"Slow Down" light on 550?

Your catalytic convertor is heating up too much is usually the tyrant for that. Just give your dealer a call and see if they can diagnose on the phone. They will usually give you an idea over the phone but still will suggest you take it in.

 

Either that or you have not warmed up enough. I get a "SLOW DOWN" when I am going less than 5 mph in the parking lot. I just wait until the beast is warm. Use the oil temp gaunge.

Never drive less then 12 cylinders

 

It's hard to say w/o a computer hooked up to it.

I doubt your cats are overheating. On a 550, first they will flash at ~80% critical temperature, and then they will turn on solid. My light came on solid and the car decided to cut power when i was on the freeway once (ironic, the one time I needed it to be reliable), and I checked the cats: cool as the morning air.

Turns out that the thermocoupler ecu had losts its mind a bit, just a quirk, and they didnt even need to replace them.

If it happens just this once, let it go. I wouldn't worry. But if you see the light come on again, pull over and *catrefully* try to see if you can tell if the cats are hot. Maybe stick a piece of paper there and see if it lights up. Also, remember that it should flash first.

--Dan

 

As much as I love the Shark, Ferraris and electronics don't mix. The !$#@$!@ check engine light seems to work on a random number generator. I had to have the seat belt light disconnected because the damn thing would come on if I made a hard right turn. The only way to turn it off was to undo the seat belt.

Of course, none of this matters when romping from 3rd to 4th....

 

That's a wierd one. I think Ferrari secretly contracted out their electronics to an 80 yr old Lucas engineer.

--Dan

 

Do you systematically wait for the 'Check ok' message to come up on the dash indicator before turning the engine on ?
My dealer insisted at delivery that the self-check time be respected otherwise you may experience the wonders of italian gizmotronics ... such as spurious "slow down" lights.

Btw, page 3-34 does exist in my edition of my manual (edition 1a January 2001) and indeed refers to excessive temp in the exhaust system.

 

Seems to be a common problem. I had both thermocouple units changed to fix the problem.

 

Just for kicks and if you don't mind sharing, what was the parts/labour cost to change these thermocouplers ? Any warranty coverage ?

 

I'll check the invoices and let you know. Wasn't big dollars though, less than $1500AUD ($1000USD) for both units fitted. They are easy to access, being mounted in the engine bay.

 

I guess I have to apologize for my humble reference points. A 1K$ invoice for thermocouplers which should be reliable in the first place is not exactly what I'd call peanuts.

A quick story: I own a '99 Audi S4 biturbo, bought new. Great car except that it warps brake rotors. This winter, at 70'000km, the water pump broke down. Car is 4.5y old. Audi came to my house, picked up the car, and offered spontaneously to replace the water pump for free, considering it was abnormal to have any such failure on their cars.
When the car was 1y old, they made a recall because a protection steel pad under the engine was at risk to break loose, operation required taking the engine out (2 days of work).

Responsible and proactive attitude towards known quality problems, and responsible attitude towards abnormal failures.

Should not we expect MORE from a company who's cars cost 4x as much ?

 

Thermocouplers and all "emissions" related items are covered under a 7 year warranty by law, at least here. So if they are bad, they get changed for free. And every maranello is within 7 years right now...

--Dan

 

Has anyone blown a cat on their 550? If so did you repair or replace (oem or aftermarket)?

We were on a driving trip and everything was great. Went about 150 miles and stopped to top off with gas. When we got back on the road the car seemed sluggish. Then I got the slow down light when I was accerlating the car (aound the speed limit ). I slowed down thinking something was not right. Then the car started sounding like a Volkswagen Beetle. We limped back to the town where we got gas and had it transported back home. Today, I found out I blew out one cat and the other is looking to go. FYI, '98 550 with 14,700 miles.

Also, this is not the end of the story. Let's just say we started with a 550, 355, Countach and Z8. Finished with a Z8 and CLS500.

 

I had the same problem on my 456 and it was traced down to the relay that controls the thermocouple.
I would strongly recommned that you start from there, as they are inexpensive to buy and easy to replace.
To test it you can just switch them around (left to right and viceversa) and see what happens.
On the 456 they are under the hood, just above the side vents; I do not know where they are in the 550, but they must be in a similar location.
Good luck.

 

Hello - I am curious - it's been about 2 months now, what is the current situation? In addition to the Slow Down light, did the Check Engine Light or Malfunction Indicator Light (MIL) light up?

Thanks
DOUG

 

My car started doing this too, but upon hooking up an SD2, what we found is that it's actually the battery which is getting old and whose voltage dips when the starter motor runs.