts catalog seemed to show a harness going in that direction, but it wasn't clear.


Lou

 

Don't let it get you down....Your Ferrari mechanic will sort it out and you will be up and running soon and have forgotten all about this day. A 355 is a pleasure to own/drive. You just bought it so the previous owner may have over looked some things. Take care of it and you will enjoy many happy trouble free miles....

 

I would check power to the ignition switch itself. You may simply have a bad ignition switch that needs replacing.

 

Removal of the steering column cover is not too difficult. Lower the wheel adjustment first, then there should be a couple screws from below.