Took the car out on Saturday and SLOW DOWN appeared on the display. Obviously I ignored it assuming a sensor issue, i had just left the house and it wasn't warmed up so was not working the car hard. Hit a cats eye on the road and it made a loud knock - flat tyre. Limped back to petrol station and inflated the tyre to make it home, warning light didn't come back on The car doesn't have TPMS so what was it measuring to realise there was a problem ? ABS / traction control readings different on the side with the flat ?? Whatever it was doing i was quite impressed by. Thanks
Slow Down is a system for registering catalyst problems, not tire pressure, ABS, or ASR problems. While limping and in the gas station, cat temperature went down.
Here are some of the things which cause a SLOW DOWN light: Thermocouple probe on one of the main catalytic converters Thermocouple ECU (one of two). Also known as a Catalyst Temperature Control Station. This amplifies the signal from a thermocouple and sends a voltage to the respective Engine (Motronic) ECU. Fuel mixture issue Faulty catalytic converter Faulty engine (Motronic) ECU Wiring Because the car hadn't warmed up yet, it's more likely to be one of the first two or three items causing issues. You have to identify which engine bank is causing the problem. You will need an OBD2 reader to identify which bank and the nature of the problem. https://www.eurospares.co.uk/Ferrari/550/550_Maranello/PartDiagrams/022/Exhaust_System See items 38 & 39 Some of the components can be expensive. Fortunately, there is a company which sells reliable aftermarket thermocouples (P/N 174674) and thermocouple ECUs (P/N 179278) e.g. https://technistrada.com/ Where are you located?
Your posts are consistently awesome. I’m a nerd and over a year ago bought those 550 thermocouplers just for my spares box incase they became NLA. I admit I have a problem ;-)
I had my 456 sportcats built with the larger bungs for the 550/360 thermocouples in order to use the very nicely manufactured Technistrada probes! Excellent product!
Oh an i thought it had worked out something clever ! Can ran fine the following day - will take it out this weekend and see what it does
My intermittiend SLOW DOWN problem was a poor connection in the connector in the sensor wire into the little converter box on the side of the car under the hood/bonnet. Took me a while to find!
We can all hope to be so lucky! It should be included to progressively check electrical connections throughout the car and reseat connectors periodically. I use this small file on my pinball machine contact points to remove corrosion. Same principle applies to many of the various connections on the car. https://www.marcospecialties.com/pinball-parts/77-PLAST I dont know if its real world applicable, but it is a point of diminishing returns, as you dont want to remove connections too many times, as they could lose their friction point of positive contact.
Probably best to use a product like DeOxit. Not only does it clean, it adds an extra layer of conductive material to the contacts. https://caig.com/deoxit-d-series/
