Whole slew of o2 sensor codes - Replaced Sensors Already

Clear the codes, AND leave the bypass valve operation "normal", do NOT use the Capristo remote control. I suspect many (but not all) of your O2 codes are related to leaving the bypass open. It WILL cause problems, as Ferrari of Seattle tried it with my Capristo muffler and saw the Motronic trying to richen and it threw both codes and slow down lights.
Too little exhaust will pass the pre catalyst O2 sensors with the bypass constantly open, which really messes with the Motronic. The solution would be to move the pre catalyst O2 sensors to the collector on each exhaust manifold...just before where it "splits" to the catalyst and Y pipe.

Drive it for a while and see what (if any) codes come back. Try to drive it this way for at least 50 to 100 miles.

The "no activity" could be a bad connection.

Be absolutely certain you have the correct O2 sensors, and mounted in the correct locations. 13819 pre catalyst, and 13820 post catalyst, and ensure they are connected to the proper connector. People have accidently swapped the connectors front to back...

 

With the 5.2 motronic and the capristo 3 you cannot have the bypass valve open continuously. What happens to the best of my understanding is that with the capristo 3 you will get the majority of your exhaust gases going via the route of the bypass even at idle. This will cause your primary o2 sensors to read a lean mixture going through the main cats and increase fuel into the system. This will cause your 355 to run rich and trigger the slowdown light and the CEL... Ask me how I know... Yep done the same thing as you.

I am now trouble shooting codes that will not go away, not sure if it has anything to do with running the car rich. These are the codes I still have after 950 miles of driving.
P0153, P0133, P0139.

 

That means your sensor is dead. Replace it.

The 2 black wires have 12V on them to heat the O2 sensor
The black and grey wires have the differential signal on them from the sensor.

The OBD2 computer is telling you that it does not sense 12V on the black wires and it does not see any changing activity on the pair of white/grey wires.

 

make sure you have them plugged into the right place

 

Maybe, but check to be certain. Also, it is possible that you have a bad connector...so check the "car side" of the plug, and make sure it all looks good. It is possible to have a bad pin or connector issue. If so, you can order new pins and connectors from Dave Helms at Scuderia Rampante.

As I mentioned in my post #2, I kinda figured the bypass open was possibly the problem. As intoxicating as it sounds, the car won't run right with the valve constantly open. The solution would be to physically move the precat O2 sensors to before the exhaust "splits" at the Y to the cats and bypass. Probably at or just past the merge collector on the exhaust manifolds.

 

Then you need to figure out what signals are being sent to the ECU from the sensors.

Check the signals at the sensor connector.Trace the signals back to the ECU connector (behind the passenger seat firewall). See if the signals are intact. It is best to look at it with an oscilloscope but a DVM in AC mode will do. You can also get an OBD2 scanner that allows you to look at the actual voltage that the ECU is reporting at the OBD2 scanner port.

Somewhere between the O2 sensors and the ECU, the signals have broken. If the signals make it OK to the ECU board, then ... bad news, the ECU is bad.

 

Check the fuses. You likely have a blown fuse for the heater circuits to the o2 sensors. Often this will also result in the air pump not working as well. If fuse is good pay carefull attention to the fusebox itself.

 

You don't have these?
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Things I would check:

1) condition of the catalytic converters
If they are bad going bad the second O2 sensor will throw a code that the exhaust is rich.

2) coolant temperature sensors
If the coolant temp sensors are not sending the proper readings to the ecu the car can run rich/lean.

3) operating temperature if the engine.
If the car is running too cool it will stay in the secondary fuel entrichment mapping, causing the car to continually run rich. This can happen because of a faulty thermostat that is opening too soon, and or stuck open..

4) mass air flow sensor
Make sure the resistance on the mass air flow sensor is withing spec. I don't know what it is for the 5.2 Motronic, but for my 348 they should be set at 383/ohms. Be sure to find out the correct resistance for your 355 before you check it. Less resistance (a low number) will richen up the fuel, and more resistance (a higher number) will lean out the fuel mixture.

 

Here are what the book says about those codes: 0134 and 1115

Both sets of recommendations point to a low signal reading from bank 1 sensor 1. From the look of your OBD2 scanner, Bank1 sensor1 signal seems much lower than bank 2 signals.

If I were you, I would check for bad wire bad connections related to that sensor.
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Use the V scale on the meter, while the egine is running. The O2 sensor is supposed to put out a voltage, not a current.

So if the signals at the sensors are good and identical from left to right, and the ECU is reading a too small of a signal on one side then maybe there is a bad connection from the bad side sensor to the computer. There are several reasons for a bad connection:

corrosion at the various connectors
bad pins at the connector (the pins have lost their springiness)
broken wires through one of the many bends the wires make