About that "Heater Circuit Shorted": Firstly, I have no specific knowledge of 355 ECUs but as I do design ECUs this might be of use: Generally the heaters on all the O2 sensors are fed from a common 12 volt supply, via a fuse. The ECU is connected to the negative side of the sensors. This code is generated when no voltage is detected on any of the sensor heater wires. So it can be misleading. It can be a blown fuse or an open circuit which affects the common part of the heater circuit. The reason for the description "shorted" is really because it assumes a short has blown the fuse. An "open" code is generated when one sensor wire has no voltage. Are schematics available for the 355?
Not sure that is correct the 355 but in any event, ketel was instructed to check the fuses many, many posts ago. It's anyone's guess if he ever bothered to do so.
Hard to say, at first startup it fired up right away and *seemed* to idle and pull from a stop relatively well but the poor running condition I've been complaining of. ketel
True, I mangled the first 2-prong connector I attempted. I was not able to get the old pins/terminals out in order to clean and reuse the connector housing. However, I never used that connector again. Instead I purchased half a dozen new 2-prong connectors at Napa auto parts, removed the harness innards, and used those fresh connectors in cases where I was unable to reuse the old connectors. The new connector housing snapped in just fine. ketel
If your car is running ok at initial startup with the codes cleared, the ECU is running your car with only a single input variable , the coolant temp sensor. This is when your car should be running ok. This is before it enters "closed loop" and is looking for input from the o2 sensors. Does anyone know where you can get a diagnostic manual for the 355 Motronic ecu? The 512tr references a "diagnostic manual no 14," but I have yet to find anyone that has it. Both cars share the same ecu so I thought I would ask. I really feel this manual would provide some answers as to how the ecu functions through the start up process.
Andyww says he designs ECU's. Since we don't know how the 355ECU functions perhaps taking the wag of someone who "designs" ECU's is a pretty good hypothesis. Thanks for the input. Second checking Ferrari fuses tells you sometimes very little because Ferrari fuseboxes are such cr@p. You can have a perfect fuse and a cr@p circuit right in the box. In fact I am rebuilding one right now. Andyww, As an ECU designer what can you say about flashing or altering 5.2 motronics? There are shops in Europe who claim to do this as easy as we do it for modern corvettes. Here in the U.S.A. no one seems to do it close to SoCal. There are Ferrari Challenge guys who claim reflashed ECU's but they are thin on proof and thin on winning and thin on sources. I suspect there are no reflashers around. Do you know any Socal vendors who can do this? In 348 world with the 2.7 Motronics NoDoubt cracked that code and was able to flash new prom chips but he says the 5.2 is a different animal and he does not understand it. Comments perhaps by PM so as to not derail this thread?
Chubba, that is going to do nothing to help ketel get his car running, and is better left for AFTER he has his running problem sorted. My suggestions are these: 1) disconnect the cat temperature control units (aka: cat ECUs) from the loom running to the Motronic. This will still throw a check engine light on the 5.2, but you'll at least be able to run the engine without the Motronic going into limp mode. 2) remove the muffler and have a look at the condition of the matrix inside the catalytic converters. If the ceramic is busted up it can clog the exhaust flow and cause the kind if drama your are having. You don't need any "bananas in your tail pipes". Now if the cats check out okay, try running it with the stinking cat tcu disconnected from the loom and see what happens.
I'm out of here. Too many bosses point to many fingers in different directions. All I'll say before leaving is that you have too many problems to not go about this in a orderly fashion. If you want to just around between cats, cam sensor, pre cat O2s, post cat O2s have at it. If you want to fix the car focus on one issue at a tome. Bye!
ketel, a lot of good help and information has been posted. I see you are in the San Francisco bay area. A wise investment in time and money may be to bring the 355 to a quality pro like Brian Crall. Brian has the SD diagnostic equipment required and a world of knowledge. Just a thought.
I have over 30 years fixing Ferraris and never used a pro mechanic since my first two years of tutoring under 3 FNA mechanics in the 80's. I have learned a lot since and I am a pretty advanced DIY'er. But that is not "just a thought" but a darn fine idea when one is out gunned on a project. We gain experience often through failure. There is nothing wrong with going to the pros. That should be considered. We will keep trying to help until ketel gives up.
Agree with this but just as a last check, look in the owners manual for the fuse I mentioned in post 176 and if it exists check it. Oxygen sensor heater fuse.
Quick update: Thermocouple TCUs came in yesterday and are now installed. There is still the matter of that lone thermocouple that was tied off to the side of the engine bay, but I will try to reinstall that shortly. Will advise ketel
Hi Ketel, sorry for being non-tech-related here, but in CA the vehicle seller is responsible for getting the car smogged less than 90 days before sale. Sorry if I missed any mention of this prior. If it was private party you're most likely SOL unless the guy/gal is truly a good person... However if you got the car at a dealer, even non-Ferrari, I would think they are at the very least partially on the hook for all this BS you're going through. Thoughts anyone?
On Sept 12th we all learned your TCU's were toast. The O2 sensors were also pronounced DOA. Until those are replaced nothing will change. Get the new O2 sensors installed along with the TCU's. Get that by-pass thermocouple installed properly (check the wiring as mine was reversed with the passnager side cat ECU). Set aside funds for three thermocouples. Clear the codes and give her a go. Everything from the 12th until today is speculation as you KNOW parts installed in the car are faulty. I had a list of codes similar to yours and it took awhile to troubleshoot but I got there.
Watson - Not sure if you kept up with the chronology here, but just to clear up any confusion, I already ordered and replaced all four 02 sensors a couple days ago. The TCUs did not arrive until yesterday, which is why they were not installed at the same time as the 02 sensors. So, as of today my 355 has all NEW TCUs (3) and 02 sensors (4). As such, they can now be eliminated from the list of variables. ketel
ketel, I know I said I was not going to post anymore but there is still the issue of the P0341 code, Cam position sensor (CPS). This is likely the source of your rough running and I would not expect it to go away (the rough running, rough idle) until it is resolved. The CPS controls the injection timing and if not working the ECU is basically guessing as to when to turn on the injectors. This leads to poor fuel economy, poor acceleration/throttle response and rough idle. Also, while I suggested getting your car to someone with an SD2 moons ago, since you have now replaced all sensors but the CPS, there is really no need to connect to an SD2 at this time. You will need to get out your VOM and start testing the wires for all these sensors for continuity and correctness, one by one. I.e., unplug the harness from the ECU and the sensors (one sensor at a time) and check for continuity between the sensor end of a wire and the corresponding pin on the ECU connector. Keep a record of which sensor and which sensor pin has continuity with which pin in the ECU connector. This will allow you to determine if you put any sensor wires back in the the wrong pin slot in the housings when you were doing the GCK install. And yes, check the O2 sensor fuse. It is inthe fuse box under the foor rest in the passangers side.
Sorry Ketel. I cant read this thread in full, some of the stuff in it just get me mad. OK, so you have all the parts in it now. Am I to understand that you still have the full list of codes despite the new ECU's, O2 sensors and reconnecting the bypass thermocouple?
and if there are any internally broken wires. You should also check for continuity between ground and each end of each wire to see if any are shorted to the chassis.
So, Last night I performed a drive cycle. I followed the Ferrari SOP to the letter. All in, I did about 20 miles. No CEL came on, but the SD light started flashing within minutes of pulling away and stayed flashing throughout the drive. Remember, I don't have a port for my exhaust bypass thermocouple given I have an aftermarket (Maranello brand) exhaust system. So, the probe is plugged into the TCU but tied off to the side. I was told that I would likely get a SDL and CEL from that but might be able to avoid it if I never revved the vehicle more than 4k rpm. Performance-wise, the vehicle was hesitant and shuttering. Idle was rough and there moments when the shuddering was so violent that I believed the vehicle would stall right there on the highway. Once the drive cycle was complete the vehicle *appeared* to run a bit better. Although I got no CEL, I plugged in the OBD2 and look for "pending codes". I had 7. They were: 1448 0341 0154 0134 1115 1119 1445 johnk has already remarked about the cam position sensor. I pulled the connector off and staring back were 3 perfectly placed gold terminals. Of course, it is impossible to see what's going on at the crimp itself without ravaging the boot and terminals and connector and having to re-do the GCK process on that connector. As to checking continuity, I have not done that before so this is yet another learning curve for me for lovely Ferrari ownership. Oh joy. Ideas and resources to check are welcome. ketel
Better. One code at a time... Did you plug the Bypass thermocouple in? Based on what I am looking at I think you did. My car did exactly what you described with SDL... I think you have the bypass thermocouple and passenger side thermocouple connections to the TCU's reversed. Swap them, clear codes and try again. That fixed mine. This will not fix all the codes but 1448, 1445 and the SDL should go away... One code at a time. Edit: Just read in detail about leaving the bypass thermocouple uninstalled. You will always get a 1448 code with that configuration. Still think the bypass / passenger Thermocouples are reversed.
Is there some reason why you are not going to check the O2 sensor heater fuse? Two of the codes are shouting out that its blown. Of course it might be perfectly fine but what is the reason for not checking the obvious first? Even if the fuse is OK, the codes are indicating some basic problem with the O2 sensor heater wiring. So find a wiring diagram and follow it through from the voltage source, a pin on the ECU, to the sensors and back to the ECU. This is a simple circuit which should be easy to troubleshoot assuming there is a wiring diagram available (is there?).
yep, some progress, several connection issues corrected, but still a couple of issues. Getting there.
