360 Modena - Codes w/o CEL

If any of you read the instructions in TSB 20 word-for-word, you will find some omissions within the steps. I now understand if you are unable to follow exactly the instructions, why not all of the readiness conditions will be complete. Thus it is not uncommon for several drive cycles (as suggested in post number 23) before all of the internal checks are eventually satisfied by the two engine ECUs. This may be accomplished by you driving around town; however, I suspect that during your normal driving habits some of the steps outlined in the TSB may not be met. Who intentionally slows from 4500 RPM in fourth gear to 2000 RPM without braking or clutching? Unless you do that, something the ECUs are supposed to check for won’t be, so your car may not be ready for inspection.

I have wondered what exactly the OBD2 is looking for at each of these steps. Despite me previously scoffing at that driving procedure as being impractical to achieve, with the gaps filled in (which Ferrari does not spell out for you, are you assumed to already know it, I didn’t) the purpose behind the driving procedure is more meaningful. Use the below in conjunction with the PDF that is in post number 8, to help understand the logic behind the steps which Ferrari outlines.

Step 1 - checks O2 sensor heating circuits, air pump, evaporative system

Step 2a - checks for ignition misfire, fuel trim, canister purge

Step 2b - checks EGR*, air pump, O2 sensors, canister purge

*My definition of EGR is exhaust gas recirculation, which I thought a 360 does not have. If so, then EGR could refer to any of several valves in the fuel vapor capture plumbing.

Step 2c - checks purge function during engine vacuum

Step 3 - ECU controls idle speed

Step 4a - checks misfire, fuel trim, purge

Step 4b - checks catalytic convert efficiency, misfire, EGR, fuel trim, O2 sensors, purge

Step 5 - checks EGR and purge

 

I was able to clear the secondary air readiness code on my car. I followed the FNA 20 driving reset procedure, paying particular attention to the step that outlines driving at 2500 RPM in fourth gear for 3.5 miles then gradually accelerating to 4500 RPM then slowing (without clutching or braking) to 2000 RPM.

My previous understanding was that each step of the driving procedure must be a seamless transition from one to the next. I now believe that to not be true, because as itemized in post # 26, in each step the ECU step is testing for specific parameters. After a parameter is okay, the ECU then tests the next parameter under different driving conditions. Each test is “independent” of each other, although all of the OBD systems are related one way or another, however slight.

Note in particular step 2C where the ECU is checking the purge functions. In these two schematics …

http://www.ricambiamerica.com/car-di...-air-pump.html

http://www.ricambiamerica.com/car-di...on-device.html

... you will see a number of valves which are part of the fuel vapor capture plumbing. Fundamentally, this is affected by engine vacuum, so the stronger the vacuum the more effective the purge.

After performing the prescribed ten minute drive at the end of that procedure I made a u-turn for the trip home. Being early in the morning there was no traffic, so I let the engine breath hard. I let off the gas at almost 160 MPH to let the engine slow the car down from about 7000 RPM to 3500 RM in sixth gear without clutching, so there was a stronger vacuum than in the step where I slowed from 4500 RPM to 2000 RPM in fourth gear.

I am not certain if clearing the secondary air readiness code was a result of slowing the car during normal driving or by slowing the car from the high-speed pass. It seems plausible the success of the purge function is dependent on how strong of a vacuum is being pulled on the evaporative system. Below are the conditions of the before and after readiness codes.
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FChatter mello turned me on to it. Harbor Freight has it for $70. It provides a host of other information which is recording while data logging. Other parameters that I find particularly useful are fuel trim, mass airflow and air intake temperature.

 

I previously used a wireless interface module that works with any number of free apps. One day my phone stopped communicating, no matter which of the three modules I plugged into the OBD port and no matter which of the three apps I have on my phone. I tried every combination then gave up and bought the Centech.

 

SECONDARY AIR SYSTEM -VALID FOR USA AND CDN MY 2000-2004- - Ricambi America, Inc.

ANTIEVAPORATION DEVICE -VALID FOR USA AND CDN MY 2000-2004- - Ricambi America, Inc.