Heads up to F1 owners

I thought I'd share a potential lesson learned that I encountered which will hopefully avoid you being stuck. I've had my 98 F1 for several years now and have never really had any issues with it. Last weekend on a drive the speedometer went dead and I learned (the hard way) that this impacts the gearbox and will cause the car to go into limp home mode which means you basically can not shift out of second gear. The "potential" culprit was the speed sensor on the gearbox. Notice I say potential because I don't know if we'll ever know 100% sure if that is the problem but we did get the error code on the SD2 for this critter. It's a $200 part but I replaced it even though we may have been able to get by with just cleaning it simply for peace of mind. I would recommend adding this to the relay of things to periodically check and potentially replace. Like the relay, you don't know you have an issue until it's too late so IMO it's better to just replace it every 5 years or so and not have the worry. It's part #34 on the diagram. BTW, the relay is part #155437 and I replace mine every 2 years. Hope this helps!

Speed sensor - 149095
Gasket for sensor - 102634460
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It's a quite classical issue on the 355 F1.

 

Even on the manual trans cars, if the speedo sender fails, you also will get a suspension warning light as well. The suspension ECU needs a speed signal to work properly.

 

Thanks Monte. Have heard rumblings about this, been fortunate thus far. Sounds like a "while doing a major..." kind of item. My list keeps growing!

John

 

Monte- Similar problems have surfaced on the 575M, too. The last time it happened to an FChatter, just cleaning the connectors and sensor head fixed it. I do not blame you for changing it, though, yours is a bit older than the ones in the 575s, so preempting was a good idea.

Incidentally, the later F1 cars have a separate angular speed sensor, in addition to the one providing data to the Motronic ECU.

Taz
Terry Phillips

 

All these potential things that can go wrong really scare me. That is why these posts are invaluable. Just changed my relay to the upgraded one Juri is selling. I guess I should be proactive and change the speed sensor next time my car is is for service. The last thing I would want is to be stranded and have to call a flatbed...ugh...the embarrassment!

 

For the record, I bought a new one and installed today. I have owned the car for over 3 years. I have all records and could find no indication it had ever been replaced.

Old relay looked EXACTLY the same as the new one, indistiguishable. Not a mark, discoloration, nada. Appeared as new. Maybe the relays can fail, but I dated the new one and kept the old one. I don't think I really prevented anything.

 

Open the old one and examine the contacts with a 8x or 10x lupe, or did you already? That might tell you more

 

Check resistance old vs new. That's where you would see any difference.