CHECK ENGINE & SLOW DOWN warnings

There are only 4 things that will trigger a Slowdown warning in the 550:

1. Bad CAT ECU's: (the most common problem and probably yours if they appeared after washing the car). The seal between the cover & body breaks with heat & age and allows moisture in. You can buy the same ones new for 150 GBP from Superformance in the UK, and they'll probably crack open in 10-15 years just like the old ones, but that's not a bad lifetime.

2. Bad CAT thermocouples: Rare, but it happens

3. Bad/blown input channels on the main Motronic ECU's from the CAT ECU's: Even rarer, but it happens (AMHIK!)

4. A truly overheated CAT: The most dangerous condition - test for it with an IR gun pointed at the cat. This shouldn't occur until after the car has been running for awhile. If you get a Slowdown warning immediately after startup, look elsewhere for the problem.

Also, when washing the car, you may have gotten water in the connectors at the CAT ECU's, so it might be worthwhile to remove those, spray them out with some WD-40 and reassemble. If you remove the ECU's themselves from the engine bay, look at that seal on their backsides. If you see any cracks at all, you could try putting them in your wife's oven (shhh!) and just put it on warm (< 200 degrees) and let them sit in there a couple of hours to evaporate all the moisture. Then take them out, run a bead of silicone around that seam, try them & hope for the best.

For the rest of the warnings, I wonder if you got some water into the right hand Motronic ECU from the faulty door seal. That's a well known issue with our cars. Feel around in your passenger footwell and see if it's damp, or pop the sidecover off in the footwell and have a look at the ECU and its connections to see if they're wet or corroded.

 

Alan- You must have some other warning lamp, because there is no tire pressure monitoring system on the 550.

Concur with John. Sounds like she got mad about you spraying her with water. The Motronic DME connectors are very vulnearable to water, too.

 

Terry, the 550 was built with TPMS capability in the dash. A malfunction causing it to come on is possible. There was even a diagnostic plug and software.

 

The problem with diagnosis of the cat temp warning system is to be prepared to diagnose it when a malfunction is taking place. That is nearly impossible so using some logic about how it functions is really what is required.

We know for fact the control modules are junk. The old black epoxy encased units were worse junk than the newer green epoxy. If they are black just save yourself some headaches and replace them. If they ever come on within about 5 minutes of a cold start replace the module. Cat cant get hot that fast. If the lights come on intermittently when the car is fully warmed up there is a possibility the warnings are real. That can get very costly very fast and there is some level of danger involved. In that case take the car directly to a really good Ferrari repair shop to have the running evaluated. It makes no difference if you think it runs well, I have seen way too many catalytic converter fires on cars whose owners insisted they ran fine.


I had a 456 that is nearly mechanically and electrically the same as your car. He had an intermittent electrical problem that manifested itself as a dash malfunction that also caused a Motronic malfunction. The day he came to terms that is was important the car nearly caught fire from overheating cats and it melted a good deal of his exhaust system. It was really expensive to fix.
Don't be that guy.

 

Brian- Thanks, did not know that, obviously.

 

probably from 2000 or 1999?

 

Bernard- They never installed the equipment, just the capability in the instrument panel. They waited for the 575M to come out in late 2001 to install the sensors, antennas, and ECU to provide the TPMS capability.

 

If you have a wiring diagram look at #157 on the legend page. There is also a diagnostic plug for it. They were obviously working that direction but it never happened.

We have had cars with it and I have certainly fixed quite a few and it is one more gadget that my life is better without. It is on par with an electrically adjustable inside rear view mirror.

 

Alan, are you also getting this CHECK ENGINE light staying on after the car has started?

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Have you found the problem yet. My 2000 is doing the same thing. I don't have any stored problems according to the OBD2 but I hit erase anyway, I did at one point get a p1445 code to show up and it is supposed to be about the emissions purge valve but I only got it once and I can't find anything wrong there. I'm cleaning all the conections and getting ready for a computer reset drive cycle. Can anyone tell me how to do a complete drive cycle step by step. I've seen some listed here but I am not sure they are complete.
I think what you are seeing that you thnk is the tire pressure is the suspension display, Mine sometimes comes on at start up after it has been setting for a while but goes right out as soon as I move the car.

 

Ferrari has a listed DC protcol. It did not work for me on 2 different 550's I own but this one is not 550 specific. One 550 (2000) I have a loop I drive and it will set the monitors 100% of the time while the Ferrari protocol will not work. On my other 550 (2001) I just drive the car just a few miles like run an errand to the store and back and it will set the monitors 100% of the time very quickly. So some cars are easier than others. Why I have no clue. Maybe Rifledriver can tell us why that happens.
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Every readiness code process Ferrari ever provided while I was there was shown to be wrong. Bosch is a really terrible company in some ways to deal with and their relationship with Ferrari has never been good. The fact that they don't take this all very seriously does not help.

I recently set every monitor in a 360 sitting in the shop and holding it at 3500 rpm for about 15 minutes. Not supposed to be able to do that. I have done it with 550's just sitting idling in the shop. Not supposed to be able to do that either.

With the exception of some early 360 with bad software almost every car can set them all with a 50 mile freeway drive and if you listen the internet gurus here that just will not work

If you complete that 50 miles and still have not set every monitor I have a few Ben Franklins in my pocket that there is something wrong in that particular system. Just because there is no CEL does not mean all is well. There is a difference between being wrong enough to set a CEL and being right enough to complete a monitor.


Have also seen many instances of CEL and no code on generic scanners.

Bosch in very many ways is like Microsoft. They produce a product with 100 code errors. They fix a few and blow off the rest until the next generation. The next generation fixes 50 more and introduces 55. The Bosch of the 21st century is not the Bosch of the 60's and 70's or even the 80's. The are very popular with the industry because, again like Microsoft, they are delivering a product at a lower price point than everyone else. Something very important too it that they get all their systems precertified with EPA, DOT etc and vastly lowers the approval and certification process for cars to be sold in the USA.


I was once put in touch with who was supposed to be the Bosch guru for American homologated engine management systems. Had an unresolved CEL on a system that seemed to be working perfectly. A, he told me they provided Ferrari with the incorrect wiring diagram for that and he kindly gave me a corrected one and B, his solution was to pull the CEL bulb. He was surprised to find that this was not OK. That was from the people that make it.
I would have been better off dialing 1800-India for product support.

 

Brian, that's hilarious and scary at the same time....

Some states, Texas for example, allow up to two "Not Readies", and from what I understand, it was the result of MB and Jaguar being unable to tell their techs how to get all systems to announce ready.

The 1995 MY is the last to have tailpipe testing where I live, and will have to have that for another 5 years. I used to think that was a bad thing.... That's before I tried to get our Jag to reset.... Having the Motronic 2.7 in the F-car has been a blessing..... Passes emissions testing, with flying colors, even if a CEL is lit...... That may have been what your Bosch guru was thinking, if he was serious about pulling the bulb.

Regards... Mark

 

California 1 not ready and a dyno run tailpipe test on all OBD 2 up to 2000 or so. 1 not ready on newer. Dyno/tailpipe test on all pre 96 back to 74?. Any CEL is a fail.

 

Any CEL is a fail here, too, in NM.

 

Thanks Brian and FBB, This is my first venture into the elactronic cars, all my other cars are from the early 70s and it looks like there is going to be a long learning curve. Thanks for the detailed drive cycle explanations because I'm sure I will be using them a lot. I'm going to take the car out today and see if I can get rid of the check engine light and hope I don't have to go looking for a thermocuple ECU.

Chuck

 

I thought I should start by using Ferrari's preferred drive cycle. Did the complete Ferrari drive cycle and it worked great, until I stopped for lunch about an hour and restarted the car and got the slow down and check engine lights again, there are no fault codes using the OBD2. I guess tomorrow I go to plan "B".

Chuck

 

Just to clarify, any CEL will fail in certain counties in Texas on an OBDII car (96 and newer). We get dyno tested on a car less than 24 years old and pre-OBDII. I don't know if they even look at CEL's on pre-96's, but suspect they don't because there wasn't any standardization on OBD's before 1996, (and, hence no 1996 V-12's???).

Chuck, doubt this will help (I have a different ECU) but, I cleared my CEL's with cleaning and a little WD-40, see:

http://www.ferrarichat.com/forum/456-550-575-sponsored-bradan/398510-5-things-learned-about-456gt.html

I've never had a Slow-down light, but sounds like you have a good handle on what causes those, See Cribbj's post.....

Strange you're getting CEL's and no fault codes???... Assume you're clearing the codes with a scanner??? And does that make the SD and CEL go out?

Regards....Mark

 

The slow down goes away as soon as you move the car, but the CEL stays on even after clearing with the OBD2 scanner. When I disconected the battery overnight and drove it about 4 blocks the CEL light went off until I parked it for about an hour and restarted it. I am going to get up in the air today and clean and check the conections at the cat

 

re: questionable connections

This stuff is supposed to work miracles according to the guys over on the rennlist 928 forum...

Amazon.com: CAIG SK-IN30 DeoxIT Industrial Survival Kit: Sports & Outdoors

 

Alan, were you able to find a solution to the CHECK ENGINE, SLOW DOWN without showing error codes on your 2000 550?

 

Its been a while and forgot to get back to Ferrarichat on this problem. I finally cured my problem that turned out to be a spark plug wire that was not making a good connection on the plug after I did the timing belt change causing the intermittent Slow Down light and Check Engine light without giving a Code number on the OBD2. Now I have to find a way to turn off the suspension light because I turned the ignition switch on and off too many times doing the OBD2 checks. I guess I will have to break down and pay the dealer to turn it off. what an Idiot way to get you into the dealer so they can get their hands in your pocket.

Chuck

 

No worries The suspension light will go out at the first drive when the ECU receives a speed signal.