Aloha All I have been looking at the slow down light at start up for 2 years now, can anyone tell me where the 2 ECU,s are located and how to get to them. My 355 ECUs were easy to find and replace, not these, they hid them good Mahalo John
They are under the covers on each side of the engine compartment. Remove the covers and they are right in the middle of each side.
Thank You, I found them. No cracks like in my 355 ECU,s, they look perfect. Before I order a new one, I read somthing about a possible ground wire that is sometimes the issues, Where is the bolted to.
There is no ground wire issue with the ECU's. Do they have black or green potting material? The updated ECUs have green potting material. You could have bad thermocouples as well. You need to properly diagnose the system.
I picked up a used ECU from a wrecked. auto yard in LA Plug in in to both left and right bank, no change, Slow down lights still came on Blinking after start up I also checked temp of the two cats after 5-10 min iboth around 300 DE Where do I go next???????
You can either do a diagnosis by measuring thermocouple and slow-down ECU voltages (there are many threads on this subject). You can use a Ferrari specific diagnostic computer to look at what fault codes are stored to see which engine bank is causing the slow down light and also look at the thermocouple temperatures. Or you can do the shotgun approach and install two new ECU's and two new thermocouples.
I respectfully disagree with Brian above. I think there are known grounding issues with the ECUs, which you can find discussed in this forum. I had similar problems, swapped ECU to no avail, slow down light was coming on when the engine was cold, so it was not the thermocouples. Eventually after diagnosis the dealership ran an extra ground wire to make sure the ground was good, and I have not had the problem since. Check out this thread. Post 16 has photos of the grounding point for the ECUs: https://www.ferrarichat.com/forum/threads/help-360-slow-down-light-when-cold-not-ecus-or-thermocouple-need-big-help.204156/
I think you need to be careful buying these off ebay because there are so many variants of them. They are different for model years and global markets and also for F1 vs gated. The JN auto tech Aron should be able to help you. That's really our only place to take our cars but thank goodness we have an awesome tech there that cares about our Ferraris. Let me know if you need the contact info.
John: I agree with Kevin above. Take it to Aron. He’s the one who sorted out my Go Slow issue above. Good luck!
I have worked exclusively on Ferrari's for almost 30 years and have yet to see a grounding issue with the slow down lights on a 360. That doesn't mean that there is not a ground issue. If you read my last post, I suggested that he properly diagnose the slow-down light system (rather than just throw parts at it). Every electrical system in a Ferrari (or any car for that matter) needs power and ground. The first part of diagnosing the system is to check power and ground, and then inputs (from the thermocouples) and outputs ( from the ECU's). The ECU's are a known problem area, as they have almost a 100% failure rate for the black potted versions. The green ECU's are better, but can still fail, as well as the thermocouples. As I said before, you can do a proper diagnosis to determine the exact cause of the fault, or just replace everything with new parts and keep your fingers crossed.
Where are you getting your information from? Ferrari has used the same part# 179278 catalyst temperature ECU for every year/version/market of the 360 (coupe, spider, CS and Challenge), as well as the later 456M, 355 2.7/5.2, 550, 575, F50 and Enzo.
Opps I thought the discussion was about the Engine ECU's! Sorry there are a bunch of variants of those for sure. I wasn't aware of the part called the catalyst ECU. I have had my engine side covers off before but did not notice these. What do they do if you don't mind putting some detail in here?
Ferrari started using the slow down light system on cars that had catalytic converters (first on 308GTB). The system uses a thermocouple installed in each catalyst that measures the temperature of the catalyst and sends a corresponding voltage signal to the catalyst ECU. If the temperature exceeds a certain value a "Slow Down" warning light is illuminated on the dash. On later cars, the signal would be sent to the motronic engine ECU which would cut fuel injection/ignition to the overheating engine bank. The idea was to keep an engine miss-fire that would send raw fuel into the catalyst from causing the catalyst to get so hot as to melt down or set the car on fire. The motronic ECU's in the newer cars (like a 360) will have a memory of a catalyst overheat event so you can tell which bank is causing the problem, as the dash display doesn't tell you which bank is overheating. Older cars, like a Testarossa would have two slow down lights, one for bank 1-6 and one for bank 7-12. The funny thing is if it was an ignition miss-fire causing the catalyst to overheat, slowing down would not help, you had to shut the engine off to keep it from melting down.
Brian: Thanks for sharing your knowledge and insights. It is really helpful to have someone of your experience participating in the forum. Thank you!
