my first slow down light =(

Hi Tim1137,
Just got rid of SD on my 360 by replacing part 179278 which is cat ECU.
Before replacing, I checked the contact points of Thermacouple connecting to cat ECU.
My situation could be different from yours. The SD occur somtimes during start up or after driving for 10 mins or so. It first started flickering then constant SD.
Aldous Voice has a wide commentary on 360 SD. Very helpful tips in his blog.
Hope this helps

 

Switch the box to the other side. See if the code switches to P0422. If it does, bad box.. if it doesn't I'd check the thermocouple on that bank with a multimeter and compare to the other side.

 

Tim, I take it that this is a 360?
CEL light won't go off because there is probably another code in the other ECU. You have two ecu in your car. Generic OBD2 reader will not pick it up.
I struggle on this when I first got my car. I kept questioning myself, if there is no code then CEL light should go off, why is it ON!!!!. Well, come to find out there is another code from the other ECU...
Check it again with a better OBD2 scanner, Tim.

 

There must be moisture in the boxes! Green is the newer model part. Check your 02 sensors as well part no. 180915 and also part no. 182837. The cat ECU and the sensors tend to go bad. Also, if SD happens after long period of driving, then it could be the ignition coils. There are instances also like your gas cap is not properly tighened or you might have top up too much cylinder oil, these may trigger SD light.

 

Tim, if you flip your Cat ECU, you have to do a proper reset, meaning turning the truck switch off and leave overnight. Insert car key for 30secs, re-insert and turn to on and leave for 30secs. Turn off and take key out and wait another 30 secs. Thereafter start your car after check OK. Let it idle for 10mins.
Specific driving instructions. Drive car in 3rd or 4th gear 2000-2500rpm for 3 n half miles. Shift to 4th gear and increase speed to 4500rpm for 30 secs.Then decrease engine speed to 2000 without braking shifting into neutral without braking. Gently stop the car and let it idle for 5 mins without touching throttle. Switch engine off and remove key for 5 mins. Restart engine and drive normally for 10 mins.
If you still have SD from this remapping, then it is difinitely defective parts.

 

Tim. May I ask if you look at both ecu and not just one? Your bank 1 stored p1446, does this mean bank 2 have no code?
The "slow down" light you got to start out with is obviously relate to p1446. High temp in cat converter system will trigger "slow down" light.
I would suggest you don't condeem anything just yet, Ferrari parts aren't cheap. There is a way to look at temp sensor failure in general. (temperature in relation with resistance of sensor during failure).
Swapping from bank1 to bank2 is a good idea to isolate failed part/component, but it only accurate if you can look at dual data. Meaning both ECU (at the same time would be best) Yes, I know, without an sd2 is almost difficult. But, you rather pay a shop for those freeze frame data then mistakenly replace part(s) that you don't need.

 

Tim, I had the same scenario where after reset and all the specific instructions, the SD appeared within 10 mins. I did not have a generic reader neither did I go to a shop with a OBDII. After a few resets flip flopping cat ecu and spark plug changes and with the help of Aldous Voice, I took a gamble and replace both ECU and no SD light so far. There is no way after 10 mins of driving, the cats will hit 1700deg. in temp. Will the SD light return, I don't know but its doing fine so far. Hope this helps.

 

Id move it back and if it follows.. Replace it if it were me. no way the error follows twice and it reached max temp in a few min. Cat isn't glowing is it?

 

I thought I am the only one fear of paying high price on my toy...LOL, glad you feel the same. This is the reason why I keep encourage everyone not to be a "SWAP TECH", there is always a way to diagnose and narrow down your car problem, sometimes its not easy because lack of knowlege and equipement...But needless to say, there are lots of intellent individual from this forum can help, and I thank everyone that participate....
Well, good luck to you buddy...Your finding and sharing well help us all.
THANK YOU AGAIN...

 

I have an extra CAT ecu if you need it...cheap.

 

Nice. Thanks for the update!

 

Excellent! When I first got my car, I had this same problem and it was tough to diagnose because the ECUs did not fail to the point of throwing any codes. All I got was a Slow Down that only flickered intermittently when driving really hard. But if I continued to drive hard, it would then come on steady, and at the same time dial back the engine power. But reading the temp with a remote thermometer revealed no signs of cat overheating (which is what the Slow Down light is supposed to protect against). I finally traced the problem to the ECUs; both needed replacement, and one of the thermocouples in the cats needed replacement, too. Problem solved.