p1448 OBII code

Steve,
we need to do a bit more diagnostics to determine your actual problem. I would suggest you swap the thermo probes and power from the center Cat ECU and right side Cat ECU. They are adjacent to each other, so a simple swap. Drive it for a few cycles and see if the problem moves, or stays. If it moves, you probably have a bad Cat ECU. If the problem stays, you need to investigate the functioning of your exhaust valve function some more.

My car had all the Cat ECUs changed to green ones a long time ago, by the previous owner. I had one fail just the same a couple years ago. The green are more reliable, but still not perfectly so.

 

You need to swap both connectors. The ECUs are identical, so if one is bad, you will see the code change from P1448 to probably P1449.

Make sure you clean all the CAT ECU connectors as well as the solenoid connectors. I have seen multiple cases where the solenoid electrical connector was the issue.

 

No. The ECU can be intermittent. It took over a month after I swapped things around to confirm the problem moved, which confirmed a bad cat ECU. I got some great help and advice from Ferrari of Seattle in diagnosing my similar issue.

Here is the full explanation: My problem was the opposite of yours, I had a intermittent "slow down" light on the right side cat, with the Motronic cutting power. Since the dash display on the 5.2 Motronic does not give an indication of which side is bad, I took it to FoS for further diagnosis. They connected it to their SD1 (I think) and it showed no issues (since it was intermittent) and would not act up for them (typical!). Mark Glenwood the service director made the suggestion that it was most likely the right side that is acting up, based on his experience. I have also learned this to be the case, because the right side cat ECU and center cat ECU are most vulnerable to the elements, due to the location, low and on the right side, tucked in under the bumper. Water gets splashed on them driving in the rain, or through puddles, and they can get splashed when washing the car. Good reason to get the Helms gold connector kit and thicker, tighter fitting connector boots. I disconnected mine and had water in the connections! New boots fixed that up. The reason is the oem boots fit loosely, and crack and split. Water runs down the cables and enters through the boots, and gets into the connectors.

Anyway, Mark suggested swapping the connections between the right and center cat ECUs and drive it that way for a while to see if the problem moves. I was having the issue of the "slow down" light almost every drive. He mentioned it might take a while to see the problem move, as the parameter sets in the Motronic are wider for the center cat ECU than the right or left side cat ECU.

So Steve, if you swap the connections, the problem could crop up quickly on the right side, and not take a month like in my instance. But....you never know.

 

I think you would have a much faster diagnosis using my method. It would at least give you a quicker direction of where to look. I think you already said you felt the valve was working normally, and it is pretty obvious when it is not, as you will not hear the normal "howl" at wide open throttle.

 

I am not an expert, but my understanding is on the left and right cats, the cat ECU monitors the temperature of the cat, and detects an overheat situation. Initially it will blink "slow down", but if it gets hot enough the light will be steady and it will shut down that bank of the engine. It may or may not set a "check engine" light fault code.

For the exhaust bypass valve, the cat ECU monitors the temperature that is on bypass, confirming proper operation of the bypass valve. If it is hot when it should be cool, it knows the valve is stuck open and will set a "check engine" light and fault code. Same if it is cold when it should be hot, then it knows the valve is stuck closed, and sets a fault code and CE light.

 

It may shut down the right side bank as I described....it depends on the failure mode. It might just blink. When mine did it, it shut down the right bank, but only for a few seconds, then the light went back out, and all was fine. But it would do it again, 20 or 30 minutes later.

 

The P0410 is confusing. If you are still getting the P1448, I would suspect a bad thermo probe (since it is the only thing we did not change), which is the sending part that connects to the pipe just past the exhaust bypass valve, then has a cable/wire that runs to the Cat ECU.

The reason for the P0410 I have no idea, if the air pump is working fine.

I would return the connectors back to the proper locations. The next step is either swap thermo probes between the right side catalyst and the bypass valve (to see if the problem moves to the right side catalyst)....or just go ahead and buy a new thermo probe, and install it just past the bypass valve. It most likely is bad.

 

Steve,

Keep up the good work!!! Much worse then it looked like from above.

 

I still think it may be related to a bad electrical connection at the solenoid. Did you clean both the connector and the receptacle well? I use a metal brush and contact cleaner. Since the solenoid is activated frequently (every time the valve opens) it builds up oxidation quite rapidly. I had to clean the connections about every 6 months until I installed Dave Helms' gold connector kit. I haven't had a problem since.

-Tom

 

On mine, I could clear the codes and then watch the OBDII reader while wiggling the wires to the thermocouple ECUs and the solenoids and get the P1448 code to appear. That is how I knew it was an electrical issue. It seemed very intermittent while I was driving, but when I moved the wires with my hand the code would appear every time. After trying all the wires one at a time, I narrowed in on the solenoid wire. The contacts were green and very corroded. I finally replaced them with gold connectors to solve the problem. I have also seen the identical problem on another F355.

 

I'm not sure of the answer regarding the bypass valve question. Maybe somebody else could respond to that.

 

If you redo the connectors, you absolutely need to replace the connector boots with the ones from Dave Helms kit. The oem boots fit way too loosely, and allow water intrusion down the wire and into the connector.