SDL flashing cold start ( ECU reads 1200 degrees right cat)

Send a PM to drbob101 and he can tell you how to test the thermocouples

 

Could be the cat ECU'S. Mine was flashing on cold start and I replaced the cat ecu's and all is good now.

 

If your car is a 5.2, you have 3 TCU's. One for each CAT and one for the bypass valve

 

Sent you a pm.

You may not have needed new cat ecu as it may be a TC.

There are three cat ecu/ SDECU/ exhaust gas heat transmitters, etc. one is on the left side under the engine bay trim valance and the other two are on the right side down lower behind the wheel on a sub panel.

There are 3 thermocouples , one in each cat right and left and one center after the bypass valve. All components are identical. R/l/c.

The best and in my opinion the only wsy to properly diagnose what's going on is to put a tap on the output line of each ecu and measure the voltage real time under all conditions. Cold warm and hot.

Without doing this you are buying and swapping around $400 units that may not be the issue and relying on a single light that has no locational guidance as to where the issue is.

If your fcar mechanic has 30 years experience and doesn't know this and is just buying boxes on your nickel. Well I'll let you finish that sentence.

 

Bob,

What happened to your write up of the aftermarket SDECU and the source for connector conversion parts to make the aftermarket SDECU Ferrari plug and play? Didn't the aftermarket SDECU work or was it not robust enough to stand the test of time?

 

Carl im running three of the egt boxes in my car now. They work fine as I still have the taps on and watch them but they start out cold at .2-.3v and a blinking sdl until after awhile. The OEM ecu output .5 cold and I am reasonably sure this is the issue. Once the sdl goes out all is well.

I have three new Tc that I made up installed as well. I have reached out to another outfit that makes a similar box at a similar price and ran the issue by a tech there who was very knowledgable about what's going on and of course anything can be built to spec for a price but he did say he was going to see if their stock unit could be programmed to output like the OEM. We got as far as me sending him the output curve and him acknowledging the voltage requirements but that's all.

 

Keep at it Bob. A substitute for the OEM units at that price point would be a major coup in keeping money in owner's pockets instead of stoking retirement plans at Ferrari.

 

Was going to write a whole dissertation here but ill just post this.

For the Op or anyone else that wants to do this in your own car here is a great source for the positaps and insulated spades. He has a $5 minimum on orders and ships right away USPS without crazy shipping charges. I have bought some of our connectors from him as well as crimp tools as well. Instructional stuff on proper crimping also.

No affiliation even though he is a Jersey guy!

Posi-lock and Molex Permaseal Connectors

Motorcycle Spade Terminals

Here is a list of what I would order as his pages dont give direct links to the individual pieces.
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This is someone elses work from a prior thread. FBB can attest to who John is, I'm sorry I don't know but this is the output curve of the SDECUs when functioning properly.

NOTE: When either the ECU 4 port connector or the TC are unplugged, the signal wire reads 5V to the car ECU. This is why merely unplugging them will just complicate things. You can use Jevs flat lined voltage transmitter to fool the ECU with no protection or work through diagnosing and fixing whats wrong
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Drock

You will want to isolate which of the three circuits is giving you the flashing light problem. You can do this by removing each of the TCU and its Thermal Probe, connecting up a test rig and reading the output signals on the bench.

 

Sorry Mitchel but it is much easier to add the taps and test everything in the car. There is no power supply need, the heat generation for the TC is in the car, you don't need to connect multiple things to the ecu on the bench and you don't have to remove what doesn't need to me removed.

It would take anyone all of 5 minutes with the positaps, a known working TC and a voltmeter to know what is working and what isn't.