HELP 360 Slow Down Light when Cold ? not ecu's or thermocouple ...NEED BIG HELP !!!!!

Cat ECU's monitor cat temperature, not cat efficiency (if you had a cat efficiency issue, you would have a "check engine" light illuminated). I would start looking at the connectors from the thermoprobes for a problem (unlikely if they are new) and most importantly the connectors to the cat ECU. Check each connector for condition of the pins, and actual connection to the wire. I watched my Ferrari tech, and he will back probe each connector with his Fluke tester, wiggling the connection looking for a bad connection. He said it is not uncommon to find a bad pin or wire causing this issue. The whole cat ECU thing is ridiculous. No other car has this system that I am aware of, and 90%+ of the time it is a failure of the monitoring system, not the cats that is causing the "slow down" lights to illuminate.

 

Just read your above response. As luck would have it, my engine light is on steady on my 360. Just as I was coming home from a local drive. Does this mean that my cats will have to replaced? Can't call Ferrari on Sunday
Thanks in advance

 

it's hot in the 310 area code right now

 

These cars are federal OBD2 cars. Why not plug a cheap OBD2 $39.00 harbor freight tester into the diagnostic port? The read out will give you the error code which is standardized by law. Then you can stop guessing and get to the source of the problem or circuit. This sounds like an intermittent temperature related fault. By the way this is the best 39 bucks you will spend for all your cars made after 1995

 

That works for a "check engine" light. You cannot diagnose a "slow down" light with a OBDII code reader. Only an SD2 or SD3 will work for that.

 

Many things can trip the "Check engine" light. It could be many various things that caused it. Only a scan with an SD2/3 or OBDII code reader will tell you for sure.

 

Thank you for the resonse. I have an appointment with L.I. Ferrari for this Thursday. The manual only mentions cat issues for the steady engine light. I hope it is just some sensor issue

 

The cause of the steady engine light on my 360 was due to a gas cap that was not fully tightened. It appears that this is common in 360's.

 

Excellent Scott! Please do post pictures and locations of the grounds. Sounds like you have a good collection of spares now. I would have bought one of those ecu's as I needed one this week...just got it from Ricambi America yesterday.

 

Some times the wiring harness connector pin for the ground at the thermocouple ECU will be faulty. It's pin number 2 the black wire.

 

Those Cat ECU's look similar to the same PITA ones they use on 348's & 355's. Though the connector plugs are different. Those STUPID things are the cause of more trouble than any thing.

Nice post, and thanks for sharing the info. This will definitely help out some 360 owner in the future.

A word of advise. Go get yourself some black silicone and coat the back side of those cat ecu's. They have a tendency to come apart right where the green "seal" attaches to the black housing for the ecu internals. Well what happens then is that moisture gets inside and wreaks havoc with the electronics = false slow down lights & buying new ones. So seal those puppies up good with some silicone before they decide to separate and cause you, or the new owner, more headaches.

 

Sorry to bring up an v old thread.

Scott/Greg

I had one bank shut off half way on my trip to the Netherlands from the UK last week. I limped home and searched on this thread.

I started the car from cold, noted the right hand bank exhaust manifold was cold, removed the strut clip, strut and engine panel, saw that a ground wire that had been soldered onto the negative wire from the cat ecu had a weak connection.

Walked to maplin, picked up a deal on a soldering kit, switched off the main power at front, re soldered, taped up. Put all back together, restarted car and slowdown light gone! Took it for a good thrash and its fine at high rpm too, fixed for sure.

Thanks guys, saved me wasting money on a new thermo couple, which is what I did last time this happened!

 

Hi I have a question : What do you mean "removing and reseating the ground points" ???

Do you just unscrew the 10mm bolt, clean the metal surface and screw it back harder ???

I think my car has the exact same problem as yours (the SLOW DOWN will turn on for a couple of seconds randomly, even when the engine is warm 5 minutes after starting it, and will go way)... Dealer couldn't figure it out... Told me to come back again it the problem persists...

Thanks !

 

Since Spider hasn't been back to answer the question I'll risk jumping in and basically confirm your understanding, yes that's pretty much what it means.

Note, car pictured is a Spider, if yours is a Modena the ECUs and ground points will be a little different but you should be able to locate by reference to the Spider photos.

Best of luck.

 

Thanks FerrariDublin !

Today I removed the right panel to have access to the Cat ECU for the right side catalytic converter (since the dealer told me that the right cat had a temporary increase in temperature) , and removed, cleaned the surface and re-tightened every ground screw and checked on the connectors. Everything seemed fine !

Drove the car and after 5 minutes SLOW DOWN again.
Reduced power, since the ECU cuts 4 cylinders...
Very annoying to drive car on 4 cylinders... Even Minis and Fiats could overtake me !!!

Now CEL is on. So I will visit dealer and hope the situation is resolved.

Before that, I will try to clean the ground point on the left side too, just in case the dealer was wrong about the side and told me by mistake the right instead of the left cat was in trouble...

Let's hope for the best... Keep you posted !

Feel free to drop any suggestions !

Thanks !
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Had a quick read back over this. I believe Spiderscott was probably referring to the ground points on the main Motronic ECU x 2 as opposed to the Car ECU. Might be worth having a go there?

 

Thanks Greg, but I think I did it the right ground points...
Actually I did ALL ground points (or screws that looked like ground points)

This is an old picture attachment that shows the yellow all the screws I removed, cleaned, and tightened back...

I believed the top 2 are the ones you are referring.

Am I right ??

Thanks again !
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