355 CEL assistance needed

You could easily eliminate the grounding question by carefully clamping a wire on the outside of each 02 sensor body and grounding it out. Clear the codes and drive it for a while and see what happens.

 

As a reference to this site it was my car that was repaired in Atlanta. I also had a CEL that indicated the O2 sensors were putting out "low voltage". I replaced them all with generic Bosch units (Daniel, it was late and I needed to get this done). The very same codes came back after about ten minutes of driving.

My car was running great and had completed the major service about two years prior. I drove it to Atlanta after speaking with Tom at Sport Auto to have them evaluate and repair it. After they checked the wire harness they said they wanted to replace all of the O2 sensors with Ferrari spec units. They have completed this and now report that the light is off and the car has no codes. I'm headed down there as soon as time permits to do some driving.

I know that you have already replaced your O2 sensors without change in the CEL. I've seen cars "run" with the valves incorrectly timed and after hearing your car I think that the chance of this being the problem is zero.

The charge for their diagnostic work and replacement of the sensors was less than 2K, well worth it.

ken

 

There are quite a few codes that reference 02 sensors. Remember O2 sensors are monitors, all they can do is react to input. When a code comes up with O2 sensor it is usually a reaction to what is happening TO them, not BY them.

 

Downstream O2's are often affected by upstream problems. Also the downstream O2's monitoring by the Motronic can be very fussy. I have seen several cases of non OE cats causing that same fault. I have not experienced it with Hyperflows but see no reason they should be any different. The parameters are very narrow and are not consistant from car to car. When they were new we were often given ECU's to install that would not set an error code if you started putting bullets through the motor.
The best plan is to disconnect them and do some diagnosis of basic running. With O2's disconnected the car should run perfectly. If it does not the O2's are trying to make it run correctly and that is not their job. The bad part is that the sensor is responding to exhaust gas and the best way to know why is a good 4 or 5 gas tester which most DIYers dont have. You also need a good understanding of what various gas concentrations mean. In this particular case and others like it the Ferrari diagnosis units are often more of a crutch than anything else and used to sell parts when what is needed is old fashioned basic diagnosis.

 

Bosch idle speed regulator...I had mine come loose too...like majorly and I could hear this huge sucking sound...only a few blocks from home, so immediately drove home and resecured it...no biggie. But it had probably been loose for several weeks, and never threw a CE light. Just my experience an FYI. Who know's, it may be what threw your CE light.

 

Can someone post of picture of this item and point out what came
loose?

 

A few questions for Rifledriver...or anyone that knows..
At my previous job we had a Baum scantool for the german cars we worked on and it was a requirement to reset a parameter listed as "adaptation" whenever any service was done. I reasoned the ECM adapted to the old running condition and therefore had to be cleared out with the scanner to avoid bogus codes and/or running problems. The questions are, does Ferrari (355 and newer) have a similar set up? or is the 'Idle for ten minutes' enough to re-learn? Also, will resetting the I/M readiness tests (done when codes are cleared with generic OBD-2 scanner) have the same effect? I miss knowing for sure that I am starting with a clean slate after a repair.

Thanks

Erik

 

Ours would be different that what you have on a 1995. We have one, you have two. It is an air intake bypass from just past the mass air flow meter.

 

Are we talkin about this device? I have a 95 and there is one on each side. They are located just bellow the airflow meters.
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There ya go. You should see a electrical plug to it too.

 

Did you already try adding a ground to them? If so, then you might go back and disconnect them all, clean the connections with some CRC electrical contact cleaner (or equivalent) then treat with Stabilant 22. Just a stab in the dark (and unlikely to help) but may be worth a try if you have some time on your hands.

It is also entirely possible that one of your "new" O2 sensors is defective.

 

I've been asked for an update on my car: I haven't driven it yet as it is getting a major service at Ferrari of Atlanta.

ken

 

Ok, I had an issue with the same thing. You said that you replaced the O2 sensors correct? I decided that for a weekend I would replace the plugs and O2 sensors for a quick tune-up on my car. I ordered my O2 sensors from what I thought was a reputable place. I went to there website and ordered them following their menu. I was getting the same CEL as you. To make a long story short. I eventually called Ferrari to see if the O2 sensors were the right ones. They were not. So make sure that the O2 sensors you have are the correct replacement parts first! Of course once I replaced them with the correct parts everything was fine.

Happy Motoring
Steven

 

Since your car is a 99 might want to check into the warranty. If there is an issue with lets say the ECU you should be able to get it replaced at no charge. I believe that the warranty which covers smog related components is good for 8 years or 80k miles. Definately worth the time of a phone call to Ferrari if is true.

Steven

 

This is a relatively new law that is overseen by the EPA which protects the consumer. It is the Design and Defect warranty. It covers the emission components of your car. Try this. http://www.epa.gov/obd/warranties.htm (cut n paste into your browser) Now go in there and talk with some authority and get it done!

Fingers crossed,
Steven

 

Steve,
I have read that document before, unfortunately, under the 8year/80,000 mile emission warranty, only the following are covered:

Catalytic converters.
The electronic emissions control unit or computer (ECU).
The onboard emissions diagnostic device or computer (OBD).


I very limited list of items.