97 F355 Spider ECU Issue/Smog Issue

I have a 1997 Ferrari F355 Spider that I just purchased that fails smog. It shows several codes indicating O2 sensors on bank 1, MAF sensor, and ECT sensor issues. I took the car into a Ferrari shop (not official Ferrari) to have it looked at. I have been told that since the chip was replaced with an aftermarket chip, their computer will not perform the diagnostics that they need to repair the issues. I have tried to contact the seller to see if I can obtain the original ECU chip, but he has been pretty unresponsive lately. I am far from an expert on this, so... 1) Does it make sense that the chip needs to be a factory chip to properly diagnose issues using a computer? 2) If so, is the chip something that could be purchased to help with the diagnostics, then sold (or even just borrowed)? Does anybody, who has upgraded their chips, have a spare original chip that I could buy, rent, or borrow?

 

I am not certain it is necessary. If you can pull the codes, then you are already halfway to the repair. Can you not go ahead and replace the faulty O2 sensors? You can buy Bosch generic 4 wire O2 sensor for $75 each if you don't mind solding the cable and plug from the oem one you remove. Same with the ECT sensor (electronic coolant temp) that is located to the right of the oil filter and is only $30. For the MAF you can order a new one online, just search using the Bosch part number on the MAF. It is also used on mid 1990's BMW 540's (E34 chassis I think). The Bosch # is 0280 217 800 and is $270 with free shipping from www.importecparts.com

 

I just hate to blow $1000 to find out that the wiring or something else is actually causing the faults. Anyway, is bank 1 on the driver's side or passenger side? Maybe I'll start by replacing the O2 sensors and seeing if it clears those codes.

 

Bank 1 is the passenger side. Also the code should say if it is the pre cat or post cat O2 sensor. 9 times out of 10 it is the pre-cat that fails. Only $500 for all these parts (and they would all be Bosch like oem) and you can swap them out yourself. Before you replace the MAF, it wouldn't hurt to remove it and flush it with some carb cleaner (or the product specific MAF cleaner by CRC) and also clean the connector on the side of it with some electrical contact cleaner. Once in a while that works...

 

I purchased an Equus 3100 OBD2 code reader and used it to reset all the codes over 200 miles ago. It is now showing code P1692. 1 = manufacturer specific, 6 = Computer Output Circuits 92=?????. It also shows P1115 ECT Sensor Intermittent High Voltage, P0137 O2 Circuit Low Voltage Bank 1 Sensor 2, P0102 Mass or Volume Air Flow Circuit Low Input, P1119 1 = manufacturer specific 1 = Fuel and Air Metering 19 = ?????, P0134 O2 Circuit No Activity Bank 1 Sensor 1.

 

Okay, let's go through these one at a time:

P1119 = O2 sensor heater circuit bank 2, sensor 1 (passenger side, pre cat sensor)

P1115 = O2 sensor heater circuit bank 1, sensor 1 (drivers side, pre cat sensor)

P0134 = O2 sensor, no activity bank 1, sensor 1 (drivers side, pre cat sensor again)
(so two problems are detected on the drivers side pre cat sensor, the heater inside it is not working, and the sensor is not sending an output either, on the passenger side, it is just the heater that is not working. Basically you need two new pre-cat O2 sensors!)

P0137 I cannot find, but appears to also be related to O2 sensor, could be for bank 1 sensor 2, based on it's position between P0136 and P0138 (post cat sensor listings)

P0102 is MAF as you stated

P1692 cannot find a listing

 

I would start with replacing both of your pre-cat O2 sensors (that seems to be most of your troubles), one on each side, and cleaning the MAF. Reset the codes and drive it for a while.

You might call your local FNA dealer or independant for help on the P0137 and P1692 codes and report back on what they are.
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Here are the P codes for the 360, most of them cross over to the 355, but not all. (I can confirm the P1115 and P1119 codes cross over, as I have had them, and replacing the pre-cat O2 sensors corrected the problem.
View attachment DTCs[1].pdf

 

P0137 - Sensor Circuit Low Voltage (Bank 1 Sensor 2)
P1692, Not Listed!

 

All I can find on P1692
P1692 Porsche MIL (Check Engine Light) Short To Ground
P1692 Saab Check Engine Light Short To Ground
P1692 Toyota OCV Open Malfunction
P1692 Volkswagen MIL Short To Ground

Hope this is some help!
I know how frustrating this can be !!!!!

 

P0137 O2 Circuit Low Voltage Bank 1 Sensor 2
The reader says P0137 is a standard code for Bank 1 Sensor 2. So I have 3 bad O2 sensors? Both pre-cats and one post cat?

 

Yes, it certainly appears so.

 

OK. So I replaced the driver's side O2 sensor with no apparent issues. I haven't tried it yet though. I started working on the passenger side O2 sensor and started wondering if the previous owner may have connected the pre cat sensor to the post cat sensor plug and vice versa. I verified that there is no keying on the plugs to prevent this from happening. I also noticed that there is blue tape around one of the wire sets on each side. The driver's side post cat sensor has blue tape, however, the passenger side pre cat sensor has blue tape. This looks like a problem. How do I confirm which plug is for pre cat and which is for post cat?

 

I think I figured out which was which on the plug. I have replaced both O2 sensors, cleaned the MAF and its contacts, and cleared the codes. Now I am showing:
P1691 ????
P0131 O2 Circuit Low Voltage (Bank 1, Sensor 1)
P0151 O2 Circuit Low Voltage (Bank 2, Sensor 1)
P0137 O2 Circuit Low Voltage (Bank 1, Sensor 2)
P0157 O2 Circuit Low Voltage (Bank 2, Sensor 2)
P0102 Mass or Volume Air Flow Circuit Low Input

 

Do you have a "check engine" light showing with these codes?

 

No, but I'm not sure if it is connected. The previous owner had the Tubi test pipes on. The CEL lights up when I start the car, then turns off, which I think is normal.

 

That is normal, CE light on at start up, then goes out, that is the "self test" function. I would ignore those codes for now, and drive the car. Do not clear what is in there, and see if after a few drives it trips the CE light or not. I just find it weird you are getting the generic codes but not the manufacturer specific codes any longer. As long as you are not getting the Ferrari codes, I would at least drive it and see what happens.

 

Can I disconnect one of the sensor plugs and measure the voltage? If so, which would I measure? The heater? Would I expect 12V? Or do you think these are false codes that will clear after a few drives?

 

Gray is ground, black is signal.

http://www.buzzle.com/articles/oxygen-sensor-testing.html

(btw, I have never done this, but I do use Google )

I have never had to do this, because when I replaced the bad O2 sensors on my 355 (two different instances, right side pre-cat, then a year later, left side pre-cat), the codes never came back.

I think the chance of the O2 sensors not working is very slim. BUT, it is possible there is a wiring problem with the plugs from the sensor plugs back to the motronic...but again, all four seems mightly slim too. That is why I think you should just drive it for a while.

 

Sensors with blue tape or blue dot are the PRE-cat.

For what concerns the DTC investigation and the monitoring of O2 sensors signal, you have an OBD2 car, take benefit of it. You can plug an OBD2 reader, a laptop or a PDA an have real time reading of the data (see picture). Oscilloscope investigation will be a second step : 12V between the white wires car-side (heater), voltage swinging between around 0.1V and 0.9V on the grey and black wires sensor-side. Be carefull not to allow the sensor to cool down for this measurement.
Image Unavailable, Please Login

 

I have an Equus 3100a OBD2 reader. I think it only reads codes. I can't find how to read O2 sensor information.
For the .1V to .9V swing, do I just need to look at the output of the sensor without it plugged into the receiving connector? Is it a DC level that I can measure with my handheld meter, or do I need a scope?

 

Sorry, I don't know your OBD2 reader, but for some $ you can find on ebay some very cheap interface and free softwares which will allow you to connect a laptop to your car and have access to live data when the engine is running (eg: access to the 4 O2 sensors, rpm, speed, water temp, air temp, fuel trimming, tps, ...). Very very useful IMO.

Yes you can look at the output of the sensors while they are disconnected from the car BUT they must be warm. In that case the ECU will work in open loop and you will see a voltage rather stable somewhere in the range 0.1V to 0.9V. To perform a good check, you must look at them with an oscilloscope while they are still connected in order to see the voltage swing between 0.1V and 0.9V due to ECU correction.

 

I disconnected one of the pre-cat sensors and verified 12V across the heater terminals on the car end and a voltage varying between .5V and .8V across the sensor output on the sensor end with the car running and after a 15 minute drive. So I think the sensors are working. Any idea where the other end of the cable is? Does it go straight into the computer behind the passenger seat? If so, does anyone know which pin I should look at on the connector? If not, does anyone know where I find the other end of the cable. Sorry, I am a bit of a newbie at this.

 

To save me the research time, could you recommend a brand? Or a couple brands that I could look at?

 

The sensors wires are going staight to the Motronic. the pin function is the following:
- front right sensor between pins 19 and 46
- rear right sensor between pins 77 and 46
- front left sensor between pins 18 and 46
- rear left sensor between pins 76 and 46
No need to go to the Motronic connector to check the wires. Disconnect the O2 sensor connectors and measure the voltages between the 5 pins above and the ground, on the car side. You should see a stable voltage around 1V

0.5V - 0.8V are not normal values when the engine is idling. It should swing between 0.1 or 0.2V and 0.8V. Did you measure with an oscilloscope?
The problem can be the sensor itself or the fact that the car is not running in closed loop ie no rich/lean mixture alternance based on O2 sensor. Your car seems continuously on the rich side. Does your reader allow you to see live data? The open loop/closed loop status is one of the data we can get from the Motronic.

 

Sorry, no particuliar brand I can recommend. To save you some time, try the following search on ebay : "ELM323" or "ELM327". You should find a lot of cheap interfaces which will allow you to connect a laptop to your car.